Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * verify_nbtree.c
4 : : * Verifies the integrity of nbtree indexes based on invariants.
5 : : *
6 : : * For B-Tree indexes, verification includes checking that each page in the
7 : : * target index has items in logical order as reported by an insertion scankey
8 : : * (the insertion scankey sort-wise NULL semantics are needed for
9 : : * verification).
10 : : *
11 : : * When index-to-heap verification is requested, a Bloom filter is used to
12 : : * fingerprint all tuples in the target index, as the index is traversed to
13 : : * verify its structure. A heap scan later uses Bloom filter probes to verify
14 : : * that every visible heap tuple has a matching index tuple.
15 : : *
16 : : *
17 : : * Copyright (c) 2017-2024, PostgreSQL Global Development Group
18 : : *
19 : : * IDENTIFICATION
20 : : * contrib/amcheck/verify_nbtree.c
21 : : *
22 : : *-------------------------------------------------------------------------
23 : : */
24 : : #include "postgres.h"
25 : :
26 : : #include "access/heaptoast.h"
27 : : #include "access/htup_details.h"
28 : : #include "access/nbtree.h"
29 : : #include "access/table.h"
30 : : #include "access/tableam.h"
31 : : #include "access/transam.h"
32 : : #include "access/xact.h"
33 : : #include "catalog/index.h"
34 : : #include "catalog/pg_am.h"
35 : : #include "catalog/pg_opfamily_d.h"
36 : : #include "commands/tablecmds.h"
37 : : #include "common/pg_prng.h"
38 : : #include "lib/bloomfilter.h"
39 : : #include "miscadmin.h"
40 : : #include "storage/lmgr.h"
41 : : #include "storage/smgr.h"
42 : : #include "utils/guc.h"
43 : : #include "utils/memutils.h"
44 : : #include "utils/snapmgr.h"
45 : :
46 : :
2593 andres@anarazel.de 47 :CBC 317 : PG_MODULE_MAGIC;
48 : :
49 : : /*
50 : : * A B-Tree cannot possibly have this many levels, since there must be one
51 : : * block per level, which is bound by the range of BlockNumber:
52 : : */
53 : : #define InvalidBtreeLevel ((uint32) InvalidBlockNumber)
54 : : #define BTreeTupleGetNKeyAtts(itup, rel) \
55 : : Min(IndexRelationGetNumberOfKeyAttributes(rel), BTreeTupleGetNAtts(itup, rel))
56 : :
57 : : /*
58 : : * State associated with verifying a B-Tree index
59 : : *
60 : : * target is the point of reference for a verification operation.
61 : : *
62 : : * Other B-Tree pages may be allocated, but those are always auxiliary (e.g.,
63 : : * they are current target's child pages). Conceptually, problems are only
64 : : * ever found in the current target page (or for a particular heap tuple during
65 : : * heapallindexed verification). Each page found by verification's left/right,
66 : : * top/bottom scan becomes the target exactly once.
67 : : */
68 : : typedef struct BtreeCheckState
69 : : {
70 : : /*
71 : : * Unchanging state, established at start of verification:
72 : : */
73 : :
74 : : /* B-Tree Index Relation and associated heap relation */
75 : : Relation rel;
76 : : Relation heaprel;
77 : : /* rel is heapkeyspace index? */
78 : : bool heapkeyspace;
79 : : /* ShareLock held on heap/index, rather than AccessShareLock? */
80 : : bool readonly;
81 : : /* Also verifying heap has no unindexed tuples? */
82 : : bool heapallindexed;
83 : : /* Also making sure non-pivot tuples can be found by new search? */
84 : : bool rootdescend;
85 : : /* Also check uniqueness constraint if index is unique */
86 : : bool checkunique;
87 : : /* Per-page context */
88 : : MemoryContext targetcontext;
89 : : /* Buffer access strategy */
90 : : BufferAccessStrategy checkstrategy;
91 : :
92 : : /*
93 : : * Info for uniqueness checking. Fill these fields once per index check.
94 : : */
95 : : IndexInfo *indexinfo;
96 : : Snapshot snapshot;
97 : :
98 : : /*
99 : : * Mutable state, for verification of particular page:
100 : : */
101 : :
102 : : /* Current target page */
103 : : Page target;
104 : : /* Target block number */
105 : : BlockNumber targetblock;
106 : : /* Target page's LSN */
107 : : XLogRecPtr targetlsn;
108 : :
109 : : /*
110 : : * Low key: high key of left sibling of target page. Used only for child
111 : : * verification. So, 'lowkey' is kept only when 'readonly' is set.
112 : : */
113 : : IndexTuple lowkey;
114 : :
115 : : /*
116 : : * The rightlink and incomplete split flag of block one level down to the
117 : : * target page, which was visited last time via downlink from target page.
118 : : * We use it to check for missing downlinks.
119 : : */
120 : : BlockNumber prevrightlink;
121 : : bool previncompletesplit;
122 : :
123 : : /*
124 : : * Mutable state, for optional heapallindexed verification:
125 : : */
126 : :
127 : : /* Bloom filter fingerprints B-Tree index */
128 : : bloom_filter *filter;
129 : : /* Debug counter */
130 : : int64 heaptuplespresent;
131 : : } BtreeCheckState;
132 : :
133 : : /*
134 : : * Starting point for verifying an entire B-Tree index level
135 : : */
136 : : typedef struct BtreeLevel
137 : : {
138 : : /* Level number (0 is leaf page level). */
139 : : uint32 level;
140 : :
141 : : /* Left most block on level. Scan of level begins here. */
142 : : BlockNumber leftmost;
143 : :
144 : : /* Is this level reported as "true" root level by meta page? */
145 : : bool istruerootlevel;
146 : : } BtreeLevel;
147 : :
148 : 88 : PG_FUNCTION_INFO_V1(bt_index_check);
149 : 60 : PG_FUNCTION_INFO_V1(bt_index_parent_check);
150 : :
151 : : static void bt_index_check_internal(Oid indrelid, bool parentcheck,
152 : : bool heapallindexed, bool rootdescend,
153 : : bool checkunique);
154 : : static inline void btree_index_checkable(Relation rel);
155 : : static inline bool btree_index_mainfork_expected(Relation rel);
156 : : static void bt_check_every_level(Relation rel, Relation heaprel,
157 : : bool heapkeyspace, bool readonly, bool heapallindexed,
158 : : bool rootdescend, bool checkunique);
159 : : static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state,
160 : : BtreeLevel level);
161 : : static bool bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
162 : : BlockNumber start,
163 : : BTPageOpaque start_opaque);
164 : : static void bt_recheck_sibling_links(BtreeCheckState *state,
165 : : BlockNumber btpo_prev_from_target,
166 : : BlockNumber leftcurrent);
167 : : static bool heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid);
168 : : static void bt_report_duplicate(BtreeCheckState *state, ItemPointer tid,
169 : : BlockNumber block, OffsetNumber offset,
170 : : int posting, ItemPointer nexttid,
171 : : BlockNumber nblock, OffsetNumber noffset,
172 : : int nposting);
173 : : static void bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
174 : : BlockNumber targetblock,
175 : : OffsetNumber offset, int *lVis_i,
176 : : ItemPointer *lVis_tid,
177 : : OffsetNumber *lVis_offset,
178 : : BlockNumber *lVis_block);
179 : : static void bt_target_page_check(BtreeCheckState *state);
180 : : static BTScanInsert bt_right_page_check_scankey(BtreeCheckState *state,
181 : : OffsetNumber *rightfirstoffset);
182 : : static void bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
183 : : OffsetNumber downlinkoffnum);
184 : : static void bt_child_highkey_check(BtreeCheckState *state,
185 : : OffsetNumber target_downlinkoffnum,
186 : : Page loaded_child,
187 : : uint32 target_level);
188 : : static void bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
189 : : BlockNumber blkno, Page page);
190 : : static void bt_tuple_present_callback(Relation index, ItemPointer tid,
191 : : Datum *values, bool *isnull,
192 : : bool tupleIsAlive, void *checkstate);
193 : : static IndexTuple bt_normalize_tuple(BtreeCheckState *state,
194 : : IndexTuple itup);
195 : : static inline IndexTuple bt_posting_plain_tuple(IndexTuple itup, int n);
196 : : static bool bt_rootdescend(BtreeCheckState *state, IndexTuple itup);
197 : : static inline bool offset_is_negative_infinity(BTPageOpaque opaque,
198 : : OffsetNumber offset);
199 : : static inline bool invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
200 : : OffsetNumber upperbound);
201 : : static inline bool invariant_leq_offset(BtreeCheckState *state,
202 : : BTScanInsert key,
203 : : OffsetNumber upperbound);
204 : : static inline bool invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
205 : : OffsetNumber lowerbound);
206 : : static inline bool invariant_l_nontarget_offset(BtreeCheckState *state,
207 : : BTScanInsert key,
208 : : BlockNumber nontargetblock,
209 : : Page nontarget,
210 : : OffsetNumber upperbound);
211 : : static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum);
212 : : static inline BTScanInsert bt_mkscankey_pivotsearch(Relation rel,
213 : : IndexTuple itup);
214 : : static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block,
215 : : Page page, OffsetNumber offset);
216 : : static inline ItemPointer BTreeTupleGetHeapTIDCareful(BtreeCheckState *state,
217 : : IndexTuple itup, bool nonpivot);
218 : : static inline ItemPointer BTreeTupleGetPointsToTID(IndexTuple itup);
219 : :
220 : : /*
221 : : * bt_index_check(index regclass, heapallindexed boolean, checkunique boolean)
222 : : *
223 : : * Verify integrity of B-Tree index.
224 : : *
225 : : * Acquires AccessShareLock on heap & index relations. Does not consider
226 : : * invariants that exist between parent/child pages. Optionally verifies
227 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
228 : : */
229 : : Datum
230 : 3968 : bt_index_check(PG_FUNCTION_ARGS)
231 : : {
232 : 3968 : Oid indrelid = PG_GETARG_OID(0);
2206 233 : 3968 : bool heapallindexed = false;
169 akorotkov@postgresql 234 :GNC 3968 : bool checkunique = false;
235 : :
236 [ + + ]: 3968 : if (PG_NARGS() >= 2)
2206 andres@anarazel.de 237 :CBC 3962 : heapallindexed = PG_GETARG_BOOL(1);
169 akorotkov@postgresql 238 [ + + ]:GNC 3968 : if (PG_NARGS() == 3)
239 : 686 : checkunique = PG_GETARG_BOOL(2);
240 : :
241 : 3968 : bt_index_check_internal(indrelid, false, heapallindexed, false, checkunique);
242 : :
2593 andres@anarazel.de 243 :CBC 3942 : PG_RETURN_VOID();
244 : : }
245 : :
246 : : /*
247 : : * bt_index_parent_check(index regclass, heapallindexed boolean, rootdescend boolean, checkunique boolean)
248 : : *
249 : : * Verify integrity of B-Tree index.
250 : : *
251 : : * Acquires ShareLock on heap & index relations. Verifies that downlinks in
252 : : * parent pages are valid lower bounds on child pages. Optionally verifies
253 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
254 : : */
255 : : Datum
256 : 60 : bt_index_parent_check(PG_FUNCTION_ARGS)
257 : : {
258 : 60 : Oid indrelid = PG_GETARG_OID(0);
2206 259 : 60 : bool heapallindexed = false;
1852 pg@bowt.ie 260 : 60 : bool rootdescend = false;
169 akorotkov@postgresql 261 :GNC 60 : bool checkunique = false;
262 : :
1852 pg@bowt.ie 263 [ + + ]:CBC 60 : if (PG_NARGS() >= 2)
2206 andres@anarazel.de 264 : 55 : heapallindexed = PG_GETARG_BOOL(1);
169 akorotkov@postgresql 265 [ + + ]:GNC 60 : if (PG_NARGS() >= 3)
1852 pg@bowt.ie 266 :CBC 52 : rootdescend = PG_GETARG_BOOL(2);
169 akorotkov@postgresql 267 [ + + ]:GNC 60 : if (PG_NARGS() == 4)
268 : 26 : checkunique = PG_GETARG_BOOL(3);
269 : :
270 : 60 : bt_index_check_internal(indrelid, true, heapallindexed, rootdescend, checkunique);
271 : :
2593 andres@anarazel.de 272 :CBC 43 : PG_RETURN_VOID();
273 : : }
274 : :
275 : : /*
276 : : * Helper for bt_index_[parent_]check, coordinating the bulk of the work.
277 : : */
278 : : static void
1852 pg@bowt.ie 279 : 4028 : bt_index_check_internal(Oid indrelid, bool parentcheck, bool heapallindexed,
280 : : bool rootdescend, bool checkunique)
281 : : {
282 : : Oid heapid;
283 : : Relation indrel;
284 : : Relation heaprel;
285 : : LOCKMODE lockmode;
286 : : Oid save_userid;
287 : : int save_sec_context;
288 : : int save_nestlevel;
289 : :
2593 andres@anarazel.de 290 [ + + ]: 4028 : if (parentcheck)
291 : 60 : lockmode = ShareLock;
292 : : else
293 : 3968 : lockmode = AccessShareLock;
294 : :
295 : : /*
296 : : * We must lock table before index to avoid deadlocks. However, if the
297 : : * passed indrelid isn't an index then IndexGetRelation() will fail.
298 : : * Rather than emitting a not-very-helpful error message, postpone
299 : : * complaining, expecting that the is-it-an-index test below will fail.
300 : : *
301 : : * In hot standby mode this will raise an error when parentcheck is true.
302 : : */
303 : 4028 : heapid = IndexGetRelation(indrelid, true);
304 [ + + ]: 4028 : if (OidIsValid(heapid))
305 : : {
1910 306 : 4024 : heaprel = table_open(heapid, lockmode);
307 : :
308 : : /*
309 : : * Switch to the table owner's userid, so that any index functions are
310 : : * run as that user. Also lock down security-restricted operations
311 : : * and arrange to make GUC variable changes local to this command.
312 : : */
706 noah@leadboat.com 313 : 4024 : GetUserIdAndSecContext(&save_userid, &save_sec_context);
314 : 4024 : SetUserIdAndSecContext(heaprel->rd_rel->relowner,
315 : : save_sec_context | SECURITY_RESTRICTED_OPERATION);
316 : 4024 : save_nestlevel = NewGUCNestLevel();
41 jdavis@postgresql.or 317 :GNC 4024 : RestrictSearchPath();
318 : : }
319 : : else
320 : : {
2593 andres@anarazel.de 321 :CBC 4 : heaprel = NULL;
322 : : /* Set these just to suppress "uninitialized variable" warnings */
706 noah@leadboat.com 323 : 4 : save_userid = InvalidOid;
324 : 4 : save_sec_context = -1;
325 : 4 : save_nestlevel = -1;
326 : : }
327 : :
328 : : /*
329 : : * Open the target index relations separately (like relation_openrv(), but
330 : : * with heap relation locked first to prevent deadlocking). In hot
331 : : * standby mode this will raise an error when parentcheck is true.
332 : : *
333 : : * There is no need for the usual indcheckxmin usability horizon test
334 : : * here, even in the heapallindexed case, because index undergoing
335 : : * verification only needs to have entries for a new transaction snapshot.
336 : : * (If this is a parentcheck verification, there is no question about
337 : : * committed or recently dead heap tuples lacking index entries due to
338 : : * concurrent activity.)
339 : : */
2593 andres@anarazel.de 340 : 4028 : indrel = index_open(indrelid, lockmode);
341 : :
342 : : /*
343 : : * Since we did the IndexGetRelation call above without any lock, it's
344 : : * barely possible that a race against an index drop/recreation could have
345 : : * netted us the wrong table.
346 : : */
347 [ + - - + ]: 4024 : if (heaprel == NULL || heapid != IndexGetRelation(indrelid, false))
2593 andres@anarazel.de 348 [ # # ]:UBC 0 : ereport(ERROR,
349 : : (errcode(ERRCODE_UNDEFINED_TABLE),
350 : : errmsg("could not open parent table of index \"%s\"",
351 : : RelationGetRelationName(indrel))));
352 : :
353 : : /* Relation suitable for checking as B-Tree? */
2593 andres@anarazel.de 354 :CBC 4024 : btree_index_checkable(indrel);
355 : :
1707 pg@bowt.ie 356 [ + - ]: 4023 : if (btree_index_mainfork_expected(indrel))
357 : : {
358 : : bool heapkeyspace,
359 : : allequalimage;
360 : :
1007 tgl@sss.pgh.pa.us 361 [ + + ]: 4023 : if (!smgrexists(RelationGetSmgr(indrel), MAIN_FORKNUM))
1707 pg@bowt.ie 362 [ + - ]: 18 : ereport(ERROR,
363 : : (errcode(ERRCODE_INDEX_CORRUPTED),
364 : : errmsg("index \"%s\" lacks a main relation fork",
365 : : RelationGetRelationName(indrel))));
366 : :
367 : : /* Extract metadata from metapage, and sanitize it in passing */
309 368 : 4005 : _bt_metaversion(indrel, &heapkeyspace, &allequalimage);
1347 369 [ + + - + ]: 4005 : if (allequalimage && !heapkeyspace)
1347 pg@bowt.ie 370 [ # # ]:UBC 0 : ereport(ERROR,
371 : : (errcode(ERRCODE_INDEX_CORRUPTED),
372 : : errmsg("index \"%s\" metapage has equalimage field set on unsupported nbtree version",
373 : : RelationGetRelationName(indrel))));
1347 pg@bowt.ie 374 [ + + - + ]:CBC 4005 : if (allequalimage && !_bt_allequalimage(indrel, false))
375 : : {
183 noah@leadboat.com 376 :UBC 0 : bool has_interval_ops = false;
377 : :
378 [ # # ]: 0 : for (int i = 0; i < IndexRelationGetNumberOfKeyAttributes(indrel); i++)
379 [ # # ]: 0 : if (indrel->rd_opfamily[i] == INTERVAL_BTREE_FAM_OID)
380 : 0 : has_interval_ops = true;
1347 pg@bowt.ie 381 [ # # # # ]: 0 : ereport(ERROR,
382 : : (errcode(ERRCODE_INDEX_CORRUPTED),
383 : : errmsg("index \"%s\" metapage incorrectly indicates that deduplication is safe",
384 : : RelationGetRelationName(indrel)),
385 : : has_interval_ops
386 : : ? errhint("This is known of \"interval\" indexes last built on a version predating 2023-11.")
387 : : : 0));
388 : : }
389 : :
390 : : /* Check index, possibly against table it is an index on */
1707 pg@bowt.ie 391 :CBC 4005 : bt_check_every_level(indrel, heaprel, heapkeyspace, parentcheck,
392 : : heapallindexed, rootdescend, checkunique);
393 : : }
394 : :
395 : : /* Roll back any GUC changes executed by index functions */
706 noah@leadboat.com 396 : 3985 : AtEOXact_GUC(false, save_nestlevel);
397 : :
398 : : /* Restore userid and security context */
399 : 3985 : SetUserIdAndSecContext(save_userid, save_sec_context);
400 : :
401 : : /*
402 : : * Release locks early. That's ok here because nothing in the called
403 : : * routines will trigger shared cache invalidations to be sent, so we can
404 : : * relax the usual pattern of only releasing locks after commit.
405 : : */
2593 andres@anarazel.de 406 : 3985 : index_close(indrel, lockmode);
407 [ + - ]: 3985 : if (heaprel)
1910 408 : 3985 : table_close(heaprel, lockmode);
2593 409 : 3985 : }
410 : :
411 : : /*
412 : : * Basic checks about the suitability of a relation for checking as a B-Tree
413 : : * index.
414 : : *
415 : : * NB: Intentionally not checking permissions, the function is normally not
416 : : * callable by non-superusers. If granted, it's useful to be able to check a
417 : : * whole cluster.
418 : : */
419 : : static inline void
420 : 4024 : btree_index_checkable(Relation rel)
421 : : {
422 [ + - ]: 4024 : if (rel->rd_rel->relkind != RELKIND_INDEX ||
423 [ + + ]: 4024 : rel->rd_rel->relam != BTREE_AM_OID)
424 [ + - ]: 1 : ereport(ERROR,
425 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
426 : : errmsg("only B-Tree indexes are supported as targets for verification"),
427 : : errdetail("Relation \"%s\" is not a B-Tree index.",
428 : : RelationGetRelationName(rel))));
429 : :
430 [ - + - - ]: 4023 : if (RELATION_IS_OTHER_TEMP(rel))
2593 andres@anarazel.de 431 [ # # ]:UBC 0 : ereport(ERROR,
432 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
433 : : errmsg("cannot access temporary tables of other sessions"),
434 : : errdetail("Index \"%s\" is associated with temporary relation.",
435 : : RelationGetRelationName(rel))));
436 : :
1935 peter_e@gmx.net 437 [ - + ]:CBC 4023 : if (!rel->rd_index->indisvalid)
2593 andres@anarazel.de 438 [ # # ]:UBC 0 : ereport(ERROR,
439 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
440 : : errmsg("cannot check index \"%s\"",
441 : : RelationGetRelationName(rel)),
442 : : errdetail("Index is not valid.")));
2593 andres@anarazel.de 443 :CBC 4023 : }
444 : :
445 : : /*
446 : : * Check if B-Tree index relation should have a file for its main relation
447 : : * fork. Verification uses this to skip unlogged indexes when in hot standby
448 : : * mode, where there is simply nothing to verify. We behave as if the
449 : : * relation is empty.
450 : : *
451 : : * NB: Caller should call btree_index_checkable() before calling here.
452 : : */
453 : : static inline bool
1707 pg@bowt.ie 454 : 4023 : btree_index_mainfork_expected(Relation rel)
455 : : {
456 [ - + ]: 4023 : if (rel->rd_rel->relpersistence != RELPERSISTENCE_UNLOGGED ||
1707 pg@bowt.ie 457 [ # # ]:UBC 0 : !RecoveryInProgress())
1707 pg@bowt.ie 458 :CBC 4023 : return true;
459 : :
916 pg@bowt.ie 460 [ # # ]:UBC 0 : ereport(DEBUG1,
461 : : (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
462 : : errmsg("cannot verify unlogged index \"%s\" during recovery, skipping",
463 : : RelationGetRelationName(rel))));
464 : :
1707 465 : 0 : return false;
466 : : }
467 : :
468 : : /*
469 : : * Main entry point for B-Tree SQL-callable functions. Walks the B-Tree in
470 : : * logical order, verifying invariants as it goes. Optionally, verification
471 : : * checks if the heap relation contains any tuples that are not represented in
472 : : * the index but should be.
473 : : *
474 : : * It is the caller's responsibility to acquire appropriate heavyweight lock on
475 : : * the index relation, and advise us if extra checks are safe when a ShareLock
476 : : * is held. (A lock of the same type must also have been acquired on the heap
477 : : * relation.)
478 : : *
479 : : * A ShareLock is generally assumed to prevent any kind of physical
480 : : * modification to the index structure, including modifications that VACUUM may
481 : : * make. This does not include setting of the LP_DEAD bit by concurrent index
482 : : * scans, although that is just metadata that is not able to directly affect
483 : : * any check performed here. Any concurrent process that might act on the
484 : : * LP_DEAD bit being set (recycle space) requires a heavyweight lock that
485 : : * cannot be held while we hold a ShareLock. (Besides, even if that could
486 : : * happen, the ad-hoc recycling when a page might otherwise split is performed
487 : : * per-page, and requires an exclusive buffer lock, which wouldn't cause us
488 : : * trouble. _bt_delitems_vacuum() may only delete leaf items, and so the extra
489 : : * parent/child check cannot be affected.)
490 : : */
491 : : static void
1852 pg@bowt.ie 492 :CBC 4005 : bt_check_every_level(Relation rel, Relation heaprel, bool heapkeyspace,
493 : : bool readonly, bool heapallindexed, bool rootdescend,
494 : : bool checkunique)
495 : : {
496 : : BtreeCheckState *state;
497 : : Page metapage;
498 : : BTMetaPageData *metad;
499 : : uint32 previouslevel;
500 : : BtreeLevel current;
2206 andres@anarazel.de 501 : 4005 : Snapshot snapshot = SnapshotAny;
502 : :
1465 pg@bowt.ie 503 [ + + ]: 4005 : if (!readonly)
504 [ + + ]: 3956 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\"",
505 : : RelationGetRelationName(rel));
506 : : else
507 [ + + ]: 49 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\" with cross-level checks",
508 : : RelationGetRelationName(rel));
509 : :
510 : : /*
511 : : * This assertion matches the one in index_getnext_tid(). See page
512 : : * recycling/"visible to everyone" notes in nbtree README.
513 : : */
1341 andres@anarazel.de 514 [ - + ]: 4005 : Assert(TransactionIdIsValid(RecentXmin));
515 : :
516 : : /*
517 : : * Initialize state for entire verification operation
518 : : */
2181 teodor@sigaev.ru 519 : 4005 : state = palloc0(sizeof(BtreeCheckState));
2593 andres@anarazel.de 520 : 4005 : state->rel = rel;
2206 521 : 4005 : state->heaprel = heaprel;
1852 pg@bowt.ie 522 : 4005 : state->heapkeyspace = heapkeyspace;
2593 andres@anarazel.de 523 : 4005 : state->readonly = readonly;
2206 524 : 4005 : state->heapallindexed = heapallindexed;
1852 pg@bowt.ie 525 : 4005 : state->rootdescend = rootdescend;
169 akorotkov@postgresql 526 :GNC 4005 : state->checkunique = checkunique;
527 : 4005 : state->snapshot = InvalidSnapshot;
528 : :
2206 andres@anarazel.de 529 [ + + ]:CBC 4005 : if (state->heapallindexed)
530 : : {
531 : : int64 total_pages;
532 : : int64 total_elems;
533 : : uint64 seed;
534 : :
535 : : /*
536 : : * Size Bloom filter based on estimated number of tuples in index,
537 : : * while conservatively assuming that each block must contain at least
538 : : * MaxTIDsPerBTreePage / 3 "plain" tuples -- see
539 : : * bt_posting_plain_tuple() for definition, and details of how posting
540 : : * list tuples are handled.
541 : : */
1730 pg@bowt.ie 542 : 83 : total_pages = RelationGetNumberOfBlocks(rel);
1509 543 : 83 : total_elems = Max(total_pages * (MaxTIDsPerBTreePage / 3),
544 : : (int64) state->rel->rd_rel->reltuples);
545 : : /* Generate a random seed to avoid repetition */
868 tgl@sss.pgh.pa.us 546 : 83 : seed = pg_prng_uint64(&pg_global_prng_state);
547 : : /* Create Bloom filter to fingerprint index */
2206 andres@anarazel.de 548 : 83 : state->filter = bloom_create(total_elems, maintenance_work_mem, seed);
549 : 83 : state->heaptuplespresent = 0;
550 : :
551 : : /*
552 : : * Register our own snapshot in !readonly case, rather than asking
553 : : * table_index_build_scan() to do this for us later. This needs to
554 : : * happen before index fingerprinting begins, so we can later be
555 : : * certain that index fingerprinting should have reached all tuples
556 : : * returned by table_index_build_scan().
557 : : */
558 [ + + ]: 83 : if (!state->readonly)
559 : : {
560 : 56 : snapshot = RegisterSnapshot(GetTransactionSnapshot());
561 : :
562 : : /*
563 : : * GetTransactionSnapshot() always acquires a new MVCC snapshot in
564 : : * READ COMMITTED mode. A new snapshot is guaranteed to have all
565 : : * the entries it requires in the index.
566 : : *
567 : : * We must defend against the possibility that an old xact
568 : : * snapshot was returned at higher isolation levels when that
569 : : * snapshot is not safe for index scans of the target index. This
570 : : * is possible when the snapshot sees tuples that are before the
571 : : * index's indcheckxmin horizon. Throwing an error here should be
572 : : * very rare. It doesn't seem worth using a secondary snapshot to
573 : : * avoid this.
574 : : */
575 [ - + - - ]: 56 : if (IsolationUsesXactSnapshot() && rel->rd_index->indcheckxmin &&
2206 andres@anarazel.de 576 [ # # # # ]:UBC 0 : !TransactionIdPrecedes(HeapTupleHeaderGetXmin(rel->rd_indextuple->t_data),
577 : : snapshot->xmin))
578 [ # # ]: 0 : ereport(ERROR,
579 : : (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
580 : : errmsg("index \"%s\" cannot be verified using transaction snapshot",
581 : : RelationGetRelationName(rel))));
582 : : }
583 : : }
584 : :
585 : : /*
586 : : * We need a snapshot to check the uniqueness of the index. For better
587 : : * performance take it once per index check. If snapshot already taken
588 : : * reuse it.
589 : : */
169 akorotkov@postgresql 590 [ + + ]:GNC 4005 : if (state->checkunique)
591 : : {
592 : 708 : state->indexinfo = BuildIndexInfo(state->rel);
593 [ + + ]: 708 : if (state->indexinfo->ii_Unique)
594 : : {
595 [ + + ]: 638 : if (snapshot != SnapshotAny)
596 : 7 : state->snapshot = snapshot;
597 : : else
598 : 631 : state->snapshot = RegisterSnapshot(GetTransactionSnapshot());
599 : : }
600 : : }
601 : :
1852 pg@bowt.ie 602 [ + + - + ]:CBC 4005 : Assert(!state->rootdescend || state->readonly);
603 [ + + - + ]: 4005 : if (state->rootdescend && !state->heapkeyspace)
1852 pg@bowt.ie 604 [ # # ]:UBC 0 : ereport(ERROR,
605 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
606 : : errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
607 : : RelationGetRelationName(rel)),
608 : : errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
609 : :
610 : : /* Create context for page */
2593 andres@anarazel.de 611 :CBC 4005 : state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
612 : : "amcheck context",
613 : : ALLOCSET_DEFAULT_SIZES);
614 : 4005 : state->checkstrategy = GetAccessStrategy(BAS_BULKREAD);
615 : :
616 : : /* Get true root block from meta-page */
617 : 4005 : metapage = palloc_btree_page(state, BTREE_METAPAGE);
618 : 4005 : metad = BTPageGetMeta(metapage);
619 : :
620 : : /*
621 : : * Certain deletion patterns can result in "skinny" B-Tree indexes, where
622 : : * the fast root and true root differ.
623 : : *
624 : : * Start from the true root, not the fast root, unlike conventional index
625 : : * scans. This approach is more thorough, and removes the risk of
626 : : * following a stale fast root from the meta page.
627 : : */
628 [ + + ]: 4005 : if (metad->btm_fastroot != metad->btm_root)
629 [ - + ]: 13 : ereport(DEBUG1,
630 : : (errcode(ERRCODE_NO_DATA),
631 : : errmsg_internal("harmless fast root mismatch in index \"%s\"",
632 : : RelationGetRelationName(rel)),
633 : : errdetail_internal("Fast root block %u (level %u) differs from true root block %u (level %u).",
634 : : metad->btm_fastroot, metad->btm_fastlevel,
635 : : metad->btm_root, metad->btm_level)));
636 : :
637 : : /*
638 : : * Starting at the root, verify every level. Move left to right, top to
639 : : * bottom. Note that there may be no pages other than the meta page (meta
640 : : * page can indicate that root is P_NONE when the index is totally empty).
641 : : */
642 : 4005 : previouslevel = InvalidBtreeLevel;
643 : 4005 : current.level = metad->btm_level;
644 : 4005 : current.leftmost = metad->btm_root;
645 : 4005 : current.istruerootlevel = true;
646 [ + + ]: 6464 : while (current.leftmost != P_NONE)
647 : : {
648 : : /*
649 : : * Verify this level, and get left most page for next level down, if
650 : : * not at leaf level
651 : : */
652 : 2477 : current = bt_check_level_from_leftmost(state, current);
653 : :
654 [ - + ]: 2459 : if (current.leftmost == InvalidBlockNumber)
2593 andres@anarazel.de 655 [ # # ]:UBC 0 : ereport(ERROR,
656 : : (errcode(ERRCODE_INDEX_CORRUPTED),
657 : : errmsg("index \"%s\" has no valid pages on level below %u or first level",
658 : : RelationGetRelationName(rel), previouslevel)));
659 : :
2593 andres@anarazel.de 660 :CBC 2459 : previouslevel = current.level;
661 : : }
662 : :
663 : : /*
664 : : * * Check whether heap contains unindexed/malformed tuples *
665 : : */
2206 666 [ + + ]: 3987 : if (state->heapallindexed)
667 : : {
668 : 76 : IndexInfo *indexinfo = BuildIndexInfo(state->rel);
669 : : TableScanDesc scan;
670 : :
671 : : /*
672 : : * Create our own scan for table_index_build_scan(), rather than
673 : : * getting it to do so for us. This is required so that we can
674 : : * actually use the MVCC snapshot registered earlier in !readonly
675 : : * case.
676 : : *
677 : : * Note that table_index_build_scan() calls heap_endscan() for us.
678 : : */
1845 679 : 76 : scan = table_beginscan_strat(state->heaprel, /* relation */
680 : : snapshot, /* snapshot */
681 : : 0, /* number of keys */
682 : : NULL, /* scan key */
683 : : true, /* buffer access strategy OK */
684 : : true); /* syncscan OK? */
685 : :
686 : : /*
687 : : * Scan will behave as the first scan of a CREATE INDEX CONCURRENTLY
688 : : * behaves in !readonly case.
689 : : *
690 : : * It's okay that we don't actually use the same lock strength for the
691 : : * heap relation as any other ii_Concurrent caller would in !readonly
692 : : * case. We have no reason to care about a concurrent VACUUM
693 : : * operation, since there isn't going to be a second scan of the heap
694 : : * that needs to be sure that there was no concurrent recycling of
695 : : * TIDs.
696 : : */
2206 697 : 74 : indexinfo->ii_Concurrent = !state->readonly;
698 : :
699 : : /*
700 : : * Don't wait for uncommitted tuple xact commit/abort when index is a
701 : : * unique index on a catalog (or an index used by an exclusion
702 : : * constraint). This could otherwise happen in the readonly case.
703 : : */
704 : 74 : indexinfo->ii_Unique = false;
705 : 74 : indexinfo->ii_ExclusionOps = NULL;
706 : 74 : indexinfo->ii_ExclusionProcs = NULL;
707 : 74 : indexinfo->ii_ExclusionStrats = NULL;
708 : :
709 [ + + ]: 74 : elog(DEBUG1, "verifying that tuples from index \"%s\" are present in \"%s\"",
710 : : RelationGetRelationName(state->rel),
711 : : RelationGetRelationName(state->heaprel));
712 : :
1839 alvherre@alvh.no-ip. 713 : 74 : table_index_build_scan(state->heaprel, state->rel, indexinfo, true, false,
714 : : bt_tuple_present_callback, (void *) state, scan);
715 : :
2206 andres@anarazel.de 716 [ + + ]: 74 : ereport(DEBUG1,
717 : : (errmsg_internal("finished verifying presence of " INT64_FORMAT " tuples from table \"%s\" with bitset %.2f%% set",
718 : : state->heaptuplespresent, RelationGetRelationName(heaprel),
719 : : 100.0 * bloom_prop_bits_set(state->filter))));
720 : :
721 [ + + ]: 74 : if (snapshot != SnapshotAny)
722 : 51 : UnregisterSnapshot(snapshot);
723 : :
724 : 74 : bloom_free(state->filter);
725 : : }
726 : :
727 : : /* Be tidy: */
169 akorotkov@postgresql 728 [ + + + + ]:GNC 3985 : if (snapshot == SnapshotAny && state->snapshot != InvalidSnapshot)
729 : 631 : UnregisterSnapshot(state->snapshot);
2593 andres@anarazel.de 730 :CBC 3985 : MemoryContextDelete(state->targetcontext);
731 : 3985 : }
732 : :
733 : : /*
734 : : * Given a left-most block at some level, move right, verifying each page
735 : : * individually (with more verification across pages for "readonly"
736 : : * callers). Caller should pass the true root page as the leftmost initially,
737 : : * working their way down by passing what is returned for the last call here
738 : : * until level 0 (leaf page level) was reached.
739 : : *
740 : : * Returns state for next call, if any. This includes left-most block number
741 : : * one level lower that should be passed on next level/call, which is set to
742 : : * P_NONE on last call here (when leaf level is verified). Level numbers
743 : : * follow the nbtree convention: higher levels have higher numbers, because new
744 : : * levels are added only due to a root page split. Note that prior to the
745 : : * first root page split, the root is also a leaf page, so there is always a
746 : : * level 0 (leaf level), and it's always the last level processed.
747 : : *
748 : : * Note on memory management: State's per-page context is reset here, between
749 : : * each call to bt_target_page_check().
750 : : */
751 : : static BtreeLevel
752 : 2477 : bt_check_level_from_leftmost(BtreeCheckState *state, BtreeLevel level)
753 : : {
754 : : /* State to establish early, concerning entire level */
755 : : BTPageOpaque opaque;
756 : : MemoryContext oldcontext;
757 : : BtreeLevel nextleveldown;
758 : :
759 : : /* Variables for iterating across level using right links */
760 : 2477 : BlockNumber leftcurrent = P_NONE;
761 : 2477 : BlockNumber current = level.leftmost;
762 : :
763 : : /* Initialize return state */
764 : 2477 : nextleveldown.leftmost = InvalidBlockNumber;
765 : 2477 : nextleveldown.level = InvalidBtreeLevel;
766 : 2477 : nextleveldown.istruerootlevel = false;
767 : :
768 : : /* Use page-level context for duration of this call */
769 : 2477 : oldcontext = MemoryContextSwitchTo(state->targetcontext);
770 : :
1465 pg@bowt.ie 771 [ + + + + : 2477 : elog(DEBUG1, "verifying level %u%s", level.level,
+ - ]
772 : : level.istruerootlevel ?
773 : : " (true root level)" : level.level == 0 ? " (leaf level)" : "");
774 : :
1495 akorotkov@postgresql 775 : 2477 : state->prevrightlink = InvalidBlockNumber;
776 : 2477 : state->previncompletesplit = false;
777 : :
778 : : do
779 : : {
780 : : /* Don't rely on CHECK_FOR_INTERRUPTS() calls at lower level */
2593 andres@anarazel.de 781 [ - + ]: 9092 : CHECK_FOR_INTERRUPTS();
782 : :
783 : : /* Initialize state for this iteration */
784 : 9092 : state->targetblock = current;
785 : 9092 : state->target = palloc_btree_page(state, state->targetblock);
786 : 9080 : state->targetlsn = PageGetLSN(state->target);
787 : :
744 michael@paquier.xyz 788 : 9080 : opaque = BTPageGetOpaque(state->target);
789 : :
2593 andres@anarazel.de 790 [ - + ]: 9080 : if (P_IGNORE(opaque))
791 : : {
792 : : /*
793 : : * Since there cannot be a concurrent VACUUM operation in readonly
794 : : * mode, and since a page has no links within other pages
795 : : * (siblings and parent) once it is marked fully deleted, it
796 : : * should be impossible to land on a fully deleted page in
797 : : * readonly mode. See bt_child_check() for further details.
798 : : *
799 : : * The bt_child_check() P_ISDELETED() check is repeated here so
800 : : * that pages that are only reachable through sibling links get
801 : : * checked.
802 : : */
2181 teodor@sigaev.ru 803 [ # # # # ]:UBC 0 : if (state->readonly && P_ISDELETED(opaque))
804 [ # # ]: 0 : ereport(ERROR,
805 : : (errcode(ERRCODE_INDEX_CORRUPTED),
806 : : errmsg("downlink or sibling link points to deleted block in index \"%s\"",
807 : : RelationGetRelationName(state->rel)),
808 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
809 : : current, leftcurrent, opaque->btpo_prev)));
810 : :
2593 andres@anarazel.de 811 [ # # ]: 0 : if (P_RIGHTMOST(opaque))
812 [ # # ]: 0 : ereport(ERROR,
813 : : (errcode(ERRCODE_INDEX_CORRUPTED),
814 : : errmsg("block %u fell off the end of index \"%s\"",
815 : : current, RelationGetRelationName(state->rel))));
816 : : else
817 [ # # ]: 0 : ereport(DEBUG1,
818 : : (errcode(ERRCODE_NO_DATA),
819 : : errmsg_internal("block %u of index \"%s\" concurrently deleted",
820 : : current, RelationGetRelationName(state->rel))));
821 : 0 : goto nextpage;
822 : : }
2593 andres@anarazel.de 823 [ + + ]:CBC 9080 : else if (nextleveldown.leftmost == InvalidBlockNumber)
824 : : {
825 : : /*
826 : : * A concurrent page split could make the caller supplied leftmost
827 : : * block no longer contain the leftmost page, or no longer be the
828 : : * true root, but where that isn't possible due to heavyweight
829 : : * locking, check that the first valid page meets caller's
830 : : * expectations.
831 : : */
832 [ + + ]: 2465 : if (state->readonly)
833 : : {
167 noah@leadboat.com 834 [ - + ]: 44 : if (!bt_leftmost_ignoring_half_dead(state, current, opaque))
2593 andres@anarazel.de 835 [ # # ]:UBC 0 : ereport(ERROR,
836 : : (errcode(ERRCODE_INDEX_CORRUPTED),
837 : : errmsg("block %u is not leftmost in index \"%s\"",
838 : : current, RelationGetRelationName(state->rel))));
839 : :
2593 andres@anarazel.de 840 [ + + - + ]:CBC 44 : if (level.istruerootlevel && !P_ISROOT(opaque))
2593 andres@anarazel.de 841 [ # # ]:UBC 0 : ereport(ERROR,
842 : : (errcode(ERRCODE_INDEX_CORRUPTED),
843 : : errmsg("block %u is not true root in index \"%s\"",
844 : : current, RelationGetRelationName(state->rel))));
845 : : }
846 : :
847 : : /*
848 : : * Before beginning any non-trivial examination of level, prepare
849 : : * state for next bt_check_level_from_leftmost() invocation for
850 : : * the next level for the next level down (if any).
851 : : *
852 : : * There should be at least one non-ignorable page per level,
853 : : * unless this is the leaf level, which is assumed by caller to be
854 : : * final level.
855 : : */
2593 andres@anarazel.de 856 [ + + ]:CBC 2465 : if (!P_ISLEAF(opaque))
857 : : {
858 : : IndexTuple itup;
859 : : ItemId itemid;
860 : :
861 : : /* Internal page -- downlink gets leftmost on next level */
1816 pg@bowt.ie 862 : 513 : itemid = PageGetItemIdCareful(state, state->targetblock,
863 : : state->target,
864 [ + + ]: 513 : P_FIRSTDATAKEY(opaque));
2593 andres@anarazel.de 865 : 513 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1581 pg@bowt.ie 866 : 513 : nextleveldown.leftmost = BTreeTupleGetDownLink(itup);
1145 867 : 513 : nextleveldown.level = opaque->btpo_level - 1;
868 : : }
869 : : else
870 : : {
871 : : /*
872 : : * Leaf page -- final level caller must process.
873 : : *
874 : : * Note that this could also be the root page, if there has
875 : : * been no root page split yet.
876 : : */
2593 andres@anarazel.de 877 : 1952 : nextleveldown.leftmost = P_NONE;
878 : 1952 : nextleveldown.level = InvalidBtreeLevel;
879 : : }
880 : :
881 : : /*
882 : : * Finished setting up state for this call/level. Control will
883 : : * never end up back here in any future loop iteration for this
884 : : * level.
885 : : */
886 : : }
887 : :
888 : : /*
889 : : * Sibling links should be in mutual agreement. There arises
890 : : * leftcurrent == P_NONE && btpo_prev != P_NONE when the left sibling
891 : : * of the parent's low-key downlink is half-dead. (A half-dead page
892 : : * has no downlink from its parent.) Under heavyweight locking, the
893 : : * last bt_leftmost_ignoring_half_dead() validated this btpo_prev.
894 : : * Without heavyweight locking, validation of the P_NONE case remains
895 : : * unimplemented.
896 : : */
167 noah@leadboat.com 897 [ + + - + ]: 9080 : if (opaque->btpo_prev != leftcurrent && leftcurrent != P_NONE)
1345 pg@bowt.ie 898 :UBC 0 : bt_recheck_sibling_links(state, opaque->btpo_prev, leftcurrent);
899 : :
900 : : /* Check level */
1145 pg@bowt.ie 901 [ - + ]:CBC 9080 : if (level.level != opaque->btpo_level)
2593 andres@anarazel.de 902 [ # # ]:UBC 0 : ereport(ERROR,
903 : : (errcode(ERRCODE_INDEX_CORRUPTED),
904 : : errmsg("leftmost down link for level points to block in index \"%s\" whose level is not one level down",
905 : : RelationGetRelationName(state->rel)),
906 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
907 : : current, level.level, opaque->btpo_level)));
908 : :
909 : : /* Verify invariants for page */
2593 andres@anarazel.de 910 :CBC 9080 : bt_target_page_check(state);
911 : :
912 : 9074 : nextpage:
913 : :
914 : : /* Try to detect circular links */
915 [ + - - + ]: 9074 : if (current == leftcurrent || current == opaque->btpo_prev)
2593 andres@anarazel.de 916 [ # # ]:UBC 0 : ereport(ERROR,
917 : : (errcode(ERRCODE_INDEX_CORRUPTED),
918 : : errmsg("circular link chain found in block %u of index \"%s\"",
919 : : current, RelationGetRelationName(state->rel))));
920 : :
1495 akorotkov@postgresql 921 :CBC 9074 : leftcurrent = current;
922 : 9074 : current = opaque->btpo_next;
923 : :
924 [ + + ]: 9074 : if (state->lowkey)
925 : : {
926 [ - + ]: 1862 : Assert(state->readonly);
927 : 1862 : pfree(state->lowkey);
928 : 1862 : state->lowkey = NULL;
929 : : }
930 : :
931 : : /*
932 : : * Copy current target high key as the low key of right sibling.
933 : : * Allocate memory in upper level context, so it would be cleared
934 : : * after reset of target context.
935 : : *
936 : : * We only need the low key in corner cases of checking child high
937 : : * keys. We use high key only when incomplete split on the child level
938 : : * falls to the boundary of pages on the target level. See
939 : : * bt_child_highkey_check() for details. So, typically we won't end
940 : : * up doing anything with low key, but it's simpler for general case
941 : : * high key verification to always have it available.
942 : : *
943 : : * The correctness of managing low key in the case of concurrent
944 : : * splits wasn't investigated yet. Thankfully we only need low key
945 : : * for readonly verification and concurrent splits won't happen.
946 : : */
947 [ + + + + ]: 9074 : if (state->readonly && !P_RIGHTMOST(opaque))
948 : : {
949 : : IndexTuple itup;
950 : : ItemId itemid;
951 : :
952 : 1862 : itemid = PageGetItemIdCareful(state, state->targetblock,
953 : : state->target, P_HIKEY);
954 : 1862 : itup = (IndexTuple) PageGetItem(state->target, itemid);
955 : :
956 : 1862 : state->lowkey = MemoryContextAlloc(oldcontext, IndexTupleSize(itup));
957 : 1862 : memcpy(state->lowkey, itup, IndexTupleSize(itup));
958 : : }
959 : :
960 : : /* Free page and associated memory for this iteration */
2593 andres@anarazel.de 961 : 9074 : MemoryContextReset(state->targetcontext);
962 : : }
963 [ + + ]: 9074 : while (current != P_NONE);
964 : :
1495 akorotkov@postgresql 965 [ - + ]: 2459 : if (state->lowkey)
966 : : {
1495 akorotkov@postgresql 967 [ # # ]:UBC 0 : Assert(state->readonly);
968 : 0 : pfree(state->lowkey);
969 : 0 : state->lowkey = NULL;
970 : : }
971 : :
972 : : /* Don't change context for caller */
2593 andres@anarazel.de 973 :CBC 2459 : MemoryContextSwitchTo(oldcontext);
974 : :
975 : 2459 : return nextleveldown;
976 : : }
977 : :
978 : : /* Check visibility of the table entry referenced by nbtree index */
979 : : static bool
169 akorotkov@postgresql 980 :GNC 144902 : heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid)
981 : : {
982 : : bool tid_visible;
983 : :
984 : 144902 : TupleTableSlot *slot = table_slot_create(state->heaprel, NULL);
985 : :
986 : 144902 : tid_visible = table_tuple_fetch_row_version(state->heaprel,
987 : : tid, state->snapshot, slot);
988 [ + - ]: 144902 : if (slot != NULL)
989 : 144902 : ExecDropSingleTupleTableSlot(slot);
990 : :
991 : 144902 : return tid_visible;
992 : : }
993 : :
994 : : /*
995 : : * Prepare an error message for unique constrain violation in
996 : : * a btree index and report ERROR.
997 : : */
998 : : static void
999 : 3 : bt_report_duplicate(BtreeCheckState *state,
1000 : : ItemPointer tid, BlockNumber block, OffsetNumber offset,
1001 : : int posting,
1002 : : ItemPointer nexttid, BlockNumber nblock, OffsetNumber noffset,
1003 : : int nposting)
1004 : : {
1005 : : char *htid,
1006 : : *nhtid,
1007 : : *itid,
1008 : 3 : *nitid = "",
1009 : 3 : *pposting = "",
1010 : 3 : *pnposting = "";
1011 : :
1012 : 3 : htid = psprintf("tid=(%u,%u)",
1013 : : ItemPointerGetBlockNumberNoCheck(tid),
1014 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
1015 : 3 : nhtid = psprintf("tid=(%u,%u)",
1016 : : ItemPointerGetBlockNumberNoCheck(nexttid),
1017 : 3 : ItemPointerGetOffsetNumberNoCheck(nexttid));
1018 : 3 : itid = psprintf("tid=(%u,%u)", block, offset);
1019 : :
1020 [ + - + - ]: 3 : if (nblock != block || noffset != offset)
1021 : 3 : nitid = psprintf(" tid=(%u,%u)", nblock, noffset);
1022 : :
1023 [ - + ]: 3 : if (posting >= 0)
169 akorotkov@postgresql 1024 :UNC 0 : pposting = psprintf(" posting %u", posting);
1025 : :
169 akorotkov@postgresql 1026 [ - + ]:GNC 3 : if (nposting >= 0)
169 akorotkov@postgresql 1027 :UNC 0 : pnposting = psprintf(" posting %u", nposting);
1028 : :
169 akorotkov@postgresql 1029 [ + - ]:GNC 3 : ereport(ERROR,
1030 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1031 : : errmsg("index uniqueness is violated for index \"%s\"",
1032 : : RelationGetRelationName(state->rel)),
1033 : : errdetail("Index %s%s and%s%s (point to heap %s and %s) page lsn=%X/%X.",
1034 : : itid, pposting, nitid, pnposting, htid, nhtid,
1035 : : LSN_FORMAT_ARGS(state->targetlsn))));
1036 : : }
1037 : :
1038 : : /* Check if current nbtree leaf entry complies with UNIQUE constraint */
1039 : : static void
1040 : 144902 : bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
1041 : : BlockNumber targetblock, OffsetNumber offset, int *lVis_i,
1042 : : ItemPointer *lVis_tid, OffsetNumber *lVis_offset,
1043 : : BlockNumber *lVis_block)
1044 : : {
1045 : : ItemPointer tid;
1046 : 144902 : bool has_visible_entry = false;
1047 : :
1048 [ - + ]: 144902 : Assert(targetblock != P_NONE);
1049 : :
1050 : : /*
1051 : : * Current tuple has posting list. Report duplicate if TID of any posting
1052 : : * list entry is visible and lVis_tid is valid.
1053 : : */
1054 [ - + ]: 144902 : if (BTreeTupleIsPosting(itup))
1055 : : {
169 akorotkov@postgresql 1056 [ # # ]:UNC 0 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
1057 : : {
1058 : 0 : tid = BTreeTupleGetPostingN(itup, i);
1059 [ # # ]: 0 : if (heap_entry_is_visible(state, tid))
1060 : : {
1061 : 0 : has_visible_entry = true;
1062 [ # # ]: 0 : if (ItemPointerIsValid(*lVis_tid))
1063 : : {
1064 : 0 : bt_report_duplicate(state,
1065 : : *lVis_tid, *lVis_block,
1066 : 0 : *lVis_offset, *lVis_i,
1067 : : tid, targetblock,
1068 : : offset, i);
1069 : : }
1070 : :
1071 : : /*
1072 : : * Prevent double reporting unique constraint violation
1073 : : * between the posting list entries of the first tuple on the
1074 : : * page after cross-page check.
1075 : : */
1076 [ # # # # ]: 0 : if (*lVis_block != targetblock && ItemPointerIsValid(*lVis_tid))
1077 : 0 : return;
1078 : :
1079 : 0 : *lVis_i = i;
1080 : 0 : *lVis_tid = tid;
1081 : 0 : *lVis_offset = offset;
1082 : 0 : *lVis_block = targetblock;
1083 : : }
1084 : : }
1085 : : }
1086 : :
1087 : : /*
1088 : : * Current tuple has no posting list. If TID is visible save info about it
1089 : : * for the next comparisons in the loop in bt_page_check(). Report
1090 : : * duplicate if lVis_tid is already valid.
1091 : : */
1092 : : else
1093 : : {
169 akorotkov@postgresql 1094 :GNC 144902 : tid = BTreeTupleGetHeapTID(itup);
1095 [ + + ]: 144902 : if (heap_entry_is_visible(state, tid))
1096 : : {
1097 : 143031 : has_visible_entry = true;
1098 [ + + ]: 143031 : if (ItemPointerIsValid(*lVis_tid))
1099 : : {
1100 : 3 : bt_report_duplicate(state,
1101 : : *lVis_tid, *lVis_block,
1102 : 3 : *lVis_offset, *lVis_i,
1103 : : tid, targetblock,
1104 : : offset, -1);
1105 : : }
1106 : 143028 : *lVis_i = -1;
1107 : 143028 : *lVis_tid = tid;
1108 : 143028 : *lVis_offset = offset;
1109 : 143028 : *lVis_block = targetblock;
1110 : : }
1111 : : }
1112 : :
1113 [ + + - + ]: 144899 : if (!has_visible_entry && *lVis_block != InvalidBlockNumber &&
169 akorotkov@postgresql 1114 [ # # ]:UNC 0 : *lVis_block != targetblock)
1115 : : {
1116 : 0 : char *posting = "";
1117 : :
1118 [ # # ]: 0 : if (*lVis_i >= 0)
1119 : 0 : posting = psprintf(" posting %u", *lVis_i);
1120 [ # # ]: 0 : ereport(DEBUG1,
1121 : : (errcode(ERRCODE_NO_DATA),
1122 : : errmsg("index uniqueness can not be checked for index tid=(%u,%u) in index \"%s\"",
1123 : : targetblock, offset,
1124 : : RelationGetRelationName(state->rel)),
1125 : : errdetail("It doesn't have visible heap tids and key is equal to the tid=(%u,%u)%s (points to heap tid=(%u,%u)).",
1126 : : *lVis_block, *lVis_offset, posting,
1127 : : ItemPointerGetBlockNumberNoCheck(*lVis_tid),
1128 : : ItemPointerGetOffsetNumberNoCheck(*lVis_tid)),
1129 : : errhint("VACUUM the table and repeat the check.")));
1130 : : }
1131 : : }
1132 : :
1133 : : /*
1134 : : * Like P_LEFTMOST(start_opaque), but accept an arbitrarily-long chain of
1135 : : * half-dead, sibling-linked pages to the left. If a half-dead page appears
1136 : : * under state->readonly, the database exited recovery between the first-stage
1137 : : * and second-stage WAL records of a deletion.
1138 : : */
1139 : : static bool
167 noah@leadboat.com 1140 :CBC 55 : bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
1141 : : BlockNumber start,
1142 : : BTPageOpaque start_opaque)
1143 : : {
1144 : 55 : BlockNumber reached = start_opaque->btpo_prev,
1145 : 55 : reached_from = start;
1146 : 55 : bool all_half_dead = true;
1147 : :
1148 : : /*
1149 : : * To handle the !readonly case, we'd need to accept BTP_DELETED pages and
1150 : : * potentially observe nbtree/README "Page deletion and backwards scans".
1151 : : */
1152 [ - + ]: 55 : Assert(state->readonly);
1153 : :
1154 [ + + + - ]: 57 : while (reached != P_NONE && all_half_dead)
1155 : : {
1156 : 2 : Page page = palloc_btree_page(state, reached);
1157 : 2 : BTPageOpaque reached_opaque = BTPageGetOpaque(page);
1158 : :
1159 [ - + ]: 2 : CHECK_FOR_INTERRUPTS();
1160 : :
1161 : : /*
1162 : : * Try to detect btpo_prev circular links. _bt_unlink_halfdead_page()
1163 : : * writes that side-links will continue to point to the siblings.
1164 : : * Check btpo_next for that property.
1165 : : */
1166 [ + - ]: 2 : all_half_dead = P_ISHALFDEAD(reached_opaque) &&
1167 [ + - ]: 2 : reached != start &&
1168 [ + - ]: 4 : reached != reached_from &&
1169 [ + - ]: 2 : reached_opaque->btpo_next == reached_from;
1170 [ + - ]: 2 : if (all_half_dead)
1171 : : {
1172 : 2 : XLogRecPtr pagelsn = PageGetLSN(page);
1173 : :
1174 : : /* pagelsn should point to an XLOG_BTREE_MARK_PAGE_HALFDEAD */
1175 [ + - ]: 2 : ereport(DEBUG1,
1176 : : (errcode(ERRCODE_NO_DATA),
1177 : : errmsg_internal("harmless interrupted page deletion detected in index \"%s\"",
1178 : : RelationGetRelationName(state->rel)),
1179 : : errdetail_internal("Block=%u right block=%u page lsn=%X/%X.",
1180 : : reached, reached_from,
1181 : : LSN_FORMAT_ARGS(pagelsn))));
1182 : :
1183 : 2 : reached_from = reached;
1184 : 2 : reached = reached_opaque->btpo_prev;
1185 : : }
1186 : :
1187 : 2 : pfree(page);
1188 : : }
1189 : :
1190 : 55 : return all_half_dead;
1191 : : }
1192 : :
1193 : : /*
1194 : : * Raise an error when target page's left link does not point back to the
1195 : : * previous target page, called leftcurrent here. The leftcurrent page's
1196 : : * right link was followed to get to the current target page, and we expect
1197 : : * mutual agreement among leftcurrent and the current target page. Make sure
1198 : : * that this condition has definitely been violated in the !readonly case,
1199 : : * where concurrent page splits are something that we need to deal with.
1200 : : *
1201 : : * Cross-page inconsistencies involving pages that don't agree about being
1202 : : * siblings are known to be a particularly good indicator of corruption
1203 : : * involving partial writes/lost updates. The bt_right_page_check_scankey
1204 : : * check also provides a way of detecting cross-page inconsistencies for
1205 : : * !readonly callers, but it can only detect sibling pages that have an
1206 : : * out-of-order keyspace, which can't catch many of the problems that we
1207 : : * expect to catch here.
1208 : : *
1209 : : * The classic example of the kind of inconsistency that we can only catch
1210 : : * with this check (when in !readonly mode) involves three sibling pages that
1211 : : * were affected by a faulty page split at some point in the past. The
1212 : : * effects of the split are reflected in the original page and its new right
1213 : : * sibling page, with a lack of any accompanying changes for the _original_
1214 : : * right sibling page. The original right sibling page's left link fails to
1215 : : * point to the new right sibling page (its left link still points to the
1216 : : * original page), even though the first phase of a page split is supposed to
1217 : : * work as a single atomic action. This subtle inconsistency will probably
1218 : : * only break backwards scans in practice.
1219 : : *
1220 : : * Note that this is the only place where amcheck will "couple" buffer locks
1221 : : * (and only for !readonly callers). In general we prefer to avoid more
1222 : : * thorough cross-page checks in !readonly mode, but it seems worth the
1223 : : * complexity here. Also, the performance overhead of performing lock
1224 : : * coupling here is negligible in practice. Control only reaches here with a
1225 : : * non-corrupt index when there is a concurrent page split at the instant
1226 : : * caller crossed over to target page from leftcurrent page.
1227 : : */
1228 : : static void
1345 pg@bowt.ie 1229 :UBC 0 : bt_recheck_sibling_links(BtreeCheckState *state,
1230 : : BlockNumber btpo_prev_from_target,
1231 : : BlockNumber leftcurrent)
1232 : : {
1233 : : /* passing metapage to BTPageGetOpaque() would give irrelevant findings */
167 noah@leadboat.com 1234 [ # # ]: 0 : Assert(leftcurrent != P_NONE);
1235 : :
1345 pg@bowt.ie 1236 [ # # ]: 0 : if (!state->readonly)
1237 : : {
1238 : : Buffer lbuf;
1239 : : Buffer newtargetbuf;
1240 : : Page page;
1241 : : BTPageOpaque opaque;
1242 : : BlockNumber newtargetblock;
1243 : :
1244 : : /* Couple locks in the usual order for nbtree: Left to right */
1245 : 0 : lbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM, leftcurrent,
1246 : : RBM_NORMAL, state->checkstrategy);
1247 : 0 : LockBuffer(lbuf, BT_READ);
1248 : 0 : _bt_checkpage(state->rel, lbuf);
1249 : 0 : page = BufferGetPage(lbuf);
744 michael@paquier.xyz 1250 : 0 : opaque = BTPageGetOpaque(page);
1345 pg@bowt.ie 1251 [ # # ]: 0 : if (P_ISDELETED(opaque))
1252 : : {
1253 : : /*
1254 : : * Cannot reason about concurrently deleted page -- the left link
1255 : : * in the page to the right is expected to point to some other
1256 : : * page to the left (not leftcurrent page).
1257 : : *
1258 : : * Note that we deliberately don't give up with a half-dead page.
1259 : : */
1260 : 0 : UnlockReleaseBuffer(lbuf);
1261 : 0 : return;
1262 : : }
1263 : :
1264 : 0 : newtargetblock = opaque->btpo_next;
1265 : : /* Avoid self-deadlock when newtargetblock == leftcurrent */
1266 [ # # ]: 0 : if (newtargetblock != leftcurrent)
1267 : : {
1268 : 0 : newtargetbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM,
1269 : : newtargetblock, RBM_NORMAL,
1270 : : state->checkstrategy);
1271 : 0 : LockBuffer(newtargetbuf, BT_READ);
1272 : 0 : _bt_checkpage(state->rel, newtargetbuf);
1273 : 0 : page = BufferGetPage(newtargetbuf);
744 michael@paquier.xyz 1274 : 0 : opaque = BTPageGetOpaque(page);
1275 : : /* btpo_prev_from_target may have changed; update it */
1345 pg@bowt.ie 1276 : 0 : btpo_prev_from_target = opaque->btpo_prev;
1277 : : }
1278 : : else
1279 : : {
1280 : : /*
1281 : : * leftcurrent right sibling points back to leftcurrent block.
1282 : : * Index is corrupt. Easiest way to handle this is to pretend
1283 : : * that we actually read from a distinct page that has an invalid
1284 : : * block number in its btpo_prev.
1285 : : */
1286 : 0 : newtargetbuf = InvalidBuffer;
1287 : 0 : btpo_prev_from_target = InvalidBlockNumber;
1288 : : }
1289 : :
1290 : : /*
1291 : : * No need to check P_ISDELETED here, since new target block cannot be
1292 : : * marked deleted as long as we hold a lock on lbuf
1293 : : */
1294 [ # # ]: 0 : if (BufferIsValid(newtargetbuf))
1295 : 0 : UnlockReleaseBuffer(newtargetbuf);
1296 : 0 : UnlockReleaseBuffer(lbuf);
1297 : :
1298 [ # # ]: 0 : if (btpo_prev_from_target == leftcurrent)
1299 : : {
1300 : : /* Report split in left sibling, not target (or new target) */
1301 [ # # ]: 0 : ereport(DEBUG1,
1302 : : (errcode(ERRCODE_INTERNAL_ERROR),
1303 : : errmsg_internal("harmless concurrent page split detected in index \"%s\"",
1304 : : RelationGetRelationName(state->rel)),
1305 : : errdetail_internal("Block=%u new right sibling=%u original right sibling=%u.",
1306 : : leftcurrent, newtargetblock,
1307 : : state->targetblock)));
1308 : 0 : return;
1309 : : }
1310 : :
1311 : : /*
1312 : : * Index is corrupt. Make sure that we report correct target page.
1313 : : *
1314 : : * This could have changed in cases where there was a concurrent page
1315 : : * split, as well as index corruption (at least in theory). Note that
1316 : : * btpo_prev_from_target was already updated above.
1317 : : */
1318 : 0 : state->targetblock = newtargetblock;
1319 : : }
1320 : :
1321 [ # # ]: 0 : ereport(ERROR,
1322 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1323 : : errmsg("left link/right link pair in index \"%s\" not in agreement",
1324 : : RelationGetRelationName(state->rel)),
1325 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
1326 : : state->targetblock, leftcurrent,
1327 : : btpo_prev_from_target)));
1328 : : }
1329 : :
1330 : : /*
1331 : : * Function performs the following checks on target page, or pages ancillary to
1332 : : * target page:
1333 : : *
1334 : : * - That every "real" data item is less than or equal to the high key, which
1335 : : * is an upper bound on the items on the page. Data items should be
1336 : : * strictly less than the high key when the page is an internal page.
1337 : : *
1338 : : * - That within the page, every data item is strictly less than the item
1339 : : * immediately to its right, if any (i.e., that the items are in order
1340 : : * within the page, so that the binary searches performed by index scans are
1341 : : * sane).
1342 : : *
1343 : : * - That the last data item stored on the page is strictly less than the
1344 : : * first data item on the page to the right (when such a first item is
1345 : : * available).
1346 : : *
1347 : : * - Various checks on the structure of tuples themselves. For example, check
1348 : : * that non-pivot tuples have no truncated attributes.
1349 : : *
1350 : : * - For index with unique constraint make sure that only one of table entries
1351 : : * for equal keys is visible.
1352 : : *
1353 : : * Furthermore, when state passed shows ShareLock held, function also checks:
1354 : : *
1355 : : * - That all child pages respect strict lower bound from parent's pivot
1356 : : * tuple.
1357 : : *
1358 : : * - That downlink to block was encountered in parent where that's expected.
1359 : : *
1360 : : * - That high keys of child pages matches corresponding pivot keys in parent.
1361 : : *
1362 : : * This is also where heapallindexed callers use their Bloom filter to
1363 : : * fingerprint IndexTuples for later table_index_build_scan() verification.
1364 : : *
1365 : : * Note: Memory allocated in this routine is expected to be released by caller
1366 : : * resetting state->targetcontext.
1367 : : */
1368 : : static void
2593 andres@anarazel.de 1369 :CBC 9080 : bt_target_page_check(BtreeCheckState *state)
1370 : : {
1371 : : OffsetNumber offset;
1372 : : OffsetNumber max;
1373 : : BTPageOpaque topaque;
1374 : :
1375 : : /* last visible entry info for checking indexes with unique constraint */
169 akorotkov@postgresql 1376 :GNC 9080 : int lVis_i = -1; /* the position of last visible item for
1377 : : * posting tuple. for non-posting tuple (-1) */
1378 : 9080 : ItemPointer lVis_tid = NULL;
1379 : 9080 : BlockNumber lVis_block = InvalidBlockNumber;
1380 : 9080 : OffsetNumber lVis_offset = InvalidOffsetNumber;
1381 : :
744 michael@paquier.xyz 1382 :CBC 9080 : topaque = BTPageGetOpaque(state->target);
2593 andres@anarazel.de 1383 : 9080 : max = PageGetMaxOffsetNumber(state->target);
1384 : :
1385 [ - + - - ]: 9080 : elog(DEBUG2, "verifying %u items on %s block %u", max,
1386 : : P_ISLEAF(topaque) ? "leaf" : "internal", state->targetblock);
1387 : :
1388 : : /*
1389 : : * Check the number of attributes in high key. Note, rightmost page
1390 : : * doesn't contain a high key, so nothing to check
1391 : : */
1816 pg@bowt.ie 1392 [ + + ]: 9080 : if (!P_RIGHTMOST(topaque))
1393 : : {
1394 : : ItemId itemid;
1395 : : IndexTuple itup;
1396 : :
1397 : : /* Verify line pointer before checking tuple */
1398 : 6619 : itemid = PageGetItemIdCareful(state, state->targetblock,
1399 : : state->target, P_HIKEY);
1400 [ - + ]: 6619 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1401 : : P_HIKEY))
1402 : : {
1816 pg@bowt.ie 1403 :UBC 0 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1404 [ # # # # : 0 : ereport(ERROR,
# # ]
1405 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1406 : : errmsg("wrong number of high key index tuple attributes in index \"%s\"",
1407 : : RelationGetRelationName(state->rel)),
1408 : : errdetail_internal("Index block=%u natts=%u block type=%s page lsn=%X/%X.",
1409 : : state->targetblock,
1410 : : BTreeTupleGetNAtts(itup, state->rel),
1411 : : P_ISLEAF(topaque) ? "heap" : "index",
1412 : : LSN_FORMAT_ARGS(state->targetlsn))));
1413 : : }
1414 : : }
1415 : :
1416 : : /*
1417 : : * Loop over page items, starting from first non-highkey item, not high
1418 : : * key (if any). Most tests are not performed for the "negative infinity"
1419 : : * real item (if any).
1420 : : */
2593 andres@anarazel.de 1421 [ + + ]:CBC 9080 : for (offset = P_FIRSTDATAKEY(topaque);
1422 [ + + ]: 2028138 : offset <= max;
1423 : 2019058 : offset = OffsetNumberNext(offset))
1424 : : {
1425 : : ItemId itemid;
1426 : : IndexTuple itup;
1427 : : size_t tupsize;
1428 : : BTScanInsert skey;
1429 : : bool lowersizelimit;
1430 : : ItemPointer scantid;
1431 : :
1432 [ - + ]: 2019064 : CHECK_FOR_INTERRUPTS();
1433 : :
1816 pg@bowt.ie 1434 : 2019064 : itemid = PageGetItemIdCareful(state, state->targetblock,
1435 : : state->target, offset);
2206 andres@anarazel.de 1436 : 2019064 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1437 : 2019064 : tupsize = IndexTupleSize(itup);
1438 : :
1439 : : /*
1440 : : * lp_len should match the IndexTuple reported length exactly, since
1441 : : * lp_len is completely redundant in indexes, and both sources of
1442 : : * tuple length are MAXALIGN()'d. nbtree does not use lp_len all that
1443 : : * frequently, and is surprisingly tolerant of corrupt lp_len fields.
1444 : : */
1445 [ - + ]: 2019064 : if (tupsize != ItemIdGetLength(itemid))
2206 andres@anarazel.de 1446 [ # # ]:UBC 0 : ereport(ERROR,
1447 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1448 : : errmsg("index tuple size does not equal lp_len in index \"%s\"",
1449 : : RelationGetRelationName(state->rel)),
1450 : : errdetail_internal("Index tid=(%u,%u) tuple size=%zu lp_len=%u page lsn=%X/%X.",
1451 : : state->targetblock, offset,
1452 : : tupsize, ItemIdGetLength(itemid),
1453 : : LSN_FORMAT_ARGS(state->targetlsn)),
1454 : : errhint("This could be a torn page problem.")));
1455 : :
1456 : : /* Check the number of index tuple attributes */
1852 pg@bowt.ie 1457 [ - + ]:CBC 2019064 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1458 : : offset))
1459 : : {
1460 : : ItemPointer tid;
1461 : : char *itid,
1462 : : *htid;
1463 : :
2199 teodor@sigaev.ru 1464 :UBC 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1509 pg@bowt.ie 1465 : 0 : tid = BTreeTupleGetPointsToTID(itup);
2199 teodor@sigaev.ru 1466 : 0 : htid = psprintf("(%u,%u)",
1467 : : ItemPointerGetBlockNumberNoCheck(tid),
1509 pg@bowt.ie 1468 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1469 : :
2199 teodor@sigaev.ru 1470 [ # # # # : 0 : ereport(ERROR,
# # ]
1471 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1472 : : errmsg("wrong number of index tuple attributes in index \"%s\"",
1473 : : RelationGetRelationName(state->rel)),
1474 : : errdetail_internal("Index tid=%s natts=%u points to %s tid=%s page lsn=%X/%X.",
1475 : : itid,
1476 : : BTreeTupleGetNAtts(itup, state->rel),
1477 : : P_ISLEAF(topaque) ? "heap" : "index",
1478 : : htid,
1479 : : LSN_FORMAT_ARGS(state->targetlsn))));
1480 : : }
1481 : :
1482 : : /*
1483 : : * Don't try to generate scankey using "negative infinity" item on
1484 : : * internal pages. They are always truncated to zero attributes.
1485 : : */
2593 andres@anarazel.de 1486 [ + + ]:CBC 2019064 : if (offset_is_negative_infinity(topaque, offset))
1487 : : {
1488 : : /*
1489 : : * We don't call bt_child_check() for "negative infinity" items.
1490 : : * But if we're performing downlink connectivity check, we do it
1491 : : * for every item including "negative infinity" one.
1492 : : */
1495 akorotkov@postgresql 1493 [ + - + + ]: 515 : if (!P_ISLEAF(topaque) && state->readonly)
1494 : : {
1495 : 12 : bt_child_highkey_check(state,
1496 : : offset,
1497 : : NULL,
1498 : : topaque->btpo_level);
1499 : : }
2593 andres@anarazel.de 1500 : 515 : continue;
1501 : : }
1502 : :
1503 : : /*
1504 : : * Readonly callers may optionally verify that non-pivot tuples can
1505 : : * each be found by an independent search that starts from the root.
1506 : : * Note that we deliberately don't do individual searches for each
1507 : : * TID, since the posting list itself is validated by other checks.
1508 : : */
1852 pg@bowt.ie 1509 [ + + + + ]: 2018549 : if (state->rootdescend && P_ISLEAF(topaque) &&
1510 [ - + ]: 201098 : !bt_rootdescend(state, itup))
1511 : : {
1509 pg@bowt.ie 1512 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1513 : : char *itid,
1514 : : *htid;
1515 : :
1852 1516 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1509 1517 : 0 : htid = psprintf("(%u,%u)", ItemPointerGetBlockNumber(tid),
1518 : 0 : ItemPointerGetOffsetNumber(tid));
1519 : :
1852 1520 [ # # ]: 0 : ereport(ERROR,
1521 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1522 : : errmsg("could not find tuple using search from root page in index \"%s\"",
1523 : : RelationGetRelationName(state->rel)),
1524 : : errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%X.",
1525 : : itid, htid,
1526 : : LSN_FORMAT_ARGS(state->targetlsn))));
1527 : : }
1528 : :
1529 : : /*
1530 : : * If tuple is a posting list tuple, make sure posting list TIDs are
1531 : : * in order
1532 : : */
1509 pg@bowt.ie 1533 [ + + ]:CBC 2018549 : if (BTreeTupleIsPosting(itup))
1534 : : {
1535 : : ItemPointerData last;
1536 : : ItemPointer current;
1537 : :
1538 : 10287 : ItemPointerCopy(BTreeTupleGetHeapTID(itup), &last);
1539 : :
1540 [ + + ]: 82219 : for (int i = 1; i < BTreeTupleGetNPosting(itup); i++)
1541 : : {
1542 : :
1543 : 71932 : current = BTreeTupleGetPostingN(itup, i);
1544 : :
1545 [ - + ]: 71932 : if (ItemPointerCompare(current, &last) <= 0)
1546 : : {
1509 pg@bowt.ie 1547 :UBC 0 : char *itid = psprintf("(%u,%u)", state->targetblock, offset);
1548 : :
1549 [ # # ]: 0 : ereport(ERROR,
1550 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1551 : : errmsg_internal("posting list contains misplaced TID in index \"%s\"",
1552 : : RelationGetRelationName(state->rel)),
1553 : : errdetail_internal("Index tid=%s posting list offset=%d page lsn=%X/%X.",
1554 : : itid, i,
1555 : : LSN_FORMAT_ARGS(state->targetlsn))));
1556 : : }
1557 : :
1509 pg@bowt.ie 1558 :CBC 71932 : ItemPointerCopy(current, &last);
1559 : : }
1560 : : }
1561 : :
1562 : : /* Build insertion scankey for current page offset */
309 1563 : 2018549 : skey = bt_mkscankey_pivotsearch(state->rel, itup);
1564 : :
1565 : : /*
1566 : : * Make sure tuple size does not exceed the relevant BTREE_VERSION
1567 : : * specific limit.
1568 : : *
1569 : : * BTREE_VERSION 4 (which introduced heapkeyspace rules) requisitioned
1570 : : * a small amount of space from BTMaxItemSize() in order to ensure
1571 : : * that suffix truncation always has enough space to add an explicit
1572 : : * heap TID back to a tuple -- we pessimistically assume that every
1573 : : * newly inserted tuple will eventually need to have a heap TID
1574 : : * appended during a future leaf page split, when the tuple becomes
1575 : : * the basis of the new high key (pivot tuple) for the leaf page.
1576 : : *
1577 : : * Since the reclaimed space is reserved for that purpose, we must not
1578 : : * enforce the slightly lower limit when the extra space has been used
1579 : : * as intended. In other words, there is only a cross-version
1580 : : * difference in the limit on tuple size within leaf pages.
1581 : : *
1582 : : * Still, we're particular about the details within BTREE_VERSION 4
1583 : : * internal pages. Pivot tuples may only use the extra space for its
1584 : : * designated purpose. Enforce the lower limit for pivot tuples when
1585 : : * an explicit heap TID isn't actually present. (In all other cases
1586 : : * suffix truncation is guaranteed to generate a pivot tuple that's no
1587 : : * larger than the firstright tuple provided to it by its caller.)
1588 : : */
1852 1589 [ + - ]: 4037098 : lowersizelimit = skey->heapkeyspace &&
1590 [ + + + + ]: 2018549 : (P_ISLEAF(topaque) || BTreeTupleGetHeapTID(itup) == NULL);
1591 [ + + - + ]: 2018565 : if (tupsize > (lowersizelimit ? BTMaxItemSize(state->target) :
1592 : 16 : BTMaxItemSizeNoHeapTid(state->target)))
1593 : : {
1509 pg@bowt.ie 1594 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1595 : : char *itid,
1596 : : *htid;
1597 : :
1852 1598 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1599 : 0 : htid = psprintf("(%u,%u)",
1600 : : ItemPointerGetBlockNumberNoCheck(tid),
1509 1601 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1602 : :
1852 1603 [ # # # # ]: 0 : ereport(ERROR,
1604 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1605 : : errmsg("index row size %zu exceeds maximum for index \"%s\"",
1606 : : tupsize, RelationGetRelationName(state->rel)),
1607 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
1608 : : itid,
1609 : : P_ISLEAF(topaque) ? "heap" : "index",
1610 : : htid,
1611 : : LSN_FORMAT_ARGS(state->targetlsn))));
1612 : : }
1613 : :
1614 : : /* Fingerprint leaf page tuples (those that point to the heap) */
2206 andres@anarazel.de 1615 [ + + + + :CBC 2018549 : if (state->heapallindexed && P_ISLEAF(topaque) && !ItemIdIsDead(itemid))
+ - ]
1616 : : {
1617 : : IndexTuple norm;
1618 : :
1509 pg@bowt.ie 1619 [ + + ]: 506946 : if (BTreeTupleIsPosting(itup))
1620 : : {
1621 : : /* Fingerprint all elements as distinct "plain" tuples */
1622 [ + + ]: 30765 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
1623 : : {
1624 : : IndexTuple logtuple;
1625 : :
1626 : 30546 : logtuple = bt_posting_plain_tuple(itup, i);
1627 : 30546 : norm = bt_normalize_tuple(state, logtuple);
1628 : 30546 : bloom_add_element(state->filter, (unsigned char *) norm,
1629 : 30546 : IndexTupleSize(norm));
1630 : : /* Be tidy */
1631 [ + + ]: 30546 : if (norm != logtuple)
1632 : 2 : pfree(norm);
1633 : 30546 : pfree(logtuple);
1634 : : }
1635 : : }
1636 : : else
1637 : : {
1638 : 506727 : norm = bt_normalize_tuple(state, itup);
1639 : 506727 : bloom_add_element(state->filter, (unsigned char *) norm,
1640 : 506727 : IndexTupleSize(norm));
1641 : : /* Be tidy */
1642 [ + + ]: 506727 : if (norm != itup)
1643 : 1 : pfree(norm);
1644 : : }
1645 : : }
1646 : :
1647 : : /*
1648 : : * * High key check *
1649 : : *
1650 : : * If there is a high key (if this is not the rightmost page on its
1651 : : * entire level), check that high key actually is upper bound on all
1652 : : * page items. If this is a posting list tuple, we'll need to set
1653 : : * scantid to be highest TID in posting list.
1654 : : *
1655 : : * We prefer to check all items against high key rather than checking
1656 : : * just the last and trusting that the operator class obeys the
1657 : : * transitive law (which implies that all previous items also
1658 : : * respected the high key invariant if they pass the item order
1659 : : * check).
1660 : : *
1661 : : * Ideally, we'd compare every item in the index against every other
1662 : : * item in the index, and not trust opclass obedience of the
1663 : : * transitive law to bridge the gap between children and their
1664 : : * grandparents (as well as great-grandparents, and so on). We don't
1665 : : * go to those lengths because that would be prohibitively expensive,
1666 : : * and probably not markedly more effective in practice.
1667 : : *
1668 : : * On the leaf level, we check that the key is <= the highkey.
1669 : : * However, on non-leaf levels we check that the key is < the highkey,
1670 : : * because the high key is "just another separator" rather than a copy
1671 : : * of some existing key item; we expect it to be unique among all keys
1672 : : * on the same level. (Suffix truncation will sometimes produce a
1673 : : * leaf highkey that is an untruncated copy of the lastleft item, but
1674 : : * never any other item, which necessitates weakening the leaf level
1675 : : * check to <=.)
1676 : : *
1677 : : * Full explanation for why a highkey is never truly a copy of another
1678 : : * item from the same level on internal levels:
1679 : : *
1680 : : * While the new left page's high key is copied from the first offset
1681 : : * on the right page during an internal page split, that's not the
1682 : : * full story. In effect, internal pages are split in the middle of
1683 : : * the firstright tuple, not between the would-be lastleft and
1684 : : * firstright tuples: the firstright key ends up on the left side as
1685 : : * left's new highkey, and the firstright downlink ends up on the
1686 : : * right side as right's new "negative infinity" item. The negative
1687 : : * infinity tuple is truncated to zero attributes, so we're only left
1688 : : * with the downlink. In other words, the copying is just an
1689 : : * implementation detail of splitting in the middle of a (pivot)
1690 : : * tuple. (See also: "Notes About Data Representation" in the nbtree
1691 : : * README.)
1692 : : */
1693 : 2018549 : scantid = skey->scantid;
1694 [ + - + + ]: 2018549 : if (state->heapkeyspace && BTreeTupleIsPosting(itup))
1695 : 10287 : skey->scantid = BTreeTupleGetMaxHeapTID(itup);
1696 : :
2593 andres@anarazel.de 1697 [ + + - + ]: 3869398 : if (!P_RIGHTMOST(topaque) &&
1852 pg@bowt.ie 1698 [ + + ]: 1850849 : !(P_ISLEAF(topaque) ? invariant_leq_offset(state, skey, P_HIKEY) :
1699 : 566 : invariant_l_offset(state, skey, P_HIKEY)))
1700 : : {
1509 pg@bowt.ie 1701 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1702 : : char *itid,
1703 : : *htid;
1704 : :
2593 andres@anarazel.de 1705 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1706 : 0 : htid = psprintf("(%u,%u)",
1707 : : ItemPointerGetBlockNumberNoCheck(tid),
1509 pg@bowt.ie 1708 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1709 : :
2593 andres@anarazel.de 1710 [ # # # # ]: 0 : ereport(ERROR,
1711 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1712 : : errmsg("high key invariant violated for index \"%s\"",
1713 : : RelationGetRelationName(state->rel)),
1714 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%X.",
1715 : : itid,
1716 : : P_ISLEAF(topaque) ? "heap" : "index",
1717 : : htid,
1718 : : LSN_FORMAT_ARGS(state->targetlsn))));
1719 : : }
1720 : : /* Reset, in case scantid was set to (itup) posting tuple's max TID */
1509 pg@bowt.ie 1721 :CBC 2018549 : skey->scantid = scantid;
1722 : :
1723 : : /*
1724 : : * * Item order check *
1725 : : *
1726 : : * Check that items are stored on page in logical order, by checking
1727 : : * current item is strictly less than next item (if any).
1728 : : */
2593 andres@anarazel.de 1729 [ + + ]: 2018549 : if (OffsetNumberNext(offset) <= max &&
1852 pg@bowt.ie 1730 [ + + ]: 2009477 : !invariant_l_offset(state, skey, OffsetNumberNext(offset)))
1731 : : {
1732 : : ItemPointer tid;
1733 : : char *itid,
1734 : : *htid,
1735 : : *nitid,
1736 : : *nhtid;
1737 : :
2593 andres@anarazel.de 1738 :GBC 3 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1509 pg@bowt.ie 1739 : 3 : tid = BTreeTupleGetPointsToTID(itup);
2593 andres@anarazel.de 1740 : 3 : htid = psprintf("(%u,%u)",
1741 : : ItemPointerGetBlockNumberNoCheck(tid),
1509 pg@bowt.ie 1742 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
2593 andres@anarazel.de 1743 : 3 : nitid = psprintf("(%u,%u)", state->targetblock,
1744 : 3 : OffsetNumberNext(offset));
1745 : :
1746 : : /* Reuse itup to get pointed-to heap location of second item */
1816 pg@bowt.ie 1747 : 3 : itemid = PageGetItemIdCareful(state, state->targetblock,
1748 : : state->target,
1749 : 3 : OffsetNumberNext(offset));
2593 andres@anarazel.de 1750 : 3 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1509 pg@bowt.ie 1751 : 3 : tid = BTreeTupleGetPointsToTID(itup);
2593 andres@anarazel.de 1752 : 3 : nhtid = psprintf("(%u,%u)",
1753 : : ItemPointerGetBlockNumberNoCheck(tid),
1509 pg@bowt.ie 1754 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
1755 : :
2593 andres@anarazel.de 1756 [ + - + + : 3 : ereport(ERROR,
+ + ]
1757 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1758 : : errmsg("item order invariant violated for index \"%s\"",
1759 : : RelationGetRelationName(state->rel)),
1760 : : errdetail_internal("Lower index tid=%s (points to %s tid=%s) "
1761 : : "higher index tid=%s (points to %s tid=%s) "
1762 : : "page lsn=%X/%X.",
1763 : : itid,
1764 : : P_ISLEAF(topaque) ? "heap" : "index",
1765 : : htid,
1766 : : nitid,
1767 : : P_ISLEAF(topaque) ? "heap" : "index",
1768 : : nhtid,
1769 : : LSN_FORMAT_ARGS(state->targetlsn))));
1770 : : }
1771 : :
1772 : : /*
1773 : : * If the index is unique verify entries uniqueness by checking the
1774 : : * heap tuples visibility.
1775 : : */
169 akorotkov@postgresql 1776 [ + + + + ]:GNC 2018546 : if (state->checkunique && state->indexinfo->ii_Unique &&
1777 [ + + + + ]: 145510 : P_ISLEAF(topaque) && !skey->anynullkeys)
1778 : 144902 : bt_entry_unique_check(state, itup, state->targetblock, offset,
1779 : : &lVis_i, &lVis_tid, &lVis_offset,
1780 : : &lVis_block);
1781 : :
1782 [ + + + + ]: 2018543 : if (state->checkunique && state->indexinfo->ii_Unique &&
1783 [ + + + + ]: 145507 : P_ISLEAF(topaque) && OffsetNumberNext(offset) <= max)
1784 : : {
1785 : : /* Save current scankey tid */
1786 : 144165 : scantid = skey->scantid;
1787 : :
1788 : : /*
1789 : : * Invalidate scankey tid to make _bt_compare compare only keys in
1790 : : * the item to report equality even if heap TIDs are different
1791 : : */
1792 : 144165 : skey->scantid = NULL;
1793 : :
1794 : : /*
1795 : : * If next key tuple is different, invalidate last visible entry
1796 : : * data (whole index tuple or last posting in index tuple). Key
1797 : : * containing null value does not violate unique constraint and
1798 : : * treated as different to any other key.
1799 : : */
1800 [ + + ]: 144165 : if (_bt_compare(state->rel, skey, state->target,
1801 [ + + ]: 144323 : OffsetNumberNext(offset)) != 0 || skey->anynullkeys)
1802 : : {
1803 : 144077 : lVis_i = -1;
1804 : 144077 : lVis_tid = NULL;
1805 : 144077 : lVis_block = InvalidBlockNumber;
1806 : 144077 : lVis_offset = InvalidOffsetNumber;
1807 : : }
1808 : 144165 : skey->scantid = scantid; /* Restore saved scan key state */
1809 : : }
1810 : :
1811 : : /*
1812 : : * * Last item check *
1813 : : *
1814 : : * Check last item against next/right page's first data item's when
1815 : : * last item on page is reached. This additional check will detect
1816 : : * transposed pages iff the supposed right sibling page happens to
1817 : : * belong before target in the key space. (Otherwise, a subsequent
1818 : : * heap verification will probably detect the problem.)
1819 : : *
1820 : : * This check is similar to the item order check that will have
1821 : : * already been performed for every other "real" item on target page
1822 : : * when last item is checked. The difference is that the next item
1823 : : * (the item that is compared to target's last item) needs to come
1824 : : * from the next/sibling page. There may not be such an item
1825 : : * available from sibling for various reasons, though (e.g., target is
1826 : : * the rightmost page on level).
1827 : : */
1828 [ + + ]: 2018543 : if (offset == max)
1829 : : {
1830 : : BTScanInsert rightkey;
1831 : : BlockNumber rightblock_number;
1832 : :
1833 : : /* first offset on a right index page (log only) */
1834 : 9072 : OffsetNumber rightfirstoffset = InvalidOffsetNumber;
1835 : :
1836 : : /* Get item in next/right page */
1837 : 9072 : rightkey = bt_right_page_check_scankey(state, &rightfirstoffset);
1838 : :
2593 andres@anarazel.de 1839 [ + + ]:CBC 9072 : if (rightkey &&
1852 pg@bowt.ie 1840 [ - + ]: 6615 : !invariant_g_offset(state, rightkey, max))
1841 : : {
1842 : : /*
1843 : : * As explained at length in bt_right_page_check_scankey(),
1844 : : * there is a known !readonly race that could account for
1845 : : * apparent violation of invariant, which we must check for
1846 : : * before actually proceeding with raising error. Our canary
1847 : : * condition is that target page was deleted.
1848 : : */
2593 andres@anarazel.de 1849 [ # # ]:UBC 0 : if (!state->readonly)
1850 : : {
1851 : : /* Get fresh copy of target page */
1852 : 0 : state->target = palloc_btree_page(state, state->targetblock);
1853 : : /* Note that we deliberately do not update target LSN */
744 michael@paquier.xyz 1854 : 0 : topaque = BTPageGetOpaque(state->target);
1855 : :
1856 : : /*
1857 : : * All !readonly checks now performed; just return
1858 : : */
2593 andres@anarazel.de 1859 [ # # ]: 0 : if (P_IGNORE(topaque))
1860 : 0 : return;
1861 : : }
1862 : :
1863 [ # # ]: 0 : ereport(ERROR,
1864 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1865 : : errmsg("cross page item order invariant violated for index \"%s\"",
1866 : : RelationGetRelationName(state->rel)),
1867 : : errdetail_internal("Last item on page tid=(%u,%u) page lsn=%X/%X.",
1868 : : state->targetblock, offset,
1869 : : LSN_FORMAT_ARGS(state->targetlsn))));
1870 : : }
1871 : :
1872 : : /*
1873 : : * If index has unique constraint make sure that no more than one
1874 : : * found equal items is visible.
1875 : : */
169 akorotkov@postgresql 1876 :GNC 9072 : rightblock_number = topaque->btpo_next;
1877 [ + + + + : 9072 : if (state->checkunique && state->indexinfo->ii_Unique &&
+ + ]
1878 [ + - + - ]: 526 : rightkey && P_ISLEAF(topaque) && rightblock_number != P_NONE)
1879 : : {
1880 [ - + ]: 526 : elog(DEBUG2, "check cross page unique condition");
1881 : :
1882 : : /*
1883 : : * Make _bt_compare compare only index keys without heap TIDs.
1884 : : * rightkey->scantid is modified destructively but it is ok
1885 : : * for it is not used later.
1886 : : */
1887 : 526 : rightkey->scantid = NULL;
1888 : :
1889 : : /* The first key on the next page is the same */
1890 [ + + - + ]: 526 : if (_bt_compare(state->rel, rightkey, state->target, max) == 0 && !rightkey->anynullkeys)
1891 : : {
169 akorotkov@postgresql 1892 [ # # ]:UNC 0 : elog(DEBUG2, "cross page equal keys");
1893 : 0 : state->target = palloc_btree_page(state,
1894 : : rightblock_number);
1895 : 0 : topaque = BTPageGetOpaque(state->target);
1896 : :
1897 [ # # # # ]: 0 : if (P_IGNORE(topaque) || !P_ISLEAF(topaque))
1898 : : break;
1899 : :
1900 : 0 : itemid = PageGetItemIdCareful(state, rightblock_number,
1901 : : state->target,
1902 : : rightfirstoffset);
1903 : 0 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1904 : :
1905 : 0 : bt_entry_unique_check(state, itup, rightblock_number, rightfirstoffset,
1906 : : &lVis_i, &lVis_tid, &lVis_offset,
1907 : : &lVis_block);
1908 : : }
1909 : : }
1910 : : }
1911 : :
1912 : : /*
1913 : : * * Downlink check *
1914 : : *
1915 : : * Additional check of child items iff this is an internal page and
1916 : : * caller holds a ShareLock. This happens for every downlink (item)
1917 : : * in target excluding the negative-infinity downlink (again, this is
1918 : : * because it has no useful value to compare).
1919 : : */
2593 andres@anarazel.de 1920 [ + + + + ]:CBC 2018543 : if (!P_ISLEAF(topaque) && state->readonly)
1495 akorotkov@postgresql 1921 : 1861 : bt_child_check(state, skey, offset);
1922 : : }
1923 : :
1924 : : /*
1925 : : * Special case bt_child_highkey_check() call
1926 : : *
1927 : : * We don't pass a real downlink, but we've to finish the level
1928 : : * processing. If condition is satisfied, we've already processed all the
1929 : : * downlinks from the target level. But there still might be pages to the
1930 : : * right of the child page pointer to by our rightmost downlink. And they
1931 : : * might have missing downlinks. This final call checks for them.
1932 : : */
1933 [ + + + + : 9074 : if (!P_ISLEAF(topaque) && P_RIGHTMOST(topaque) && state->readonly)
+ + ]
1934 : : {
1935 : 11 : bt_child_highkey_check(state, InvalidOffsetNumber,
1936 : : NULL, topaque->btpo_level);
1937 : : }
1938 : : }
1939 : :
1940 : : /*
1941 : : * Return a scankey for an item on page to right of current target (or the
1942 : : * first non-ignorable page), sufficient to check ordering invariant on last
1943 : : * item in current target page. Returned scankey relies on local memory
1944 : : * allocated for the child page, which caller cannot pfree(). Caller's memory
1945 : : * context should be reset between calls here.
1946 : : *
1947 : : * This is the first data item, and so all adjacent items are checked against
1948 : : * their immediate sibling item (which may be on a sibling page, or even a
1949 : : * "cousin" page at parent boundaries where target's rightlink points to page
1950 : : * with different parent page). If no such valid item is available, return
1951 : : * NULL instead.
1952 : : *
1953 : : * Note that !readonly callers must reverify that target page has not
1954 : : * been concurrently deleted.
1955 : : *
1956 : : * Save rightfirstdataoffset for detailed error message.
1957 : : */
1958 : : static BTScanInsert
169 akorotkov@postgresql 1959 :GNC 9072 : bt_right_page_check_scankey(BtreeCheckState *state, OffsetNumber *rightfirstoffset)
1960 : : {
1961 : : BTPageOpaque opaque;
1962 : : ItemId rightitem;
1963 : : IndexTuple firstitup;
1964 : : BlockNumber targetnext;
1965 : : Page rightpage;
1966 : : OffsetNumber nline;
1967 : :
1968 : : /* Determine target's next block number */
744 michael@paquier.xyz 1969 :CBC 9072 : opaque = BTPageGetOpaque(state->target);
1970 : :
1971 : : /* If target is already rightmost, no right sibling; nothing to do here */
2593 andres@anarazel.de 1972 [ + + ]: 9072 : if (P_RIGHTMOST(opaque))
1973 : 2457 : return NULL;
1974 : :
1975 : : /*
1976 : : * General notes on concurrent page splits and page deletion:
1977 : : *
1978 : : * Routines like _bt_search() don't require *any* page split interlock
1979 : : * when descending the tree, including something very light like a buffer
1980 : : * pin. That's why it's okay that we don't either. This avoidance of any
1981 : : * need to "couple" buffer locks is the raison d' etre of the Lehman & Yao
1982 : : * algorithm, in fact.
1983 : : *
1984 : : * That leaves deletion. A deleted page won't actually be recycled by
1985 : : * VACUUM early enough for us to fail to at least follow its right link
1986 : : * (or left link, or downlink) and find its sibling, because recycling
1987 : : * does not occur until no possible index scan could land on the page.
1988 : : * Index scans can follow links with nothing more than their snapshot as
1989 : : * an interlock and be sure of at least that much. (See page
1990 : : * recycling/"visible to everyone" notes in nbtree README.)
1991 : : *
1992 : : * Furthermore, it's okay if we follow a rightlink and find a half-dead or
1993 : : * dead (ignorable) page one or more times. There will either be a
1994 : : * further right link to follow that leads to a live page before too long
1995 : : * (before passing by parent's rightmost child), or we will find the end
1996 : : * of the entire level instead (possible when parent page is itself the
1997 : : * rightmost on its level).
1998 : : */
1999 : 6615 : targetnext = opaque->btpo_next;
2000 : : for (;;)
2001 : : {
2002 [ - + ]: 6615 : CHECK_FOR_INTERRUPTS();
2003 : :
2004 : 6615 : rightpage = palloc_btree_page(state, targetnext);
744 michael@paquier.xyz 2005 : 6615 : opaque = BTPageGetOpaque(rightpage);
2006 : :
2593 andres@anarazel.de 2007 [ - + - - ]: 6615 : if (!P_IGNORE(opaque) || P_RIGHTMOST(opaque))
2008 : : break;
2009 : :
2010 : : /*
2011 : : * We landed on a deleted or half-dead sibling page. Step right until
2012 : : * we locate a live sibling page.
2013 : : */
1125 pg@bowt.ie 2014 [ # # ]:UBC 0 : ereport(DEBUG2,
2015 : : (errcode(ERRCODE_NO_DATA),
2016 : : errmsg_internal("level %u sibling page in block %u of index \"%s\" was found deleted or half dead",
2017 : : opaque->btpo_level, targetnext, RelationGetRelationName(state->rel)),
2018 : : errdetail_internal("Deleted page found when building scankey from right sibling.")));
2019 : :
2020 : 0 : targetnext = opaque->btpo_next;
2021 : :
2022 : : /* Be slightly more pro-active in freeing this memory, just in case */
2593 andres@anarazel.de 2023 : 0 : pfree(rightpage);
2024 : : }
2025 : :
2026 : : /*
2027 : : * No ShareLock held case -- why it's safe to proceed.
2028 : : *
2029 : : * Problem:
2030 : : *
2031 : : * We must avoid false positive reports of corruption when caller treats
2032 : : * item returned here as an upper bound on target's last item. In
2033 : : * general, false positives are disallowed. Avoiding them here when
2034 : : * caller is !readonly is subtle.
2035 : : *
2036 : : * A concurrent page deletion by VACUUM of the target page can result in
2037 : : * the insertion of items on to this right sibling page that would
2038 : : * previously have been inserted on our target page. There might have
2039 : : * been insertions that followed the target's downlink after it was made
2040 : : * to point to right sibling instead of target by page deletion's first
2041 : : * phase. The inserters insert items that would belong on target page.
2042 : : * This race is very tight, but it's possible. This is our only problem.
2043 : : *
2044 : : * Non-problems:
2045 : : *
2046 : : * We are not hindered by a concurrent page split of the target; we'll
2047 : : * never land on the second half of the page anyway. A concurrent split
2048 : : * of the right page will also not matter, because the first data item
2049 : : * remains the same within the left half, which we'll reliably land on. If
2050 : : * we had to skip over ignorable/deleted pages, it cannot matter because
2051 : : * their key space has already been atomically merged with the first
2052 : : * non-ignorable page we eventually find (doesn't matter whether the page
2053 : : * we eventually find is a true sibling or a cousin of target, which we go
2054 : : * into below).
2055 : : *
2056 : : * Solution:
2057 : : *
2058 : : * Caller knows that it should reverify that target is not ignorable
2059 : : * (half-dead or deleted) when cross-page sibling item comparison appears
2060 : : * to indicate corruption (invariant fails). This detects the single race
2061 : : * condition that exists for caller. This is correct because the
2062 : : * continued existence of target block as non-ignorable (not half-dead or
2063 : : * deleted) implies that target page was not merged into from the right by
2064 : : * deletion; the key space at or after target never moved left. Target's
2065 : : * parent either has the same downlink to target as before, or a <
2066 : : * downlink due to deletion at the left of target. Target either has the
2067 : : * same highkey as before, or a highkey < before when there is a page
2068 : : * split. (The rightmost concurrently-split-from-target-page page will
2069 : : * still have the same highkey as target was originally found to have,
2070 : : * which for our purposes is equivalent to target's highkey itself never
2071 : : * changing, since we reliably skip over
2072 : : * concurrently-split-from-target-page pages.)
2073 : : *
2074 : : * In simpler terms, we allow that the key space of the target may expand
2075 : : * left (the key space can move left on the left side of target only), but
2076 : : * the target key space cannot expand right and get ahead of us without
2077 : : * our detecting it. The key space of the target cannot shrink, unless it
2078 : : * shrinks to zero due to the deletion of the original page, our canary
2079 : : * condition. (To be very precise, we're a bit stricter than that because
2080 : : * it might just have been that the target page split and only the
2081 : : * original target page was deleted. We can be more strict, just not more
2082 : : * lax.)
2083 : : *
2084 : : * Top level tree walk caller moves on to next page (makes it the new
2085 : : * target) following recovery from this race. (cf. The rationale for
2086 : : * child/downlink verification needing a ShareLock within
2087 : : * bt_child_check(), where page deletion is also the main source of
2088 : : * trouble.)
2089 : : *
2090 : : * Note that it doesn't matter if right sibling page here is actually a
2091 : : * cousin page, because in order for the key space to be readjusted in a
2092 : : * way that causes us issues in next level up (guiding problematic
2093 : : * concurrent insertions to the cousin from the grandparent rather than to
2094 : : * the sibling from the parent), there'd have to be page deletion of
2095 : : * target's parent page (affecting target's parent's downlink in target's
2096 : : * grandparent page). Internal page deletion only occurs when there are
2097 : : * no child pages (they were all fully deleted), and caller is checking
2098 : : * that the target's parent has at least one non-deleted (so
2099 : : * non-ignorable) child: the target page. (Note that the first phase of
2100 : : * deletion atomically marks the page to be deleted half-dead/ignorable at
2101 : : * the same time downlink in its parent is removed, so caller will
2102 : : * definitely not fail to detect that this happened.)
2103 : : *
2104 : : * This trick is inspired by the method backward scans use for dealing
2105 : : * with concurrent page splits; concurrent page deletion is a problem that
2106 : : * similarly receives special consideration sometimes (it's possible that
2107 : : * the backwards scan will re-read its "original" block after failing to
2108 : : * find a right-link to it, having already moved in the opposite direction
2109 : : * (right/"forwards") a few times to try to locate one). Just like us,
2110 : : * that happens only to determine if there was a concurrent page deletion
2111 : : * of a reference page, and just like us if there was a page deletion of
2112 : : * that reference page it means we can move on from caring about the
2113 : : * reference page. See the nbtree README for a full description of how
2114 : : * that works.
2115 : : */
2593 andres@anarazel.de 2116 :CBC 6615 : nline = PageGetMaxOffsetNumber(rightpage);
2117 : :
2118 : : /*
2119 : : * Get first data item, if any
2120 : : */
2121 [ + + + + : 6615 : if (P_ISLEAF(opaque) && nline >= P_FIRSTDATAKEY(opaque))
+ - ]
2122 : : {
2123 : : /* Return first data item (if any) */
1816 pg@bowt.ie 2124 : 6613 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
2125 [ + + ]: 6613 : P_FIRSTDATAKEY(opaque));
169 akorotkov@postgresql 2126 [ + + ]:GNC 6613 : *rightfirstoffset = P_FIRSTDATAKEY(opaque);
2127 : : }
2593 andres@anarazel.de 2128 [ + - + - ]:CBC 4 : else if (!P_ISLEAF(opaque) &&
2129 [ + - ]: 2 : nline >= OffsetNumberNext(P_FIRSTDATAKEY(opaque)))
2130 : : {
2131 : : /*
2132 : : * Return first item after the internal page's "negative infinity"
2133 : : * item
2134 : : */
1816 pg@bowt.ie 2135 :UBC 0 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
1816 pg@bowt.ie 2136 [ + - ]:CBC 2 : OffsetNumberNext(P_FIRSTDATAKEY(opaque)));
2137 : : }
2138 : : else
2139 : : {
2140 : : /*
2141 : : * No first item. Page is probably empty leaf page, but it's also
2142 : : * possible that it's an internal page with only a negative infinity
2143 : : * item.
2144 : : */
1125 pg@bowt.ie 2145 [ # # # # ]:UBC 0 : ereport(DEBUG2,
2146 : : (errcode(ERRCODE_NO_DATA),
2147 : : errmsg_internal("%s block %u of index \"%s\" has no first data item",
2148 : : P_ISLEAF(opaque) ? "leaf" : "internal", targetnext,
2149 : : RelationGetRelationName(state->rel))));
2593 andres@anarazel.de 2150 : 0 : return NULL;
2151 : : }
2152 : :
2153 : : /*
2154 : : * Return first real item scankey. Note that this relies on right page
2155 : : * memory remaining allocated.
2156 : : */
1852 pg@bowt.ie 2157 :CBC 6615 : firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
309 2158 : 6615 : return bt_mkscankey_pivotsearch(state->rel, firstitup);
2159 : : }
2160 : :
2161 : : /*
2162 : : * Check if two tuples are binary identical except the block number. So,
2163 : : * this function is capable to compare pivot keys on different levels.
2164 : : */
2165 : : static bool
1306 2166 : 1862 : bt_pivot_tuple_identical(bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
2167 : : {
1495 akorotkov@postgresql 2168 [ - + ]: 1862 : if (IndexTupleSize(itup1) != IndexTupleSize(itup2))
1495 akorotkov@postgresql 2169 :UBC 0 : return false;
2170 : :
1306 pg@bowt.ie 2171 [ + - ]:CBC 1862 : if (heapkeyspace)
2172 : : {
2173 : : /*
2174 : : * Offset number will contain important information in heapkeyspace
2175 : : * indexes: the number of attributes left in the pivot tuple following
2176 : : * suffix truncation. Don't skip over it (compare it too).
2177 : : */
2178 : 1862 : if (memcmp(&itup1->t_tid.ip_posid, &itup2->t_tid.ip_posid,
2179 [ - + ]: 1862 : IndexTupleSize(itup1) -
2180 : : offsetof(ItemPointerData, ip_posid)) != 0)
1306 pg@bowt.ie 2181 :UBC 0 : return false;
2182 : : }
2183 : : else
2184 : : {
2185 : : /*
2186 : : * Cannot rely on offset number field having consistent value across
2187 : : * levels on pg_upgrade'd !heapkeyspace indexes. Compare contents of
2188 : : * tuple starting from just after item pointer (i.e. after block
2189 : : * number and offset number).
2190 : : */
2191 : 0 : if (memcmp(&itup1->t_info, &itup2->t_info,
2192 [ # # ]: 0 : IndexTupleSize(itup1) -
2193 : : offsetof(IndexTupleData, t_info)) != 0)
2194 : 0 : return false;
2195 : : }
2196 : :
1495 akorotkov@postgresql 2197 :CBC 1862 : return true;
2198 : : }
2199 : :
2200 : : /*---
2201 : : * Check high keys on the child level. Traverse rightlinks from previous
2202 : : * downlink to the current one. Check that there are no intermediate pages
2203 : : * with missing downlinks.
2204 : : *
2205 : : * If 'loaded_child' is given, it's assumed to be the page pointed to by the
2206 : : * downlink referenced by 'downlinkoffnum' of the target page.
2207 : : *
2208 : : * Basically this function is called for each target downlink and checks two
2209 : : * invariants:
2210 : : *
2211 : : * 1) You can reach the next child from previous one via rightlinks;
2212 : : * 2) Each child high key have matching pivot key on target level.
2213 : : *
2214 : : * Consider the sample tree picture.
2215 : : *
2216 : : * 1
2217 : : * / \
2218 : : * 2 <-> 3
2219 : : * / \ / \
2220 : : * 4 <> 5 <> 6 <> 7 <> 8
2221 : : *
2222 : : * This function will be called for blocks 4, 5, 6 and 8. Consider what is
2223 : : * happening for each function call.
2224 : : *
2225 : : * - The function call for block 4 initializes data structure and matches high
2226 : : * key of block 4 to downlink's pivot key of block 2.
2227 : : * - The high key of block 5 is matched to the high key of block 2.
2228 : : * - The block 6 has an incomplete split flag set, so its high key isn't
2229 : : * matched to anything.
2230 : : * - The function call for block 8 checks that block 8 can be found while
2231 : : * following rightlinks from block 6. The high key of block 7 will be
2232 : : * matched to downlink's pivot key in block 3.
2233 : : *
2234 : : * There is also final call of this function, which checks that there is no
2235 : : * missing downlinks for children to the right of the child referenced by
2236 : : * rightmost downlink in target level.
2237 : : */
2238 : : static void
2239 : 1884 : bt_child_highkey_check(BtreeCheckState *state,
2240 : : OffsetNumber target_downlinkoffnum,
2241 : : Page loaded_child,
2242 : : uint32 target_level)
2243 : : {
2244 : 1884 : BlockNumber blkno = state->prevrightlink;
2245 : : Page page;
2246 : : BTPageOpaque opaque;
2247 : 1884 : bool rightsplit = state->previncompletesplit;
2248 : 1884 : bool first = true;
2249 : : ItemId itemid;
2250 : : IndexTuple itup;
2251 : : BlockNumber downlink;
2252 : :
2253 [ + + + - : 1884 : if (OffsetNumberIsValid(target_downlinkoffnum))
+ + ]
2254 : : {
2255 : 1873 : itemid = PageGetItemIdCareful(state, state->targetblock,
2256 : : state->target, target_downlinkoffnum);
2257 : 1873 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2258 : 1873 : downlink = BTreeTupleGetDownLink(itup);
2259 : : }
2260 : : else
2261 : : {
2262 : 11 : downlink = P_NONE;
2263 : : }
2264 : :
2265 : : /*
2266 : : * If no previous rightlink is memorized for current level just below
2267 : : * target page's level, we are about to start from the leftmost page. We
2268 : : * can't follow rightlinks from previous page, because there is no
2269 : : * previous page. But we still can match high key.
2270 : : *
2271 : : * So we initialize variables for the loop above like there is previous
2272 : : * page referencing current child. Also we imply previous page to not
2273 : : * have incomplete split flag, that would make us require downlink for
2274 : : * current child. That's correct, because leftmost page on the level
2275 : : * should always have parent downlink.
2276 : : */
2277 [ + + ]: 1884 : if (!BlockNumberIsValid(blkno))
2278 : : {
2279 : 11 : blkno = downlink;
2280 : 11 : rightsplit = false;
2281 : : }
2282 : :
2283 : : /* Move to the right on the child level */
2284 : : while (true)
2285 : : {
2286 : : /*
2287 : : * Did we traverse the whole tree level and this is check for pages to
2288 : : * the right of rightmost downlink?
2289 : : */
2290 [ + + + - ]: 1884 : if (blkno == P_NONE && downlink == P_NONE)
2291 : : {
2292 : 11 : state->prevrightlink = InvalidBlockNumber;
2293 : 11 : state->previncompletesplit = false;
2294 : 11 : return;
2295 : : }
2296 : :
2297 : : /* Did we traverse the whole tree level and don't find next downlink? */
2298 [ - + ]: 1873 : if (blkno == P_NONE)
1495 akorotkov@postgresql 2299 [ # # ]:UBC 0 : ereport(ERROR,
2300 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2301 : : errmsg("can't traverse from downlink %u to downlink %u of index \"%s\"",
2302 : : state->prevrightlink, downlink,
2303 : : RelationGetRelationName(state->rel))));
2304 : :
2305 : : /* Load page contents */
1495 akorotkov@postgresql 2306 [ + - + + ]:CBC 1873 : if (blkno == downlink && loaded_child)
2307 : 1861 : page = loaded_child;
2308 : : else
2309 : 12 : page = palloc_btree_page(state, blkno);
2310 : :
744 michael@paquier.xyz 2311 : 1873 : opaque = BTPageGetOpaque(page);
2312 : :
2313 : : /* The first page we visit at the level should be leftmost */
167 noah@leadboat.com 2314 [ + - + + ]: 1873 : if (first && !BlockNumberIsValid(state->prevrightlink) &&
2315 [ - + ]: 11 : !bt_leftmost_ignoring_half_dead(state, blkno, opaque))
1495 akorotkov@postgresql 2316 [ # # ]:UBC 0 : ereport(ERROR,
2317 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2318 : : errmsg("the first child of leftmost target page is not leftmost of its level in index \"%s\"",
2319 : : RelationGetRelationName(state->rel)),
2320 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2321 : : state->targetblock, blkno,
2322 : : LSN_FORMAT_ARGS(state->targetlsn))));
2323 : :
2324 : : /* Do level sanity check */
1145 pg@bowt.ie 2325 [ - + - - ]:CBC 1873 : if ((!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque)) &&
2326 [ - + ]: 1873 : opaque->btpo_level != target_level - 1)
1495 akorotkov@postgresql 2327 [ # # ]:UBC 0 : ereport(ERROR,
2328 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2329 : : errmsg("block found while following rightlinks from child of index \"%s\" has invalid level",
2330 : : RelationGetRelationName(state->rel)),
2331 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
2332 : : blkno, target_level - 1, opaque->btpo_level)));
2333 : :
2334 : : /* Try to detect circular links */
1495 akorotkov@postgresql 2335 [ - + - - :CBC 1873 : if ((!first && blkno == state->prevrightlink) || blkno == opaque->btpo_prev)
- + ]
1495 akorotkov@postgresql 2336 [ # # ]:UBC 0 : ereport(ERROR,
2337 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2338 : : errmsg("circular link chain found in block %u of index \"%s\"",
2339 : : blkno, RelationGetRelationName(state->rel))));
2340 : :
1495 akorotkov@postgresql 2341 [ - + - - ]:CBC 1873 : if (blkno != downlink && !P_IGNORE(opaque))
2342 : : {
2343 : : /* blkno probably has missing parent downlink */
1495 akorotkov@postgresql 2344 :UBC 0 : bt_downlink_missing_check(state, rightsplit, blkno, page);
2345 : : }
2346 : :
1495 akorotkov@postgresql 2347 :CBC 1873 : rightsplit = P_INCOMPLETE_SPLIT(opaque);
2348 : :
2349 : : /*
2350 : : * If we visit page with high key, check that it is equal to the
2351 : : * target key next to corresponding downlink.
2352 : : */
2353 [ + - + + ]: 1873 : if (!rightsplit && !P_RIGHTMOST(opaque))
2354 : : {
2355 : : BTPageOpaque topaque;
2356 : : IndexTuple highkey;
2357 : : OffsetNumber pivotkey_offset;
2358 : :
2359 : : /* Get high key */
2360 : 1862 : itemid = PageGetItemIdCareful(state, blkno, page, P_HIKEY);
2361 : 1862 : highkey = (IndexTuple) PageGetItem(page, itemid);
2362 : :
2363 : : /*
2364 : : * There might be two situations when we examine high key. If
2365 : : * current child page is referenced by given target downlink, we
2366 : : * should look to the next offset number for matching key from
2367 : : * target page.
2368 : : *
2369 : : * Alternatively, we're following rightlinks somewhere in the
2370 : : * middle between page referenced by previous target's downlink
2371 : : * and the page referenced by current target's downlink. If
2372 : : * current child page hasn't incomplete split flag set, then its
2373 : : * high key should match to the target's key of current offset
2374 : : * number. This happens when a previous call here (to
2375 : : * bt_child_highkey_check()) found an incomplete split, and we
2376 : : * reach a right sibling page without a downlink -- the right
2377 : : * sibling page's high key still needs to be matched to a
2378 : : * separator key on the parent/target level.
2379 : : *
2380 : : * Don't apply OffsetNumberNext() to target_downlinkoffnum when we
2381 : : * already had to step right on the child level. Our traversal of
2382 : : * the child level must try to move in perfect lockstep behind (to
2383 : : * the left of) the target/parent level traversal.
2384 : : */
2385 [ + - ]: 1862 : if (blkno == downlink)
2386 : 1862 : pivotkey_offset = OffsetNumberNext(target_downlinkoffnum);
2387 : : else
1495 akorotkov@postgresql 2388 :UBC 0 : pivotkey_offset = target_downlinkoffnum;
2389 : :
744 michael@paquier.xyz 2390 :CBC 1862 : topaque = BTPageGetOpaque(state->target);
2391 : :
1495 akorotkov@postgresql 2392 [ + - ]: 1862 : if (!offset_is_negative_infinity(topaque, pivotkey_offset))
2393 : : {
2394 : : /*
2395 : : * If we're looking for the next pivot tuple in target page,
2396 : : * but there is no more pivot tuples, then we should match to
2397 : : * high key instead.
2398 : : */
2399 [ + + ]: 1862 : if (pivotkey_offset > PageGetMaxOffsetNumber(state->target))
2400 : : {
2401 [ - + ]: 1 : if (P_RIGHTMOST(topaque))
1495 akorotkov@postgresql 2402 [ # # ]:UBC 0 : ereport(ERROR,
2403 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2404 : : errmsg("child high key is greater than rightmost pivot key on target level in index \"%s\"",
2405 : : RelationGetRelationName(state->rel)),
2406 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2407 : : state->targetblock, blkno,
2408 : : LSN_FORMAT_ARGS(state->targetlsn))));
1495 akorotkov@postgresql 2409 :CBC 1 : pivotkey_offset = P_HIKEY;
2410 : : }
2411 : 1862 : itemid = PageGetItemIdCareful(state, state->targetblock,
2412 : : state->target, pivotkey_offset);
2413 : 1862 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2414 : : }
2415 : : else
2416 : : {
2417 : : /*
2418 : : * We cannot try to match child's high key to a negative
2419 : : * infinity key in target, since there is nothing to compare.
2420 : : * However, it's still possible to match child's high key
2421 : : * outside of target page. The reason why we're are is that
2422 : : * bt_child_highkey_check() was previously called for the
2423 : : * cousin page of 'loaded_child', which is incomplete split.
2424 : : * So, now we traverse to the right of that cousin page and
2425 : : * current child level page under consideration still belongs
2426 : : * to the subtree of target's left sibling. Thus, we need to
2427 : : * match child's high key to it's left uncle page high key.
2428 : : * Thankfully we saved it, it's called a "low key" of target
2429 : : * page.
2430 : : */
1495 akorotkov@postgresql 2431 [ # # ]:UBC 0 : if (!state->lowkey)
2432 [ # # ]: 0 : ereport(ERROR,
2433 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2434 : : errmsg("can't find left sibling high key in index \"%s\"",
2435 : : RelationGetRelationName(state->rel)),
2436 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2437 : : state->targetblock, blkno,
2438 : : LSN_FORMAT_ARGS(state->targetlsn))));
2439 : 0 : itup = state->lowkey;
2440 : : }
2441 : :
1306 pg@bowt.ie 2442 [ - + ]:CBC 1862 : if (!bt_pivot_tuple_identical(state->heapkeyspace, highkey, itup))
2443 : : {
1495 akorotkov@postgresql 2444 [ # # ]:UBC 0 : ereport(ERROR,
2445 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2446 : : errmsg("mismatch between parent key and child high key in index \"%s\"",
2447 : : RelationGetRelationName(state->rel)),
2448 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%X.",
2449 : : state->targetblock, blkno,
2450 : : LSN_FORMAT_ARGS(state->targetlsn))));
2451 : : }
2452 : : }
2453 : :
2454 : : /* Exit if we already found next downlink */
1495 akorotkov@postgresql 2455 [ + - ]:CBC 1873 : if (blkno == downlink)
2456 : : {
2457 : 1873 : state->prevrightlink = opaque->btpo_next;
2458 : 1873 : state->previncompletesplit = rightsplit;
2459 : 1873 : return;
2460 : : }
2461 : :
2462 : : /* Traverse to the next page using rightlink */
1495 akorotkov@postgresql 2463 :UBC 0 : blkno = opaque->btpo_next;
2464 : :
2465 : : /* Free page contents if it's allocated by us */
2466 [ # # ]: 0 : if (page != loaded_child)
2467 : 0 : pfree(page);
2468 : 0 : first = false;
2469 : : }
2470 : : }
2471 : :
2472 : : /*
2473 : : * Checks one of target's downlink against its child page.
2474 : : *
2475 : : * Conceptually, the target page continues to be what is checked here. The
2476 : : * target block is still blamed in the event of finding an invariant violation.
2477 : : * The downlink insertion into the target is probably where any problem raised
2478 : : * here arises, and there is no such thing as a parent link, so doing the
2479 : : * verification this way around is much more practical.
2480 : : *
2481 : : * This function visits child page and it's sequentially called for each
2482 : : * downlink of target page. Assuming this we also check downlink connectivity
2483 : : * here in order to save child page visits.
2484 : : */
2485 : : static void
1495 akorotkov@postgresql 2486 :CBC 1861 : bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
2487 : : OffsetNumber downlinkoffnum)
2488 : : {
2489 : : ItemId itemid;
2490 : : IndexTuple itup;
2491 : : BlockNumber childblock;
2492 : : OffsetNumber offset;
2493 : : OffsetNumber maxoffset;
2494 : : Page child;
2495 : : BTPageOpaque copaque;
2496 : : BTPageOpaque topaque;
2497 : :
2498 : 1861 : itemid = PageGetItemIdCareful(state, state->targetblock,
2499 : : state->target, downlinkoffnum);
2500 : 1861 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2501 : 1861 : childblock = BTreeTupleGetDownLink(itup);
2502 : :
2503 : : /*
2504 : : * Caller must have ShareLock on target relation, because of
2505 : : * considerations around page deletion by VACUUM.
2506 : : *
2507 : : * NB: In general, page deletion deletes the right sibling's downlink, not
2508 : : * the downlink of the page being deleted; the deleted page's downlink is
2509 : : * reused for its sibling. The key space is thereby consolidated between
2510 : : * the deleted page and its right sibling. (We cannot delete a parent
2511 : : * page's rightmost child unless it is the last child page, and we intend
2512 : : * to also delete the parent itself.)
2513 : : *
2514 : : * If this verification happened without a ShareLock, the following race
2515 : : * condition could cause false positives:
2516 : : *
2517 : : * In general, concurrent page deletion might occur, including deletion of
2518 : : * the left sibling of the child page that is examined here. If such a
2519 : : * page deletion were to occur, closely followed by an insertion into the
2520 : : * newly expanded key space of the child, a window for the false positive
2521 : : * opens up: the stale parent/target downlink originally followed to get
2522 : : * to the child legitimately ceases to be a lower bound on all items in
2523 : : * the page, since the key space was concurrently expanded "left".
2524 : : * (Insertion followed the "new" downlink for the child, not our now-stale
2525 : : * downlink, which was concurrently physically removed in target/parent as
2526 : : * part of deletion's first phase.)
2527 : : *
2528 : : * While we use various techniques elsewhere to perform cross-page
2529 : : * verification for !readonly callers, a similar trick seems difficult
2530 : : * here. The tricks used by bt_recheck_sibling_links and by
2531 : : * bt_right_page_check_scankey both involve verification of a same-level,
2532 : : * cross-sibling invariant. Cross-level invariants are far more squishy,
2533 : : * though. The nbtree REDO routines do not actually couple buffer locks
2534 : : * across levels during page splits, so making any cross-level check work
2535 : : * reliably in !readonly mode may be impossible.
2536 : : */
2593 andres@anarazel.de 2537 [ - + ]: 1861 : Assert(state->readonly);
2538 : :
2539 : : /*
2540 : : * Verify child page has the downlink key from target page (its parent) as
2541 : : * a lower bound; downlink must be strictly less than all keys on the
2542 : : * page.
2543 : : *
2544 : : * Check all items, rather than checking just the first and trusting that
2545 : : * the operator class obeys the transitive law.
2546 : : */
744 michael@paquier.xyz 2547 : 1861 : topaque = BTPageGetOpaque(state->target);
2593 andres@anarazel.de 2548 : 1861 : child = palloc_btree_page(state, childblock);
744 michael@paquier.xyz 2549 : 1861 : copaque = BTPageGetOpaque(child);
2593 andres@anarazel.de 2550 : 1861 : maxoffset = PageGetMaxOffsetNumber(child);
2551 : :
2552 : : /*
2553 : : * Since we've already loaded the child block, combine this check with
2554 : : * check for downlink connectivity.
2555 : : */
1495 akorotkov@postgresql 2556 : 1861 : bt_child_highkey_check(state, downlinkoffnum,
2557 : : child, topaque->btpo_level);
2558 : :
2559 : : /*
2560 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2561 : : * and since a page has no links within other pages (siblings and parent)
2562 : : * once it is marked fully deleted, it should be impossible to land on a
2563 : : * fully deleted page.
2564 : : *
2565 : : * It does not quite make sense to enforce that the page cannot even be
2566 : : * half-dead, despite the fact the downlink is modified at the same stage
2567 : : * that the child leaf page is marked half-dead. That's incorrect because
2568 : : * there may occasionally be multiple downlinks from a chain of pages
2569 : : * undergoing deletion, where multiple successive calls are made to
2570 : : * _bt_unlink_halfdead_page() by VACUUM before it can finally safely mark
2571 : : * the leaf page as fully dead. While _bt_mark_page_halfdead() usually
2572 : : * removes the downlink to the leaf page that is marked half-dead, that's
2573 : : * not guaranteed, so it's possible we'll land on a half-dead page with a
2574 : : * downlink due to an interrupted multi-level page deletion.
2575 : : *
2576 : : * We go ahead with our checks if the child page is half-dead. It's safe
2577 : : * to do so because we do not test the child's high key, so it does not
2578 : : * matter that the original high key will have been replaced by a dummy
2579 : : * truncated high key within _bt_mark_page_halfdead(). All other page
2580 : : * items are left intact on a half-dead page, so there is still something
2581 : : * to test.
2582 : : */
2181 teodor@sigaev.ru 2583 [ - + ]: 1861 : if (P_ISDELETED(copaque))
2181 teodor@sigaev.ru 2584 [ # # ]:UBC 0 : ereport(ERROR,
2585 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2586 : : errmsg("downlink to deleted page found in index \"%s\"",
2587 : : RelationGetRelationName(state->rel)),
2588 : : errdetail_internal("Parent block=%u child block=%u parent page lsn=%X/%X.",
2589 : : state->targetblock, childblock,
2590 : : LSN_FORMAT_ARGS(state->targetlsn))));
2591 : :
2593 andres@anarazel.de 2592 [ + + ]:CBC 1861 : for (offset = P_FIRSTDATAKEY(copaque);
2593 [ + + ]: 600350 : offset <= maxoffset;
2594 : 598489 : offset = OffsetNumberNext(offset))
2595 : : {
2596 : : /*
2597 : : * Skip comparison of target page key against "negative infinity"
2598 : : * item, if any. Checking it would indicate that it's not a strict
2599 : : * lower bound, but that's only because of the hard-coding for
2600 : : * negative infinity items within _bt_compare().
2601 : : *
2602 : : * If nbtree didn't truncate negative infinity tuples during internal
2603 : : * page splits then we'd expect child's negative infinity key to be
2604 : : * equal to the scankey/downlink from target/parent (it would be a
2605 : : * "low key" in this hypothetical scenario, and so it would still need
2606 : : * to be treated as a special case here).
2607 : : *
2608 : : * Negative infinity items can be thought of as a strict lower bound
2609 : : * that works transitively, with the last non-negative-infinity pivot
2610 : : * followed during a descent from the root as its "true" strict lower
2611 : : * bound. Only a small number of negative infinity items are truly
2612 : : * negative infinity; those that are the first items of leftmost
2613 : : * internal pages. In more general terms, a negative infinity item is
2614 : : * only negative infinity with respect to the subtree that the page is
2615 : : * at the root of.
2616 : : *
2617 : : * See also: bt_rootdescend(), which can even detect transitive
2618 : : * inconsistencies on cousin leaf pages.
2619 : : */
2620 [ + + ]: 598489 : if (offset_is_negative_infinity(copaque, offset))
2621 : 1 : continue;
2622 : :
1816 pg@bowt.ie 2623 [ - + ]: 598488 : if (!invariant_l_nontarget_offset(state, targetkey, childblock, child,
2624 : : offset))
2593 andres@anarazel.de 2625 [ # # ]:UBC 0 : ereport(ERROR,
2626 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2627 : : errmsg("down-link lower bound invariant violated for index \"%s\"",
2628 : : RelationGetRelationName(state->rel)),
2629 : : errdetail_internal("Parent block=%u child index tid=(%u,%u) parent page lsn=%X/%X.",
2630 : : state->targetblock, childblock, offset,
2631 : : LSN_FORMAT_ARGS(state->targetlsn))));
2632 : : }
2633 : :
2593 andres@anarazel.de 2634 :CBC 1861 : pfree(child);
2635 : 1861 : }
2636 : :
2637 : : /*
2638 : : * Checks if page is missing a downlink that it should have.
2639 : : *
2640 : : * A page that lacks a downlink/parent may indicate corruption. However, we
2641 : : * must account for the fact that a missing downlink can occasionally be
2642 : : * encountered in a non-corrupt index. This can be due to an interrupted page
2643 : : * split, or an interrupted multi-level page deletion (i.e. there was a hard
2644 : : * crash or an error during a page split, or while VACUUM was deleting a
2645 : : * multi-level chain of pages).
2646 : : *
2647 : : * Note that this can only be called in readonly mode, so there is no need to
2648 : : * be concerned about concurrent page splits or page deletions.
2649 : : */
2650 : : static void
1495 akorotkov@postgresql 2651 :UBC 0 : bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
2652 : : BlockNumber blkno, Page page)
2653 : : {
744 michael@paquier.xyz 2654 : 0 : BTPageOpaque opaque = BTPageGetOpaque(page);
2655 : : ItemId itemid;
2656 : : IndexTuple itup;
2657 : : Page child;
2658 : : BTPageOpaque copaque;
2659 : : uint32 level;
2660 : : BlockNumber childblk;
2661 : : XLogRecPtr pagelsn;
2662 : :
1495 akorotkov@postgresql 2663 [ # # ]: 0 : Assert(state->readonly);
2664 [ # # ]: 0 : Assert(!P_IGNORE(opaque));
2665 : :
2666 : : /* No next level up with downlinks to fingerprint from the true root */
2667 [ # # ]: 0 : if (P_ISROOT(opaque))
2181 teodor@sigaev.ru 2668 : 0 : return;
2669 : :
1495 akorotkov@postgresql 2670 : 0 : pagelsn = PageGetLSN(page);
2671 : :
2672 : : /*
2673 : : * Incomplete (interrupted) page splits can account for the lack of a
2674 : : * downlink. Some inserting transaction should eventually complete the
2675 : : * page split in passing, when it notices that the left sibling page is
2676 : : * P_INCOMPLETE_SPLIT().
2677 : : *
2678 : : * In general, VACUUM is not prepared for there to be no downlink to a
2679 : : * page that it deletes. This is the main reason why the lack of a
2680 : : * downlink can be reported as corruption here. It's not obvious that an
2681 : : * invalid missing downlink can result in wrong answers to queries,
2682 : : * though, since index scans that land on the child may end up
2683 : : * consistently moving right. The handling of concurrent page splits (and
2684 : : * page deletions) within _bt_moveright() cannot distinguish
2685 : : * inconsistencies that last for a moment from inconsistencies that are
2686 : : * permanent and irrecoverable.
2687 : : *
2688 : : * VACUUM isn't even prepared to delete pages that have no downlink due to
2689 : : * an incomplete page split, but it can detect and reason about that case
2690 : : * by design, so it shouldn't be taken to indicate corruption. See
2691 : : * _bt_pagedel() for full details.
2692 : : */
2693 [ # # ]: 0 : if (rightsplit)
2694 : : {
2181 teodor@sigaev.ru 2695 [ # # ]: 0 : ereport(DEBUG1,
2696 : : (errcode(ERRCODE_NO_DATA),
2697 : : errmsg_internal("harmless interrupted page split detected in index \"%s\"",
2698 : : RelationGetRelationName(state->rel)),
2699 : : errdetail_internal("Block=%u level=%u left sibling=%u page lsn=%X/%X.",
2700 : : blkno, opaque->btpo_level,
2701 : : opaque->btpo_prev,
2702 : : LSN_FORMAT_ARGS(pagelsn))));
2703 : 0 : return;
2704 : : }
2705 : :
2706 : : /*
2707 : : * Page under check is probably the "top parent" of a multi-level page
2708 : : * deletion. We'll need to descend the subtree to make sure that
2709 : : * descendant pages are consistent with that, though.
2710 : : *
2711 : : * If the page (which must be non-ignorable) is a leaf page, then clearly
2712 : : * it can't be the top parent. The lack of a downlink is probably a
2713 : : * symptom of a broad problem that could just as easily cause
2714 : : * inconsistencies anywhere else.
2715 : : */
1495 akorotkov@postgresql 2716 [ # # ]: 0 : if (P_ISLEAF(opaque))
2181 teodor@sigaev.ru 2717 [ # # ]: 0 : ereport(ERROR,
2718 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2719 : : errmsg("leaf index block lacks downlink in index \"%s\"",
2720 : : RelationGetRelationName(state->rel)),
2721 : : errdetail_internal("Block=%u page lsn=%X/%X.",
2722 : : blkno,
2723 : : LSN_FORMAT_ARGS(pagelsn))));
2724 : :
2725 : : /* Descend from the given page, which is an internal page */
2726 [ # # ]: 0 : elog(DEBUG1, "checking for interrupted multi-level deletion due to missing downlink in index \"%s\"",
2727 : : RelationGetRelationName(state->rel));
2728 : :
1145 pg@bowt.ie 2729 : 0 : level = opaque->btpo_level;
1495 akorotkov@postgresql 2730 [ # # ]: 0 : itemid = PageGetItemIdCareful(state, blkno, page, P_FIRSTDATAKEY(opaque));
2731 : 0 : itup = (IndexTuple) PageGetItem(page, itemid);
1581 pg@bowt.ie 2732 : 0 : childblk = BTreeTupleGetDownLink(itup);
2733 : : for (;;)
2734 : : {
2181 teodor@sigaev.ru 2735 [ # # ]: 0 : CHECK_FOR_INTERRUPTS();
2736 : :
2737 : 0 : child = palloc_btree_page(state, childblk);
744 michael@paquier.xyz 2738 : 0 : copaque = BTPageGetOpaque(child);
2739 : :
2181 teodor@sigaev.ru 2740 [ # # ]: 0 : if (P_ISLEAF(copaque))
2741 : 0 : break;
2742 : :
2743 : : /* Do an extra sanity check in passing on internal pages */
1145 pg@bowt.ie 2744 [ # # ]: 0 : if (copaque->btpo_level != level - 1)
2181 teodor@sigaev.ru 2745 [ # # ]: 0 : ereport(ERROR,
2746 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2747 : : errmsg_internal("downlink points to block in index \"%s\" whose level is not one level down",
2748 : : RelationGetRelationName(state->rel)),
2749 : : errdetail_internal("Top parent/under check block=%u block pointed to=%u expected level=%u level in pointed to block=%u.",
2750 : : blkno, childblk,
2751 : : level - 1, copaque->btpo_level)));
2752 : :
1145 pg@bowt.ie 2753 : 0 : level = copaque->btpo_level;
1816 2754 : 0 : itemid = PageGetItemIdCareful(state, childblk, child,
2755 [ # # ]: 0 : P_FIRSTDATAKEY(copaque));
2181 teodor@sigaev.ru 2756 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
1581 pg@bowt.ie 2757 : 0 : childblk = BTreeTupleGetDownLink(itup);
2758 : : /* Be slightly more pro-active in freeing this memory, just in case */
2181 teodor@sigaev.ru 2759 : 0 : pfree(child);
2760 : : }
2761 : :
2762 : : /*
2763 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2764 : : * and since a page has no links within other pages (siblings and parent)
2765 : : * once it is marked fully deleted, it should be impossible to land on a
2766 : : * fully deleted page. See bt_child_check() for further details.
2767 : : *
2768 : : * The bt_child_check() P_ISDELETED() check is repeated here because
2769 : : * bt_child_check() does not visit pages reachable through negative
2770 : : * infinity items. Besides, bt_child_check() is unwilling to descend
2771 : : * multiple levels. (The similar bt_child_check() P_ISDELETED() check
2772 : : * within bt_check_level_from_leftmost() won't reach the page either,
2773 : : * since the leaf's live siblings should have their sibling links updated
2774 : : * to bypass the deletion target page when it is marked fully dead.)
2775 : : *
2776 : : * If this error is raised, it might be due to a previous multi-level page
2777 : : * deletion that failed to realize that it wasn't yet safe to mark the
2778 : : * leaf page as fully dead. A "dangling downlink" will still remain when
2779 : : * this happens. The fact that the dangling downlink's page (the leaf's
2780 : : * parent/ancestor page) lacked a downlink is incidental.
2781 : : */
2782 [ # # ]: 0 : if (P_ISDELETED(copaque))
2783 [ # # ]: 0 : ereport(ERROR,
2784 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2785 : : errmsg_internal("downlink to deleted leaf page found in index \"%s\"",
2786 : : RelationGetRelationName(state->rel)),
2787 : : errdetail_internal("Top parent/target block=%u leaf block=%u top parent/under check lsn=%X/%X.",
2788 : : blkno, childblk,
2789 : : LSN_FORMAT_ARGS(pagelsn))));
2790 : :
2791 : : /*
2792 : : * Iff leaf page is half-dead, its high key top parent link should point
2793 : : * to what VACUUM considered to be the top parent page at the instant it
2794 : : * was interrupted. Provided the high key link actually points to the
2795 : : * page under check, the missing downlink we detected is consistent with
2796 : : * there having been an interrupted multi-level page deletion. This means
2797 : : * that the subtree with the page under check at its root (a page deletion
2798 : : * chain) is in a consistent state, enabling VACUUM to resume deleting the
2799 : : * entire chain the next time it encounters the half-dead leaf page.
2800 : : */
2801 [ # # # # ]: 0 : if (P_ISHALFDEAD(copaque) && !P_RIGHTMOST(copaque))
2802 : : {
1816 pg@bowt.ie 2803 : 0 : itemid = PageGetItemIdCareful(state, childblk, child, P_HIKEY);
2181 teodor@sigaev.ru 2804 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
1495 akorotkov@postgresql 2805 [ # # ]: 0 : if (BTreeTupleGetTopParent(itup) == blkno)
2181 teodor@sigaev.ru 2806 : 0 : return;
2807 : : }
2808 : :
2809 [ # # ]: 0 : ereport(ERROR,
2810 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2811 : : errmsg("internal index block lacks downlink in index \"%s\"",
2812 : : RelationGetRelationName(state->rel)),
2813 : : errdetail_internal("Block=%u level=%u page lsn=%X/%X.",
2814 : : blkno, opaque->btpo_level,
2815 : : LSN_FORMAT_ARGS(pagelsn))));
2816 : : }
2817 : :
2818 : : /*
2819 : : * Per-tuple callback from table_index_build_scan, used to determine if index has
2820 : : * all the entries that definitely should have been observed in leaf pages of
2821 : : * the target index (that is, all IndexTuples that were fingerprinted by our
2822 : : * Bloom filter). All heapallindexed checks occur here.
2823 : : *
2824 : : * The redundancy between an index and the table it indexes provides a good
2825 : : * opportunity to detect corruption, especially corruption within the table.
2826 : : * The high level principle behind the verification performed here is that any
2827 : : * IndexTuple that should be in an index following a fresh CREATE INDEX (based
2828 : : * on the same index definition) should also have been in the original,
2829 : : * existing index, which should have used exactly the same representation
2830 : : *
2831 : : * Since the overall structure of the index has already been verified, the most
2832 : : * likely explanation for error here is a corrupt heap page (could be logical
2833 : : * or physical corruption). Index corruption may still be detected here,
2834 : : * though. Only readonly callers will have verified that left links and right
2835 : : * links are in agreement, and so it's possible that a leaf page transposition
2836 : : * within index is actually the source of corruption detected here (for
2837 : : * !readonly callers). The checks performed only for readonly callers might
2838 : : * more accurately frame the problem as a cross-page invariant issue (this
2839 : : * could even be due to recovery not replaying all WAL records). The !readonly
2840 : : * ERROR message raised here includes a HINT about retrying with readonly
2841 : : * verification, just in case it's a cross-page invariant issue, though that
2842 : : * isn't particularly likely.
2843 : : *
2844 : : * table_index_build_scan() expects to be able to find the root tuple when a
2845 : : * heap-only tuple (the live tuple at the end of some HOT chain) needs to be
2846 : : * indexed, in order to replace the actual tuple's TID with the root tuple's
2847 : : * TID (which is what we're actually passed back here). The index build heap
2848 : : * scan code will raise an error when a tuple that claims to be the root of the
2849 : : * heap-only tuple's HOT chain cannot be located. This catches cases where the
2850 : : * original root item offset/root tuple for a HOT chain indicates (for whatever
2851 : : * reason) that the entire HOT chain is dead, despite the fact that the latest
2852 : : * heap-only tuple should be indexed. When this happens, sequential scans may
2853 : : * always give correct answers, and all indexes may be considered structurally
2854 : : * consistent (i.e. the nbtree structural checks would not detect corruption).
2855 : : * It may be the case that only index scans give wrong answers, and yet heap or
2856 : : * SLRU corruption is the real culprit. (While it's true that LP_DEAD bit
2857 : : * setting will probably also leave the index in a corrupt state before too
2858 : : * long, the problem is nonetheless that there is heap corruption.)
2859 : : *
2860 : : * Heap-only tuple handling within table_index_build_scan() works in a way that
2861 : : * helps us to detect index tuples that contain the wrong values (values that
2862 : : * don't match the latest tuple in the HOT chain). This can happen when there
2863 : : * is no superseding index tuple due to a faulty assessment of HOT safety,
2864 : : * perhaps during the original CREATE INDEX. Because the latest tuple's
2865 : : * contents are used with the root TID, an error will be raised when a tuple
2866 : : * with the same TID but non-matching attribute values is passed back to us.
2867 : : * Faulty assessment of HOT-safety was behind at least two distinct CREATE
2868 : : * INDEX CONCURRENTLY bugs that made it into stable releases, one of which was
2869 : : * undetected for many years. In short, the same principle that allows a
2870 : : * REINDEX to repair corruption when there was an (undetected) broken HOT chain
2871 : : * also allows us to detect the corruption in many cases.
2872 : : */
2873 : : static void
1619 andres@anarazel.de 2874 :CBC 534868 : bt_tuple_present_callback(Relation index, ItemPointer tid, Datum *values,
2875 : : bool *isnull, bool tupleIsAlive, void *checkstate)
2876 : : {
2206 2877 : 534868 : BtreeCheckState *state = (BtreeCheckState *) checkstate;
2878 : : IndexTuple itup,
2879 : : norm;
2880 : :
2881 [ - + ]: 534868 : Assert(state->heapallindexed);
2882 : :
2883 : : /* Generate a normalized index tuple for fingerprinting */
2884 : 534868 : itup = index_form_tuple(RelationGetDescr(index), values, isnull);
1619 2885 : 534868 : itup->t_tid = *tid;
1894 pg@bowt.ie 2886 : 534868 : norm = bt_normalize_tuple(state, itup);
2887 : :
2888 : : /* Probe Bloom filter -- tuple should be present */
2889 [ - + ]: 534868 : if (bloom_lacks_element(state->filter, (unsigned char *) norm,
2890 : 534868 : IndexTupleSize(norm)))
2206 andres@anarazel.de 2891 [ # # # # ]:UBC 0 : ereport(ERROR,
2892 : : (errcode(ERRCODE_DATA_CORRUPTED),
2893 : : errmsg("heap tuple (%u,%u) from table \"%s\" lacks matching index tuple within index \"%s\"",
2894 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2895 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2896 : : RelationGetRelationName(state->heaprel),
2897 : : RelationGetRelationName(state->rel)),
2898 : : !state->readonly
2899 : : ? errhint("Retrying verification using the function bt_index_parent_check() might provide a more specific error.")
2900 : : : 0));
2901 : :
2206 andres@anarazel.de 2902 :CBC 534868 : state->heaptuplespresent++;
2903 : 534868 : pfree(itup);
2904 : : /* Cannot leak memory here */
1894 pg@bowt.ie 2905 [ + + ]: 534868 : if (norm != itup)
2906 : 5 : pfree(norm);
2907 : 534868 : }
2908 : :
2909 : : /*
2910 : : * Normalize an index tuple for fingerprinting.
2911 : : *
2912 : : * In general, index tuple formation is assumed to be deterministic by
2913 : : * heapallindexed verification, and IndexTuples are assumed immutable. While
2914 : : * the LP_DEAD bit is mutable in leaf pages, that's ItemId metadata, which is
2915 : : * not fingerprinted. Normalization is required to compensate for corner
2916 : : * cases where the determinism assumption doesn't quite work.
2917 : : *
2918 : : * There is currently one such case: index_form_tuple() does not try to hide
2919 : : * the source TOAST state of input datums. The executor applies TOAST
2920 : : * compression for heap tuples based on different criteria to the compression
2921 : : * applied within btinsert()'s call to index_form_tuple(): it sometimes
2922 : : * compresses more aggressively, resulting in compressed heap tuple datums but
2923 : : * uncompressed corresponding index tuple datums. A subsequent heapallindexed
2924 : : * verification will get a logically equivalent though bitwise unequal tuple
2925 : : * from index_form_tuple(). False positive heapallindexed corruption reports
2926 : : * could occur without normalizing away the inconsistency.
2927 : : *
2928 : : * Returned tuple is often caller's own original tuple. Otherwise, it is a
2929 : : * new representation of caller's original index tuple, palloc()'d in caller's
2930 : : * memory context.
2931 : : *
2932 : : * Note: This routine is not concerned with distinctions about the
2933 : : * representation of tuples beyond those that might break heapallindexed
2934 : : * verification. In particular, it won't try to normalize opclass-equal
2935 : : * datums with potentially distinct representations (e.g., btree/numeric_ops
2936 : : * index datums will not get their display scale normalized-away here).
2937 : : * Caller does normalization for non-pivot tuples that have a posting list,
2938 : : * since dummy CREATE INDEX callback code generates new tuples with the same
2939 : : * normalized representation.
2940 : : */
2941 : : static IndexTuple
2942 : 1072141 : bt_normalize_tuple(BtreeCheckState *state, IndexTuple itup)
2943 : : {
2944 : 1072141 : TupleDesc tupleDescriptor = RelationGetDescr(state->rel);
2945 : : Datum normalized[INDEX_MAX_KEYS];
2946 : : bool isnull[INDEX_MAX_KEYS];
2947 : : bool need_free[INDEX_MAX_KEYS];
2948 : 1072141 : bool formnewtup = false;
2949 : : IndexTuple reformed;
2950 : : int i;
2951 : :
2952 : : /* Caller should only pass "logical" non-pivot tuples here */
1509 2953 [ + - - + ]: 1072141 : Assert(!BTreeTupleIsPosting(itup) && !BTreeTupleIsPivot(itup));
2954 : :
2955 : : /* Easy case: It's immediately clear that tuple has no varlena datums */
1894 2956 [ + + ]: 1072141 : if (!IndexTupleHasVarwidths(itup))
2957 : 1072117 : return itup;
2958 : :
2959 [ + + ]: 48 : for (i = 0; i < tupleDescriptor->natts; i++)
2960 : : {
2961 : : Form_pg_attribute att;
2962 : :
2963 : 24 : att = TupleDescAttr(tupleDescriptor, i);
2964 : :
2965 : : /* Assume untoasted/already normalized datum initially */
22 akorotkov@postgresql 2966 : 24 : need_free[i] = false;
1894 pg@bowt.ie 2967 : 24 : normalized[i] = index_getattr(itup, att->attnum,
2968 : : tupleDescriptor,
2969 : : &isnull[i]);
2970 [ + - + - : 24 : if (att->attbyval || att->attlen != -1 || isnull[i])
- + ]
1894 pg@bowt.ie 2971 :UBC 0 : continue;
2972 : :
2973 : : /*
2974 : : * Callers always pass a tuple that could safely be inserted into the
2975 : : * index without further processing, so an external varlena header
2976 : : * should never be encountered here
2977 : : */
1894 pg@bowt.ie 2978 [ - + ]:CBC 24 : if (VARATT_IS_EXTERNAL(DatumGetPointer(normalized[i])))
1894 pg@bowt.ie 2979 [ # # ]:UBC 0 : ereport(ERROR,
2980 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2981 : : errmsg("external varlena datum in tuple that references heap row (%u,%u) in index \"%s\"",
2982 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2983 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2984 : : RelationGetRelationName(state->rel))));
22 akorotkov@postgresql 2985 [ + + ]:CBC 24 : else if (!VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])) &&
2986 [ + + ]: 22 : VARSIZE(DatumGetPointer(normalized[i])) > TOAST_INDEX_TARGET &&
2987 [ + + ]: 21 : (att->attstorage == TYPSTORAGE_EXTENDED ||
2988 [ - + ]: 16 : att->attstorage == TYPSTORAGE_MAIN))
2989 : : {
2990 : : /*
2991 : : * This value will be compressed by index_form_tuple() with the
2992 : : * current storage settings. We may be here because this tuple
2993 : : * was formed with different storage settings. So, force forming.
2994 : : */
2995 : 5 : formnewtup = true;
2996 : : }
1894 pg@bowt.ie 2997 [ + + ]: 19 : else if (VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])))
2998 : : {
2999 : 2 : formnewtup = true;
3000 : 2 : normalized[i] = PointerGetDatum(PG_DETOAST_DATUM(normalized[i]));
22 akorotkov@postgresql 3001 : 2 : need_free[i] = true;
3002 : : }
3003 : :
3004 : : /*
3005 : : * Short tuples may have 1B or 4B header. Convert 4B header of short
3006 : : * tuples to 1B
3007 : : */
3008 [ + + + + ]: 17 : else if (VARATT_CAN_MAKE_SHORT(DatumGetPointer(normalized[i])))
3009 : : {
3010 : : /* convert to short varlena */
3011 : 1 : Size len = VARATT_CONVERTED_SHORT_SIZE(DatumGetPointer(normalized[i]));
3012 : 1 : char *data = palloc(len);
3013 : :
3014 : 1 : SET_VARSIZE_SHORT(data, len);
3015 : 1 : memcpy(data + 1, VARDATA(DatumGetPointer(normalized[i])), len - 1);
3016 : :
3017 : 1 : formnewtup = true;
3018 : 1 : normalized[i] = PointerGetDatum(data);
3019 : 1 : need_free[i] = true;
3020 : : }
3021 : : }
3022 : :
3023 : : /*
3024 : : * Easier case: Tuple has varlena datums, none of which are compressed or
3025 : : * short with 4B header
3026 : : */
1894 pg@bowt.ie 3027 [ + + ]: 24 : if (!formnewtup)
3028 : 16 : return itup;
3029 : :
3030 : : /*
3031 : : * Hard case: Tuple had compressed varlena datums that necessitate
3032 : : * creating normalized version of the tuple from uncompressed input datums
3033 : : * (normalized input datums). This is rather naive, but shouldn't be
3034 : : * necessary too often.
3035 : : *
3036 : : * In the heap, tuples may contain short varlena datums with both 1B
3037 : : * header and 4B headers. But the corresponding index tuple should always
3038 : : * have such varlena's with 1B headers. So, if there is a short varlena
3039 : : * with 4B header, we need to convert it for for fingerprinting.
3040 : : *
3041 : : * Note that we rely on deterministic index_form_tuple() TOAST compression
3042 : : * of normalized input.
3043 : : */
3044 : 8 : reformed = index_form_tuple(tupleDescriptor, normalized, isnull);
3045 : 8 : reformed->t_tid = itup->t_tid;
3046 : :
3047 : : /* Cannot leak memory here */
3048 [ + + ]: 16 : for (i = 0; i < tupleDescriptor->natts; i++)
22 akorotkov@postgresql 3049 [ + + ]: 8 : if (need_free[i])
1894 pg@bowt.ie 3050 : 3 : pfree(DatumGetPointer(normalized[i]));
3051 : :
3052 : 8 : return reformed;
3053 : : }
3054 : :
3055 : : /*
3056 : : * Produce palloc()'d "plain" tuple for nth posting list entry/TID.
3057 : : *
3058 : : * In general, deduplication is not supposed to change the logical contents of
3059 : : * an index. Multiple index tuples are merged together into one equivalent
3060 : : * posting list index tuple when convenient.
3061 : : *
3062 : : * heapallindexed verification must normalize-away this variation in
3063 : : * representation by converting posting list tuples into two or more "plain"
3064 : : * tuples. Each tuple must be fingerprinted separately -- there must be one
3065 : : * tuple for each corresponding Bloom filter probe during the heap scan.
3066 : : *
3067 : : * Note: Caller still needs to call bt_normalize_tuple() with returned tuple.
3068 : : */
3069 : : static inline IndexTuple
1509 3070 : 30546 : bt_posting_plain_tuple(IndexTuple itup, int n)
3071 : : {
3072 [ - + ]: 30546 : Assert(BTreeTupleIsPosting(itup));
3073 : :
3074 : : /* Returns non-posting-list tuple */
3075 : 30546 : return _bt_form_posting(itup, BTreeTupleGetPostingN(itup, n), 1);
3076 : : }
3077 : :
3078 : : /*
3079 : : * Search for itup in index, starting from fast root page. itup must be a
3080 : : * non-pivot tuple. This is only supported with heapkeyspace indexes, since
3081 : : * we rely on having fully unique keys to find a match with only a single
3082 : : * visit to a leaf page, barring an interrupted page split, where we may have
3083 : : * to move right. (A concurrent page split is impossible because caller must
3084 : : * be readonly caller.)
3085 : : *
3086 : : * This routine can detect very subtle transitive consistency issues across
3087 : : * more than one level of the tree. Leaf pages all have a high key (even the
3088 : : * rightmost page has a conceptual positive infinity high key), but not a low
3089 : : * key. Their downlink in parent is a lower bound, which along with the high
3090 : : * key is almost enough to detect every possible inconsistency. A downlink
3091 : : * separator key value won't always be available from parent, though, because
3092 : : * the first items of internal pages are negative infinity items, truncated
3093 : : * down to zero attributes during internal page splits. While it's true that
3094 : : * bt_child_check() and the high key check can detect most imaginable key
3095 : : * space problems, there are remaining problems it won't detect with non-pivot
3096 : : * tuples in cousin leaf pages. Starting a search from the root for every
3097 : : * existing leaf tuple detects small inconsistencies in upper levels of the
3098 : : * tree that cannot be detected any other way. (Besides all this, this is
3099 : : * probably also useful as a direct test of the code used by index scans
3100 : : * themselves.)
3101 : : */
3102 : : static bool
1852 3103 : 201098 : bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
3104 : : {
3105 : : BTScanInsert key;
3106 : : BTStack stack;
3107 : : Buffer lbuf;
3108 : : bool exists;
3109 : :
309 3110 : 201098 : key = _bt_mkscankey(state->rel, itup);
1852 3111 [ + - - + ]: 201098 : Assert(key->heapkeyspace && key->scantid != NULL);
3112 : :
3113 : : /*
3114 : : * Search from root.
3115 : : *
3116 : : * Ideally, we would arrange to only move right within _bt_search() when
3117 : : * an interrupted page split is detected (i.e. when the incomplete split
3118 : : * bit is found to be set), but for now we accept the possibility that
3119 : : * that could conceal an inconsistency.
3120 : : */
3121 [ + - - + ]: 201098 : Assert(state->readonly && state->rootdescend);
3122 : 201098 : exists = false;
219 tmunro@postgresql.or 3123 :GNC 201098 : stack = _bt_search(state->rel, NULL, key, &lbuf, BT_READ);
3124 : :
1852 pg@bowt.ie 3125 [ + - ]:CBC 201098 : if (BufferIsValid(lbuf))
3126 : : {
3127 : : BTInsertStateData insertstate;
3128 : : OffsetNumber offnum;
3129 : : Page page;
3130 : :
3131 : 201098 : insertstate.itup = itup;
3132 : 201098 : insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
3133 : 201098 : insertstate.itup_key = key;
1509 3134 : 201098 : insertstate.postingoff = 0;
1852 3135 : 201098 : insertstate.bounds_valid = false;
3136 : 201098 : insertstate.buf = lbuf;
3137 : :
3138 : : /* Get matching tuple on leaf page */
3139 : 201098 : offnum = _bt_binsrch_insert(state->rel, &insertstate);
3140 : : /* Compare first >= matching item on leaf page, if any */
3141 : 201098 : page = BufferGetPage(lbuf);
3142 : : /* Should match on first heap TID when tuple has a posting list */
3143 [ + - ]: 201098 : if (offnum <= PageGetMaxOffsetNumber(page) &&
1509 3144 [ + - + - ]: 402196 : insertstate.postingoff <= 0 &&
1852 3145 : 201098 : _bt_compare(state->rel, key, page, offnum) == 0)
3146 : 201098 : exists = true;
3147 : 201098 : _bt_relbuf(state->rel, lbuf);
3148 : : }
3149 : :
3150 : 201098 : _bt_freestack(stack);
3151 : 201098 : pfree(key);
3152 : :
3153 : 201098 : return exists;
3154 : : }
3155 : :
3156 : : /*
3157 : : * Is particular offset within page (whose special state is passed by caller)
3158 : : * the page negative-infinity item?
3159 : : *
3160 : : * As noted in comments above _bt_compare(), there is special handling of the
3161 : : * first data item as a "negative infinity" item. The hard-coding within
3162 : : * _bt_compare() makes comparing this item for the purposes of verification
3163 : : * pointless at best, since the IndexTuple only contains a valid TID (a
3164 : : * reference TID to child page).
3165 : : */
3166 : : static inline bool
2593 andres@anarazel.de 3167 : 2619415 : offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
3168 : : {
3169 : : /*
3170 : : * For internal pages only, the first item after high key, if any, is
3171 : : * negative infinity item. Internal pages always have a negative infinity
3172 : : * item, whereas leaf pages never have one. This implies that negative
3173 : : * infinity item is either first or second line item, or there is none
3174 : : * within page.
3175 : : *
3176 : : * Negative infinity items are a special case among pivot tuples. They
3177 : : * always have zero attributes, while all other pivot tuples always have
3178 : : * nkeyatts attributes.
3179 : : *
3180 : : * Right-most pages don't have a high key, but could be said to
3181 : : * conceptually have a "positive infinity" high key. Thus, there is a
3182 : : * symmetry between down link items in parent pages, and high keys in
3183 : : * children. Together, they represent the part of the key space that
3184 : : * belongs to each page in the index. For example, all children of the
3185 : : * root page will have negative infinity as a lower bound from root
3186 : : * negative infinity downlink, and positive infinity as an upper bound
3187 : : * (implicitly, from "imaginary" positive infinity high key in root).
3188 : : */
3189 [ + + + + : 2619415 : return !P_ISLEAF(opaque) && offset == P_FIRSTDATAKEY(opaque);
+ + ]
3190 : : }
3191 : :
3192 : : /*
3193 : : * Does the invariant hold that the key is strictly less than a given upper
3194 : : * bound offset item?
3195 : : *
3196 : : * Verifies line pointer on behalf of caller.
3197 : : *
3198 : : * If this function returns false, convention is that caller throws error due
3199 : : * to corruption.
3200 : : */
3201 : : static inline bool
1852 pg@bowt.ie 3202 : 2010043 : invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
3203 : : OffsetNumber upperbound)
3204 : : {
3205 : : ItemId itemid;
3206 : : int32 cmp;
3207 : :
128 pg@bowt.ie 3208 [ + - - + ]:GNC 2010043 : Assert(!key->nextkey && key->backward);
3209 : :
3210 : : /* Verify line pointer before checking tuple */
1816 pg@bowt.ie 3211 :CBC 2010043 : itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
3212 : : upperbound);
3213 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
1852 3214 [ - + ]: 2010043 : if (!key->heapkeyspace)
1852 pg@bowt.ie 3215 :UBC 0 : return invariant_leq_offset(state, key, upperbound);
3216 : :
1852 pg@bowt.ie 3217 :CBC 2010043 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3218 : :
3219 : : /*
3220 : : * _bt_compare() is capable of determining that a scankey with a
3221 : : * filled-out attribute is greater than pivot tuples where the comparison
3222 : : * is resolved at a truncated attribute (value of attribute in pivot is
3223 : : * minus infinity). However, it is not capable of determining that a
3224 : : * scankey is _less than_ a tuple on the basis of a comparison resolved at
3225 : : * _scankey_ minus infinity attribute. Complete an extra step to simulate
3226 : : * having minus infinity values for omitted scankey attribute(s).
3227 : : */
3228 [ - + ]: 2010043 : if (cmp == 0)
3229 : : {
3230 : : BTPageOpaque topaque;
3231 : : IndexTuple ritup;
3232 : : int uppnkeyatts;
3233 : : ItemPointer rheaptid;
3234 : : bool nonpivot;
3235 : :
1852 pg@bowt.ie 3236 :UBC 0 : ritup = (IndexTuple) PageGetItem(state->target, itemid);
744 michael@paquier.xyz 3237 : 0 : topaque = BTPageGetOpaque(state->target);
1852 pg@bowt.ie 3238 [ # # # # : 0 : nonpivot = P_ISLEAF(topaque) && upperbound >= P_FIRSTDATAKEY(topaque);
# # ]
3239 : :
3240 : : /* Get number of keys + heap TID for item to the right */
3241 [ # # # # : 0 : uppnkeyatts = BTreeTupleGetNKeyAtts(ritup, state->rel);
# # ]
3242 : 0 : rheaptid = BTreeTupleGetHeapTIDCareful(state, ritup, nonpivot);
3243 : :
3244 : : /* Heap TID is tiebreaker key attribute */
3245 [ # # ]: 0 : if (key->keysz == uppnkeyatts)
3246 [ # # # # ]: 0 : return key->scantid == NULL && rheaptid != NULL;
3247 : :
3248 : 0 : return key->keysz < uppnkeyatts;
3249 : : }
3250 : :
1852 pg@bowt.ie 3251 :CBC 2010043 : return cmp < 0;
3252 : : }
3253 : :
3254 : : /*
3255 : : * Does the invariant hold that the key is less than or equal to a given upper
3256 : : * bound offset item?
3257 : : *
3258 : : * Caller should have verified that upperbound's line pointer is consistent
3259 : : * using PageGetItemIdCareful() call.
3260 : : *
3261 : : * If this function returns false, convention is that caller throws error due
3262 : : * to corruption.
3263 : : */
3264 : : static inline bool
3265 : 1850283 : invariant_leq_offset(BtreeCheckState *state, BTScanInsert key,
3266 : : OffsetNumber upperbound)
3267 : : {
3268 : : int32 cmp;
3269 : :
128 pg@bowt.ie 3270 [ + - - + ]:GNC 1850283 : Assert(!key->nextkey && key->backward);
3271 : :
1852 pg@bowt.ie 3272 :CBC 1850283 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3273 : :
2593 andres@anarazel.de 3274 : 1850283 : return cmp <= 0;
3275 : : }
3276 : :
3277 : : /*
3278 : : * Does the invariant hold that the key is strictly greater than a given lower
3279 : : * bound offset item?
3280 : : *
3281 : : * Caller should have verified that lowerbound's line pointer is consistent
3282 : : * using PageGetItemIdCareful() call.
3283 : : *
3284 : : * If this function returns false, convention is that caller throws error due
3285 : : * to corruption.
3286 : : */
3287 : : static inline bool
1852 pg@bowt.ie 3288 : 6615 : invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
3289 : : OffsetNumber lowerbound)
3290 : : {
3291 : : int32 cmp;
3292 : :
128 pg@bowt.ie 3293 [ + - - + ]:GNC 6615 : Assert(!key->nextkey && key->backward);
3294 : :
1852 pg@bowt.ie 3295 :CBC 6615 : cmp = _bt_compare(state->rel, key, state->target, lowerbound);
3296 : :
3297 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3298 [ - + ]: 6615 : if (!key->heapkeyspace)
1852 pg@bowt.ie 3299 :UBC 0 : return cmp >= 0;
3300 : :
3301 : : /*
3302 : : * No need to consider the possibility that scankey has attributes that we
3303 : : * need to force to be interpreted as negative infinity. _bt_compare() is
3304 : : * able to determine that scankey is greater than negative infinity. The
3305 : : * distinction between "==" and "<" isn't interesting here, since
3306 : : * corruption is indicated either way.
3307 : : */
1852 pg@bowt.ie 3308 :CBC 6615 : return cmp > 0;
3309 : : }
3310 : :
3311 : : /*
3312 : : * Does the invariant hold that the key is strictly less than a given upper
3313 : : * bound offset item, with the offset relating to a caller-supplied page that
3314 : : * is not the current target page?
3315 : : *
3316 : : * Caller's non-target page is a child page of the target, checked as part of
3317 : : * checking a property of the target page (i.e. the key comes from the
3318 : : * target). Verifies line pointer on behalf of caller.
3319 : : *
3320 : : * If this function returns false, convention is that caller throws error due
3321 : : * to corruption.
3322 : : */
3323 : : static inline bool
3324 : 598488 : invariant_l_nontarget_offset(BtreeCheckState *state, BTScanInsert key,
3325 : : BlockNumber nontargetblock, Page nontarget,
3326 : : OffsetNumber upperbound)
3327 : : {
3328 : : ItemId itemid;
3329 : : int32 cmp;
3330 : :
128 pg@bowt.ie 3331 [ + - - + ]:GNC 598488 : Assert(!key->nextkey && key->backward);
3332 : :
3333 : : /* Verify line pointer before checking tuple */
1816 pg@bowt.ie 3334 :CBC 598488 : itemid = PageGetItemIdCareful(state, nontargetblock, nontarget,
3335 : : upperbound);
1852 3336 : 598488 : cmp = _bt_compare(state->rel, key, nontarget, upperbound);
3337 : :
3338 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3339 [ - + ]: 598488 : if (!key->heapkeyspace)
1852 pg@bowt.ie 3340 :UBC 0 : return cmp <= 0;
3341 : :
3342 : : /* See invariant_l_offset() for an explanation of this extra step */
1852 pg@bowt.ie 3343 [ + + ]:CBC 598488 : if (cmp == 0)
3344 : : {
3345 : : IndexTuple child;
3346 : : int uppnkeyatts;
3347 : : ItemPointer childheaptid;
3348 : : BTPageOpaque copaque;
3349 : : bool nonpivot;
3350 : :
3351 : 1860 : child = (IndexTuple) PageGetItem(nontarget, itemid);
744 michael@paquier.xyz 3352 : 1860 : copaque = BTPageGetOpaque(nontarget);
1852 pg@bowt.ie 3353 [ + - + + : 1860 : nonpivot = P_ISLEAF(copaque) && upperbound >= P_FIRSTDATAKEY(copaque);
+ - ]
3354 : :
3355 : : /* Get number of keys + heap TID for child/non-target item */
3356 [ - + + + : 1860 : uppnkeyatts = BTreeTupleGetNKeyAtts(child, state->rel);
- + ]
3357 : 1860 : childheaptid = BTreeTupleGetHeapTIDCareful(state, child, nonpivot);
3358 : :
3359 : : /* Heap TID is tiebreaker key attribute */
3360 [ + - ]: 1860 : if (key->keysz == uppnkeyatts)
3361 [ + - + - ]: 1860 : return key->scantid == NULL && childheaptid != NULL;
3362 : :
1852 pg@bowt.ie 3363 :UBC 0 : return key->keysz < uppnkeyatts;
3364 : : }
3365 : :
1852 pg@bowt.ie 3366 :CBC 596628 : return cmp < 0;
3367 : : }
3368 : :
3369 : : /*
3370 : : * Given a block number of a B-Tree page, return page in palloc()'d memory.
3371 : : * While at it, perform some basic checks of the page.
3372 : : *
3373 : : * There is never an attempt to get a consistent view of multiple pages using
3374 : : * multiple concurrent buffer locks; in general, we only acquire a single pin
3375 : : * and buffer lock at a time, which is often all that the nbtree code requires.
3376 : : * (Actually, bt_recheck_sibling_links couples buffer locks, which is the only
3377 : : * exception to this general rule.)
3378 : : *
3379 : : * Operating on a copy of the page is useful because it prevents control
3380 : : * getting stuck in an uninterruptible state when an underlying operator class
3381 : : * misbehaves.
3382 : : */
3383 : : static Page
2593 andres@anarazel.de 3384 : 21587 : palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
3385 : : {
3386 : : Buffer buffer;
3387 : : Page page;
3388 : : BTPageOpaque opaque;
3389 : : OffsetNumber maxoffset;
3390 : :
3391 : 21587 : page = palloc(BLCKSZ);
3392 : :
3393 : : /*
3394 : : * We copy the page into local storage to avoid holding pin on the buffer
3395 : : * longer than we must.
3396 : : */
3397 : 21587 : buffer = ReadBufferExtended(state->rel, MAIN_FORKNUM, blocknum, RBM_NORMAL,
3398 : : state->checkstrategy);
3399 : 21575 : LockBuffer(buffer, BT_READ);
3400 : :
3401 : : /*
3402 : : * Perform the same basic sanity checking that nbtree itself performs for
3403 : : * every page:
3404 : : */
3405 : 21575 : _bt_checkpage(state->rel, buffer);
3406 : :
3407 : : /* Only use copy of page in palloc()'d memory */
3408 : 21575 : memcpy(page, BufferGetPage(buffer), BLCKSZ);
3409 : 21575 : UnlockReleaseBuffer(buffer);
3410 : :
744 michael@paquier.xyz 3411 : 21575 : opaque = BTPageGetOpaque(page);
3412 : :
2400 tgl@sss.pgh.pa.us 3413 [ + + - + ]: 21575 : if (P_ISMETA(opaque) && blocknum != BTREE_METAPAGE)
2593 andres@anarazel.de 3414 [ # # ]:UBC 0 : ereport(ERROR,
3415 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3416 : : errmsg("invalid meta page found at block %u in index \"%s\"",
3417 : : blocknum, RelationGetRelationName(state->rel))));
3418 : :
3419 : : /* Check page from block that ought to be meta page */
2593 andres@anarazel.de 3420 [ + + ]:CBC 21575 : if (blocknum == BTREE_METAPAGE)
3421 : : {
3422 : 4005 : BTMetaPageData *metad = BTPageGetMeta(page);
3423 : :
2400 tgl@sss.pgh.pa.us 3424 [ + - ]: 4005 : if (!P_ISMETA(opaque) ||
2593 andres@anarazel.de 3425 [ - + ]: 4005 : metad->btm_magic != BTREE_MAGIC)
2593 andres@anarazel.de 3426 [ # # ]:UBC 0 : ereport(ERROR,
3427 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3428 : : errmsg("index \"%s\" meta page is corrupt",
3429 : : RelationGetRelationName(state->rel))));
3430 : :
2202 teodor@sigaev.ru 3431 [ + - ]:CBC 4005 : if (metad->btm_version < BTREE_MIN_VERSION ||
3432 [ - + ]: 4005 : metad->btm_version > BTREE_VERSION)
2593 andres@anarazel.de 3433 [ # # ]:UBC 0 : ereport(ERROR,
3434 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3435 : : errmsg("version mismatch in index \"%s\": file version %d, "
3436 : : "current version %d, minimum supported version %d",
3437 : : RelationGetRelationName(state->rel),
3438 : : metad->btm_version, BTREE_VERSION,
3439 : : BTREE_MIN_VERSION)));
3440 : :
3441 : : /* Finished with metapage checks */
2181 teodor@sigaev.ru 3442 :CBC 4005 : return page;
3443 : : }
3444 : :
3445 : : /*
3446 : : * Deleted pages that still use the old 32-bit XID representation have no
3447 : : * sane "level" field because they type pun the field, but all other pages
3448 : : * (including pages deleted on Postgres 14+) have a valid value.
3449 : : */
1145 pg@bowt.ie 3450 [ - + - - ]: 17570 : if (!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque))
3451 : : {
3452 : : /* Okay, no reason not to trust btpo_level field from page */
3453 : :
3454 [ + + - + ]: 17570 : if (P_ISLEAF(opaque) && opaque->btpo_level != 0)
1145 pg@bowt.ie 3455 [ # # ]:UBC 0 : ereport(ERROR,
3456 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3457 : : errmsg_internal("invalid leaf page level %u for block %u in index \"%s\"",
3458 : : opaque->btpo_level, blocknum,
3459 : : RelationGetRelationName(state->rel))));
3460 : :
1145 pg@bowt.ie 3461 [ + + - + ]:CBC 17570 : if (!P_ISLEAF(opaque) && opaque->btpo_level == 0)
1145 pg@bowt.ie 3462 [ # # ]:UBC 0 : ereport(ERROR,
3463 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3464 : : errmsg_internal("invalid internal page level 0 for block %u in index \"%s\"",
3465 : : blocknum,
3466 : : RelationGetRelationName(state->rel))));
3467 : : }
3468 : :
3469 : : /*
3470 : : * Sanity checks for number of items on page.
3471 : : *
3472 : : * As noted at the beginning of _bt_binsrch(), an internal page must have
3473 : : * children, since there must always be a negative infinity downlink
3474 : : * (there may also be a highkey). In the case of non-rightmost leaf
3475 : : * pages, there must be at least a highkey. The exceptions are deleted
3476 : : * pages, which contain no items.
3477 : : *
3478 : : * This is correct when pages are half-dead, since internal pages are
3479 : : * never half-dead, and leaf pages must have a high key when half-dead
3480 : : * (the rightmost page can never be deleted). It's also correct with
3481 : : * fully deleted pages: _bt_unlink_halfdead_page() doesn't change anything
3482 : : * about the target page other than setting the page as fully dead, and
3483 : : * setting its xact field. In particular, it doesn't change the sibling
3484 : : * links in the deletion target itself, since they're required when index
3485 : : * scans land on the deletion target, and then need to move right (or need
3486 : : * to move left, in the case of backward index scans).
3487 : : */
2181 teodor@sigaev.ru 3488 :CBC 17570 : maxoffset = PageGetMaxOffsetNumber(page);
3489 [ - + ]: 17570 : if (maxoffset > MaxIndexTuplesPerPage)
2181 teodor@sigaev.ru 3490 [ # # ]:UBC 0 : ereport(ERROR,
3491 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3492 : : errmsg("Number of items on block %u of index \"%s\" exceeds MaxIndexTuplesPerPage (%u)",
3493 : : blocknum, RelationGetRelationName(state->rel),
3494 : : MaxIndexTuplesPerPage)));
3495 : :
1431 akorotkov@postgresql 3496 [ + + + - :CBC 17570 : if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) && maxoffset < P_FIRSTDATAKEY(opaque))
+ + - + ]
2181 teodor@sigaev.ru 3497 [ # # ]:UBC 0 : ereport(ERROR,
3498 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3499 : : errmsg("internal block %u in index \"%s\" lacks high key and/or at least one downlink",
3500 : : blocknum, RelationGetRelationName(state->rel))));
3501 : :
1431 akorotkov@postgresql 3502 [ + + + - :CBC 17570 : if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && !P_RIGHTMOST(opaque) && maxoffset < P_HIKEY)
+ + - + ]
2181 teodor@sigaev.ru 3503 [ # # ]:UBC 0 : ereport(ERROR,
3504 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3505 : : errmsg("non-rightmost leaf block %u in index \"%s\" lacks high key item",
3506 : : blocknum, RelationGetRelationName(state->rel))));
3507 : :
3508 : : /*
3509 : : * In general, internal pages are never marked half-dead, except on
3510 : : * versions of Postgres prior to 9.4, where it can be valid transient
3511 : : * state. This state is nonetheless treated as corruption by VACUUM on
3512 : : * from version 9.4 on, so do the same here. See _bt_pagedel() for full
3513 : : * details.
3514 : : */
2181 teodor@sigaev.ru 3515 [ + + - + ]:CBC 17570 : if (!P_ISLEAF(opaque) && P_ISHALFDEAD(opaque))
2181 teodor@sigaev.ru 3516 [ # # ]:UBC 0 : ereport(ERROR,
3517 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3518 : : errmsg("internal page block %u in index \"%s\" is half-dead",
3519 : : blocknum, RelationGetRelationName(state->rel)),
3520 : : errhint("This can be caused by an interrupted VACUUM in version 9.3 or older, before upgrade. Please REINDEX it.")));
3521 : :
3522 : : /*
3523 : : * Check that internal pages have no garbage items, and that no page has
3524 : : * an invalid combination of deletion-related page level flags
3525 : : */
2593 andres@anarazel.de 3526 [ + + - + ]:CBC 17570 : if (!P_ISLEAF(opaque) && P_HAS_GARBAGE(opaque))
2593 andres@anarazel.de 3527 [ # # ]:UBC 0 : ereport(ERROR,
3528 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3529 : : errmsg_internal("internal page block %u in index \"%s\" has garbage items",
3530 : : blocknum, RelationGetRelationName(state->rel))));
3531 : :
1145 pg@bowt.ie 3532 [ - + - - ]:CBC 17570 : if (P_HAS_FULLXID(opaque) && !P_ISDELETED(opaque))
1145 pg@bowt.ie 3533 [ # # ]:UBC 0 : ereport(ERROR,
3534 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3535 : : errmsg_internal("full transaction id page flag appears in non-deleted block %u in index \"%s\"",
3536 : : blocknum, RelationGetRelationName(state->rel))));
3537 : :
1145 pg@bowt.ie 3538 [ - + - - ]:CBC 17570 : if (P_ISDELETED(opaque) && P_ISHALFDEAD(opaque))
1145 pg@bowt.ie 3539 [ # # ]:UBC 0 : ereport(ERROR,
3540 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3541 : : errmsg_internal("deleted page block %u in index \"%s\" is half-dead",
3542 : : blocknum, RelationGetRelationName(state->rel))));
3543 : :
2593 andres@anarazel.de 3544 :CBC 17570 : return page;
3545 : : }
3546 : :
3547 : : /*
3548 : : * _bt_mkscankey() wrapper that automatically prevents insertion scankey from
3549 : : * being considered greater than the pivot tuple that its values originated
3550 : : * from (or some other identical pivot tuple) in the common case where there
3551 : : * are truncated/minus infinity attributes. Without this extra step, there
3552 : : * are forms of corruption that amcheck could theoretically fail to report.
3553 : : *
3554 : : * For example, invariant_g_offset() might miss a cross-page invariant failure
3555 : : * on an internal level if the scankey built from the first item on the
3556 : : * target's right sibling page happened to be equal to (not greater than) the
3557 : : * last item on target page. The !backward tiebreaker in _bt_compare() might
3558 : : * otherwise cause amcheck to assume (rather than actually verify) that the
3559 : : * scankey is greater.
3560 : : */
3561 : : static inline BTScanInsert
309 pg@bowt.ie 3562 : 2025164 : bt_mkscankey_pivotsearch(Relation rel, IndexTuple itup)
3563 : : {
3564 : : BTScanInsert skey;
3565 : :
3566 : 2025164 : skey = _bt_mkscankey(rel, itup);
128 pg@bowt.ie 3567 :GNC 2025164 : skey->backward = true;
3568 : :
1852 pg@bowt.ie 3569 :CBC 2025164 : return skey;
3570 : : }
3571 : :
3572 : : /*
3573 : : * PageGetItemId() wrapper that validates returned line pointer.
3574 : : *
3575 : : * Buffer page/page item access macros generally trust that line pointers are
3576 : : * not corrupt, which might cause problems for verification itself. For
3577 : : * example, there is no bounds checking in PageGetItem(). Passing it a
3578 : : * corrupt line pointer can cause it to return a tuple/pointer that is unsafe
3579 : : * to dereference.
3580 : : *
3581 : : * Validating line pointers before tuples avoids undefined behavior and
3582 : : * assertion failures with corrupt indexes, making the verification process
3583 : : * more robust and predictable.
3584 : : */
3585 : : static ItemId
1816 3586 : 4650665 : PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page,
3587 : : OffsetNumber offset)
3588 : : {
3589 : 4650665 : ItemId itemid = PageGetItemId(page, offset);
3590 : :
3591 [ - + ]: 4650665 : if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
3592 : : BLCKSZ - MAXALIGN(sizeof(BTPageOpaqueData)))
1816 pg@bowt.ie 3593 [ # # ]:UBC 0 : ereport(ERROR,
3594 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3595 : : errmsg("line pointer points past end of tuple space in index \"%s\"",
3596 : : RelationGetRelationName(state->rel)),
3597 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3598 : : block, offset, ItemIdGetOffset(itemid),
3599 : : ItemIdGetLength(itemid),
3600 : : ItemIdGetFlags(itemid))));
3601 : :
3602 : : /*
3603 : : * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree
3604 : : * never uses either. Verify that line pointer has storage, too, since
3605 : : * even LP_DEAD items should within nbtree.
3606 : : */
1816 pg@bowt.ie 3607 [ + - + - ]:CBC 4650665 : if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
3608 [ - + ]: 4650665 : ItemIdGetLength(itemid) == 0)
1816 pg@bowt.ie 3609 [ # # ]:UBC 0 : ereport(ERROR,
3610 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3611 : : errmsg("invalid line pointer storage in index \"%s\"",
3612 : : RelationGetRelationName(state->rel)),
3613 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3614 : : block, offset, ItemIdGetOffset(itemid),
3615 : : ItemIdGetLength(itemid),
3616 : : ItemIdGetFlags(itemid))));
3617 : :
1816 pg@bowt.ie 3618 :CBC 4650665 : return itemid;
3619 : : }
3620 : :
3621 : : /*
3622 : : * BTreeTupleGetHeapTID() wrapper that enforces that a heap TID is present in
3623 : : * cases where that is mandatory (i.e. for non-pivot tuples)
3624 : : */
3625 : : static inline ItemPointer
1852 3626 : 1860 : BTreeTupleGetHeapTIDCareful(BtreeCheckState *state, IndexTuple itup,
3627 : : bool nonpivot)
3628 : : {
3629 : : ItemPointer htid;
3630 : :
3631 : : /*
3632 : : * Caller determines whether this is supposed to be a pivot or non-pivot
3633 : : * tuple using page type and item offset number. Verify that tuple
3634 : : * metadata agrees with this.
3635 : : */
1509 3636 [ - + ]: 1860 : Assert(state->heapkeyspace);
3637 [ - + - - ]: 1860 : if (BTreeTupleIsPivot(itup) && nonpivot)
1509 pg@bowt.ie 3638 [ # # ]:UBC 0 : ereport(ERROR,
3639 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3640 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected pivot tuple",
3641 : : state->targetblock,
3642 : : RelationGetRelationName(state->rel))));
3643 : :
1509 pg@bowt.ie 3644 [ + - - + ]:CBC 1860 : if (!BTreeTupleIsPivot(itup) && !nonpivot)
1509 pg@bowt.ie 3645 [ # # ]:UBC 0 : ereport(ERROR,
3646 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3647 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected non-pivot tuple",
3648 : : state->targetblock,
3649 : : RelationGetRelationName(state->rel))));
3650 : :
1509 pg@bowt.ie 3651 :CBC 1860 : htid = BTreeTupleGetHeapTID(itup);
3652 [ - + - - ]: 1860 : if (!ItemPointerIsValid(htid) && nonpivot)
1852 pg@bowt.ie 3653 [ # # ]:UBC 0 : ereport(ERROR,
3654 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3655 : : errmsg("block %u or its right sibling block or child block in index \"%s\" contains non-pivot tuple that lacks a heap TID",
3656 : : state->targetblock,
3657 : : RelationGetRelationName(state->rel))));
3658 : :
1509 pg@bowt.ie 3659 :CBC 1860 : return htid;
3660 : : }
3661 : :
3662 : : /*
3663 : : * Return the "pointed to" TID for itup, which is used to generate a
3664 : : * descriptive error message. itup must be a "data item" tuple (it wouldn't
3665 : : * make much sense to call here with a high key tuple, since there won't be a
3666 : : * valid downlink/block number to display).
3667 : : *
3668 : : * Returns either a heap TID (which will be the first heap TID in posting list
3669 : : * if itup is posting list tuple), or a TID that contains downlink block
3670 : : * number, plus some encoded metadata (e.g., the number of attributes present
3671 : : * in itup).
3672 : : */
3673 : : static inline ItemPointer
1509 pg@bowt.ie 3674 :GBC 6 : BTreeTupleGetPointsToTID(IndexTuple itup)
3675 : : {
3676 : : /*
3677 : : * Rely on the assumption that !heapkeyspace internal page data items will
3678 : : * correctly return TID with downlink here -- BTreeTupleGetHeapTID() won't
3679 : : * recognize it as a pivot tuple, but everything still works out because
3680 : : * the t_tid field is still returned
3681 : : */
3682 [ + + ]: 6 : if (!BTreeTupleIsPivot(itup))
3683 : 4 : return BTreeTupleGetHeapTID(itup);
3684 : :
3685 : : /* Pivot tuple returns TID with downlink block (heapkeyspace variant) */
3686 : 2 : return &itup->t_tid;
3687 : : }
|
