Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * xlogutils.c
4 : : *
5 : : * PostgreSQL write-ahead log manager utility routines
6 : : *
7 : : * This file contains support routines that are used by XLOG replay functions.
8 : : * None of this code is used during normal system operation.
9 : : *
10 : : *
11 : : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
12 : : * Portions Copyright (c) 1994, Regents of the University of California
13 : : *
14 : : * src/backend/access/transam/xlogutils.c
15 : : *
16 : : *-------------------------------------------------------------------------
17 : : */
18 : : #include "postgres.h"
19 : :
20 : : #include <unistd.h>
21 : :
22 : : #include "access/timeline.h"
23 : : #include "access/xlogrecovery.h"
24 : : #include "access/xlog_internal.h"
25 : : #include "access/xlogutils.h"
26 : : #include "miscadmin.h"
27 : : #include "storage/fd.h"
28 : : #include "storage/smgr.h"
29 : : #include "utils/hsearch.h"
30 : : #include "utils/rel.h"
31 : :
32 : :
33 : : /* GUC variable */
34 : : bool ignore_invalid_pages = false;
35 : :
36 : : /*
37 : : * Are we doing recovery from XLOG?
38 : : *
39 : : * This is only ever true in the startup process; it should be read as meaning
40 : : * "this process is replaying WAL records", rather than "the system is in
41 : : * recovery mode". It should be examined primarily by functions that need
42 : : * to act differently when called from a WAL redo function (e.g., to skip WAL
43 : : * logging). To check whether the system is in recovery regardless of which
44 : : * process you're running in, use RecoveryInProgress() but only after shared
45 : : * memory startup and lock initialization.
46 : : *
47 : : * This is updated from xlog.c and xlogrecovery.c, but lives here because
48 : : * it's mostly read by WAL redo functions.
49 : : */
50 : : bool InRecovery = false;
51 : :
52 : : /* Are we in Hot Standby mode? Only valid in startup process, see xlogutils.h */
53 : : HotStandbyState standbyState = STANDBY_DISABLED;
54 : :
55 : : /*
56 : : * During XLOG replay, we may see XLOG records for incremental updates of
57 : : * pages that no longer exist, because their relation was later dropped or
58 : : * truncated. (Note: this is only possible when full_page_writes = OFF,
59 : : * since when it's ON, the first reference we see to a page should always
60 : : * be a full-page rewrite not an incremental update.) Rather than simply
61 : : * ignoring such records, we make a note of the referenced page, and then
62 : : * complain if we don't actually see a drop or truncate covering the page
63 : : * later in replay.
64 : : */
65 : : typedef struct xl_invalid_page_key
66 : : {
67 : : RelFileLocator locator; /* the relation */
68 : : ForkNumber forkno; /* the fork number */
69 : : BlockNumber blkno; /* the page */
70 : : } xl_invalid_page_key;
71 : :
72 : : typedef struct xl_invalid_page
73 : : {
74 : : xl_invalid_page_key key; /* hash key ... must be first */
75 : : bool present; /* page existed but contained zeroes */
76 : : } xl_invalid_page;
77 : :
78 : : static HTAB *invalid_page_tab = NULL;
79 : :
80 : : static int read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPagePtr,
81 : : int reqLen, XLogRecPtr targetRecPtr,
82 : : char *cur_page, bool wait_for_wal);
83 : :
84 : : /* Report a reference to an invalid page */
85 : : static void
648 rhaas@postgresql.org 86 :UBC 0 : report_invalid_page(int elevel, RelFileLocator locator, ForkNumber forkno,
87 : : BlockNumber blkno, bool present)
88 : : {
89 : 0 : char *path = relpathperm(locator, forkno);
90 : :
4517 heikki.linnakangas@i 91 [ # # ]: 0 : if (present)
92 [ # # ]: 0 : elog(elevel, "page %u of relation %s is uninitialized",
93 : : blkno, path);
94 : : else
95 [ # # ]: 0 : elog(elevel, "page %u of relation %s does not exist",
96 : : blkno, path);
97 : 0 : pfree(path);
98 : 0 : }
99 : :
100 : : /* Log a reference to an invalid page */
101 : : static void
648 rhaas@postgresql.org 102 :CBC 45 : log_invalid_page(RelFileLocator locator, ForkNumber forkno, BlockNumber blkno,
103 : : bool present)
104 : : {
105 : : xl_invalid_page_key key;
106 : : xl_invalid_page *hentry;
107 : : bool found;
108 : :
109 : : /*
110 : : * Once recovery has reached a consistent state, the invalid-page table
111 : : * should be empty and remain so. If a reference to an invalid page is
112 : : * found after consistency is reached, PANIC immediately. This might seem
113 : : * aggressive, but it's better than letting the invalid reference linger
114 : : * in the hash table until the end of recovery and PANIC there, which
115 : : * might come only much later if this is a standby server.
116 : : */
4510 heikki.linnakangas@i 117 [ - + ]: 45 : if (reachedConsistency)
118 : : {
648 rhaas@postgresql.org 119 :UBC 0 : report_invalid_page(WARNING, locator, forkno, blkno, present);
1544 fujii@postgresql.org 120 [ # # # # ]: 0 : elog(ignore_invalid_pages ? WARNING : PANIC,
121 : : "WAL contains references to invalid pages");
122 : : }
123 : :
124 : : /*
125 : : * Log references to invalid pages at DEBUG1 level. This allows some
126 : : * tracing of the cause (note the elog context mechanism will tell us
127 : : * something about the XLOG record that generated the reference).
128 : : */
1238 tgl@sss.pgh.pa.us 129 [ - + ]:CBC 45 : if (message_level_is_interesting(DEBUG1))
648 rhaas@postgresql.org 130 :UBC 0 : report_invalid_page(DEBUG1, locator, forkno, blkno, present);
131 : :
6575 tgl@sss.pgh.pa.us 132 [ + + ]:CBC 45 : if (invalid_page_tab == NULL)
133 : : {
134 : : /* create hash table when first needed */
135 : : HASHCTL ctl;
136 : :
137 : 1 : ctl.keysize = sizeof(xl_invalid_page_key);
138 : 1 : ctl.entrysize = sizeof(xl_invalid_page);
139 : :
140 : 1 : invalid_page_tab = hash_create("XLOG invalid-page table",
141 : : 100,
142 : : &ctl,
143 : : HASH_ELEM | HASH_BLOBS);
144 : : }
145 : :
146 : : /* we currently assume xl_invalid_page_key contains no padding */
648 rhaas@postgresql.org 147 : 45 : key.locator = locator;
5725 heikki.linnakangas@i 148 : 45 : key.forkno = forkno;
6575 tgl@sss.pgh.pa.us 149 : 45 : key.blkno = blkno;
150 : : hentry = (xl_invalid_page *)
433 peter@eisentraut.org 151 : 45 : hash_search(invalid_page_tab, &key, HASH_ENTER, &found);
152 : :
6575 tgl@sss.pgh.pa.us 153 [ + - ]: 45 : if (!found)
154 : : {
155 : : /* hash_search already filled in the key */
156 : 45 : hentry->present = present;
157 : : }
158 : : else
159 : : {
160 : : /* repeat reference ... leave "present" as it was */
161 : : }
162 : 45 : }
163 : :
164 : : /* Forget any invalid pages >= minblkno, because they've been dropped */
165 : : static void
648 rhaas@postgresql.org 166 : 28081 : forget_invalid_pages(RelFileLocator locator, ForkNumber forkno,
167 : : BlockNumber minblkno)
168 : : {
169 : : HASH_SEQ_STATUS status;
170 : : xl_invalid_page *hentry;
171 : :
6575 tgl@sss.pgh.pa.us 172 [ + + ]: 28081 : if (invalid_page_tab == NULL)
173 : 28065 : return; /* nothing to do */
174 : :
175 : 16 : hash_seq_init(&status, invalid_page_tab);
176 : :
177 [ + + ]: 601 : while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
178 : : {
648 rhaas@postgresql.org 179 [ + + + - : 585 : if (RelFileLocatorEquals(hentry->key.locator, locator) &&
+ - ]
5725 heikki.linnakangas@i 180 [ + - ]: 45 : hentry->key.forkno == forkno &&
6575 tgl@sss.pgh.pa.us 181 [ + - ]: 45 : hentry->key.blkno >= minblkno)
182 : : {
1238 183 [ - + ]: 45 : if (message_level_is_interesting(DEBUG2))
184 : : {
648 rhaas@postgresql.org 185 :UBC 0 : char *path = relpathperm(hentry->key.locator, forkno);
186 : :
5633 heikki.linnakangas@i 187 [ # # ]: 0 : elog(DEBUG2, "page %u of relation %s has been dropped",
188 : : hentry->key.blkno, path);
189 : 0 : pfree(path);
190 : : }
191 : :
6575 tgl@sss.pgh.pa.us 192 [ - + ]:CBC 45 : if (hash_search(invalid_page_tab,
433 peter@eisentraut.org 193 : 45 : &hentry->key,
194 : : HASH_REMOVE, NULL) == NULL)
6575 tgl@sss.pgh.pa.us 195 [ # # ]:UBC 0 : elog(ERROR, "hash table corrupted");
196 : : }
197 : : }
198 : : }
199 : :
200 : : /* Forget any invalid pages in a whole database */
201 : : static void
6575 tgl@sss.pgh.pa.us 202 :CBC 29 : forget_invalid_pages_db(Oid dbid)
203 : : {
204 : : HASH_SEQ_STATUS status;
205 : : xl_invalid_page *hentry;
206 : :
207 [ + - ]: 29 : if (invalid_page_tab == NULL)
208 : 29 : return; /* nothing to do */
209 : :
6575 tgl@sss.pgh.pa.us 210 :UBC 0 : hash_seq_init(&status, invalid_page_tab);
211 : :
212 [ # # ]: 0 : while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
213 : : {
648 rhaas@postgresql.org 214 [ # # ]: 0 : if (hentry->key.locator.dbOid == dbid)
215 : : {
1238 tgl@sss.pgh.pa.us 216 [ # # ]: 0 : if (message_level_is_interesting(DEBUG2))
217 : : {
648 rhaas@postgresql.org 218 : 0 : char *path = relpathperm(hentry->key.locator, hentry->key.forkno);
219 : :
5633 heikki.linnakangas@i 220 [ # # ]: 0 : elog(DEBUG2, "page %u of relation %s has been dropped",
221 : : hentry->key.blkno, path);
222 : 0 : pfree(path);
223 : : }
224 : :
6575 tgl@sss.pgh.pa.us 225 [ # # ]: 0 : if (hash_search(invalid_page_tab,
433 peter@eisentraut.org 226 : 0 : &hentry->key,
227 : : HASH_REMOVE, NULL) == NULL)
6575 tgl@sss.pgh.pa.us 228 [ # # ]: 0 : elog(ERROR, "hash table corrupted");
229 : : }
230 : : }
231 : : }
232 : :
233 : : /* Are there any unresolved references to invalid pages? */
234 : : bool
4517 heikki.linnakangas@i 235 :CBC 326 : XLogHaveInvalidPages(void)
236 : : {
237 [ - + - - ]: 326 : if (invalid_page_tab != NULL &&
4517 heikki.linnakangas@i 238 :UBC 0 : hash_get_num_entries(invalid_page_tab) > 0)
239 : 0 : return true;
4517 heikki.linnakangas@i 240 :CBC 326 : return false;
241 : : }
242 : :
243 : : /* Complain about any remaining invalid-page entries */
244 : : void
6575 tgl@sss.pgh.pa.us 245 : 145 : XLogCheckInvalidPages(void)
246 : : {
247 : : HASH_SEQ_STATUS status;
248 : : xl_invalid_page *hentry;
249 : 145 : bool foundone = false;
250 : :
251 [ + - ]: 145 : if (invalid_page_tab == NULL)
252 : 145 : return; /* nothing to do */
253 : :
6575 tgl@sss.pgh.pa.us 254 :UBC 0 : hash_seq_init(&status, invalid_page_tab);
255 : :
256 : : /*
257 : : * Our strategy is to emit WARNING messages for all remaining entries and
258 : : * only PANIC after we've dumped all the available info.
259 : : */
260 [ # # ]: 0 : while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
261 : : {
648 rhaas@postgresql.org 262 : 0 : report_invalid_page(WARNING, hentry->key.locator, hentry->key.forkno,
4517 heikki.linnakangas@i 263 : 0 : hentry->key.blkno, hentry->present);
6575 tgl@sss.pgh.pa.us 264 : 0 : foundone = true;
265 : : }
266 : :
267 [ # # ]: 0 : if (foundone)
1544 fujii@postgresql.org 268 [ # # # # ]: 0 : elog(ignore_invalid_pages ? WARNING : PANIC,
269 : : "WAL contains references to invalid pages");
270 : :
5785 heikki.linnakangas@i 271 : 0 : hash_destroy(invalid_page_tab);
272 : 0 : invalid_page_tab = NULL;
273 : : }
274 : :
275 : :
276 : : /*
277 : : * XLogReadBufferForRedo
278 : : * Read a page during XLOG replay
279 : : *
280 : : * Reads a block referenced by a WAL record into shared buffer cache, and
281 : : * determines what needs to be done to redo the changes to it. If the WAL
282 : : * record includes a full-page image of the page, it is restored.
283 : : *
284 : : * 'record.EndRecPtr' is compared to the page's LSN to determine if the record
285 : : * has already been replayed. 'block_id' is the ID number the block was
286 : : * registered with, when the WAL record was created.
287 : : *
288 : : * Returns one of the following:
289 : : *
290 : : * BLK_NEEDS_REDO - changes from the WAL record need to be applied
291 : : * BLK_DONE - block doesn't need replaying
292 : : * BLK_RESTORED - block was restored from a full-page image included in
293 : : * the record
294 : : * BLK_NOTFOUND - block was not found (because it was truncated away by
295 : : * an operation later in the WAL stream)
296 : : *
297 : : * On return, the buffer is locked in exclusive-mode, and returned in *buf.
298 : : * Note that the buffer is locked and returned even if it doesn't need
299 : : * replaying. (Getting the buffer lock is not really necessary during
300 : : * single-process crash recovery, but some subroutines such as MarkBufferDirty
301 : : * will complain if we don't have the lock. In hot standby mode it's
302 : : * definitely necessary.)
303 : : *
304 : : * Note: when a backup block is available in XLOG with the BKPIMAGE_APPLY flag
305 : : * set, we restore it, even if the page in the database appears newer. This
306 : : * is to protect ourselves against database pages that were partially or
307 : : * incorrectly written during a crash. We assume that the XLOG data must be
308 : : * good because it has passed a CRC check, while the database page might not
309 : : * be. This will force us to replay all subsequent modifications of the page
310 : : * that appear in XLOG, rather than possibly ignoring them as already
311 : : * applied, but that's not a huge drawback.
312 : : */
313 : : XLogRedoAction
3433 heikki.linnakangas@i 314 :CBC 3062232 : XLogReadBufferForRedo(XLogReaderState *record, uint8 block_id,
315 : : Buffer *buf)
316 : : {
317 : 3062232 : return XLogReadBufferForRedoExtended(record, block_id, RBM_NORMAL,
318 : : false, buf);
319 : : }
320 : :
321 : : /*
322 : : * Pin and lock a buffer referenced by a WAL record, for the purpose of
323 : : * re-initializing it.
324 : : */
325 : : Buffer
326 : 52723 : XLogInitBufferForRedo(XLogReaderState *record, uint8 block_id)
327 : : {
328 : : Buffer buf;
329 : :
330 : 52723 : XLogReadBufferForRedoExtended(record, block_id, RBM_ZERO_AND_LOCK, false,
331 : : &buf);
332 : 52723 : return buf;
333 : : }
334 : :
335 : : /*
336 : : * XLogReadBufferForRedoExtended
337 : : * Like XLogReadBufferForRedo, but with extra options.
338 : : *
339 : : * In RBM_ZERO_* modes, if the page doesn't exist, the relation is extended
340 : : * with all-zeroes pages up to the referenced block number. In
341 : : * RBM_ZERO_AND_LOCK and RBM_ZERO_AND_CLEANUP_LOCK modes, the return value
342 : : * is always BLK_NEEDS_REDO.
343 : : *
344 : : * (The RBM_ZERO_AND_CLEANUP_LOCK mode is redundant with the get_cleanup_lock
345 : : * parameter. Do not use an inconsistent combination!)
346 : : *
347 : : * If 'get_cleanup_lock' is true, a "cleanup lock" is acquired on the buffer
348 : : * using LockBufferForCleanup(), instead of a regular exclusive lock.
349 : : */
350 : : XLogRedoAction
351 : 3137812 : XLogReadBufferForRedoExtended(XLogReaderState *record,
352 : : uint8 block_id,
353 : : ReadBufferMode mode, bool get_cleanup_lock,
354 : : Buffer *buf)
355 : : {
356 : 3137812 : XLogRecPtr lsn = record->EndRecPtr;
357 : : RelFileLocator rlocator;
358 : : ForkNumber forknum;
359 : : BlockNumber blkno;
360 : : Buffer prefetch_buffer;
361 : : Page page;
362 : : bool zeromode;
363 : : bool willinit;
364 : :
648 rhaas@postgresql.org 365 [ - + ]: 3137812 : if (!XLogRecGetBlockTagExtended(record, block_id, &rlocator, &forknum, &blkno,
366 : : &prefetch_buffer))
367 : : {
368 : : /* Caller specified a bogus block_id */
734 tgl@sss.pgh.pa.us 369 [ # # ]:UBC 0 : elog(PANIC, "failed to locate backup block with ID %d in WAL record",
370 : : block_id);
371 : : }
372 : :
373 : : /*
374 : : * Make sure that if the block is marked with WILL_INIT, the caller is
375 : : * going to initialize it. And vice versa.
376 : : */
3191 heikki.linnakangas@i 377 [ + + + + ]:CBC 3137812 : zeromode = (mode == RBM_ZERO_AND_LOCK || mode == RBM_ZERO_AND_CLEANUP_LOCK);
758 tmunro@postgresql.or 378 : 3137812 : willinit = (XLogRecGetBlock(record, block_id)->flags & BKPBLOCK_WILL_INIT) != 0;
3191 heikki.linnakangas@i 379 [ + + - + ]: 3137812 : if (willinit && !zeromode)
3191 heikki.linnakangas@i 380 [ # # ]:UBC 0 : elog(PANIC, "block with WILL_INIT flag in WAL record must be zeroed by redo routine");
3191 heikki.linnakangas@i 381 [ + + - + ]:CBC 3137812 : if (!willinit && zeromode)
3191 heikki.linnakangas@i 382 [ # # ]:UBC 0 : elog(PANIC, "block to be initialized in redo routine must be marked with WILL_INIT flag in the WAL record");
383 : :
384 : : /* If it has a full-page image and it should be restored, do it. */
2622 rhaas@postgresql.org 385 [ + + ]:CBC 3137812 : if (XLogRecBlockImageApply(record, block_id))
386 : : {
387 [ - + ]: 56209 : Assert(XLogRecHasBlockImage(record, block_id));
648 388 [ + + ]: 56209 : *buf = XLogReadBufferExtended(rlocator, forknum, blkno,
389 : : get_cleanup_lock ? RBM_ZERO_AND_CLEANUP_LOCK : RBM_ZERO_AND_LOCK,
390 : : prefetch_buffer);
2916 kgrittn@postgresql.o 391 : 56209 : page = BufferGetPage(*buf);
3433 heikki.linnakangas@i 392 [ - + ]: 56209 : if (!RestoreBlockImage(record, block_id, page))
583 michael@paquier.xyz 393 [ # # ]:UBC 0 : ereport(ERROR,
394 : : (errcode(ERRCODE_INTERNAL_ERROR),
395 : : errmsg_internal("%s", record->errormsg_buf)));
396 : :
397 : : /*
398 : : * The page may be uninitialized. If so, we can't set the LSN because
399 : : * that would corrupt the page.
400 : : */
3433 heikki.linnakangas@i 401 [ + + ]:CBC 56209 : if (!PageIsNew(page))
402 : : {
403 : 56194 : PageSetLSN(page, lsn);
404 : : }
405 : :
406 : 56209 : MarkBufferDirty(*buf);
407 : :
408 : : /*
409 : : * At the end of crash recovery the init forks of unlogged relations
410 : : * are copied, without going through shared buffers. So we need to
411 : : * force the on-disk state of init forks to always be in sync with the
412 : : * state in shared buffers.
413 : : */
3048 andres@anarazel.de 414 [ + + ]: 56209 : if (forknum == INIT_FORKNUM)
415 : 26 : FlushOneBuffer(*buf);
416 : :
3532 heikki.linnakangas@i 417 : 56209 : return BLK_RESTORED;
418 : : }
419 : : else
420 : : {
648 rhaas@postgresql.org 421 : 3081603 : *buf = XLogReadBufferExtended(rlocator, forknum, blkno, mode, prefetch_buffer);
3532 heikki.linnakangas@i 422 [ + + ]: 3081603 : if (BufferIsValid(*buf))
423 : : {
3440 424 [ + + + + ]: 3081558 : if (mode != RBM_ZERO_AND_LOCK && mode != RBM_ZERO_AND_CLEANUP_LOCK)
425 : : {
426 [ + + ]: 3028611 : if (get_cleanup_lock)
427 : 9945 : LockBufferForCleanup(*buf);
428 : : else
429 : 3018666 : LockBuffer(*buf, BUFFER_LOCK_EXCLUSIVE);
430 : : }
2916 kgrittn@postgresql.o 431 [ - + ]: 3081558 : if (lsn <= PageGetLSN(BufferGetPage(*buf)))
3532 heikki.linnakangas@i 432 :UBC 0 : return BLK_DONE;
433 : : else
3532 heikki.linnakangas@i 434 :CBC 3081558 : return BLK_NEEDS_REDO;
435 : : }
436 : : else
437 : 45 : return BLK_NOTFOUND;
438 : : }
439 : : }
440 : :
441 : : /*
442 : : * XLogReadBufferExtended
443 : : * Read a page during XLOG replay
444 : : *
445 : : * This is functionally comparable to ReadBufferExtended. There's some
446 : : * differences in the behavior wrt. the "mode" argument:
447 : : *
448 : : * In RBM_NORMAL mode, if the page doesn't exist, or contains all-zeroes, we
449 : : * return InvalidBuffer. In this case the caller should silently skip the
450 : : * update on this page. (In this situation, we expect that the page was later
451 : : * dropped or truncated. If we don't see evidence of that later in the WAL
452 : : * sequence, we'll complain at the end of WAL replay.)
453 : : *
454 : : * In RBM_ZERO_* modes, if the page doesn't exist, the relation is extended
455 : : * with all-zeroes pages up to the given block number.
456 : : *
457 : : * In RBM_NORMAL_NO_LOG mode, we return InvalidBuffer if the page doesn't
458 : : * exist, and we don't check for all-zeroes. Thus, no log entry is made
459 : : * to imply that the page should be dropped or truncated later.
460 : : *
461 : : * Optionally, recent_buffer can be used to provide a hint about the location
462 : : * of the page in the buffer pool; it does not have to be correct, but avoids
463 : : * a buffer mapping table probe if it is.
464 : : *
465 : : * NB: A redo function should normally not call this directly. To get a page
466 : : * to modify, use XLogReadBufferForRedoExtended instead. It is important that
467 : : * all pages modified by a WAL record are registered in the WAL records, or
468 : : * they will be invisible to tools that need to know which pages are modified.
469 : : */
470 : : Buffer
648 rhaas@postgresql.org 471 : 3500890 : XLogReadBufferExtended(RelFileLocator rlocator, ForkNumber forknum,
472 : : BlockNumber blkno, ReadBufferMode mode,
473 : : Buffer recent_buffer)
474 : : {
475 : : BlockNumber lastblock;
476 : : Buffer buffer;
477 : : SMgrRelation smgr;
478 : :
6591 tgl@sss.pgh.pa.us 479 [ - + ]: 3500890 : Assert(blkno != P_NEW);
480 : :
481 : : /* Do we have a clue where the buffer might be already? */
738 tmunro@postgresql.or 482 [ + + + - ]: 3500890 : if (BufferIsValid(recent_buffer) &&
483 [ + + ]: 518831 : mode == RBM_NORMAL &&
648 rhaas@postgresql.org 484 : 518831 : ReadRecentBuffer(rlocator, forknum, blkno, recent_buffer))
485 : : {
738 tmunro@postgresql.or 486 : 516485 : buffer = recent_buffer;
487 : 516485 : goto recent_buffer_fast_path;
488 : : }
489 : :
490 : : /* Open the relation at smgr level */
42 heikki.linnakangas@i 491 :GNC 2984405 : smgr = smgropen(rlocator, INVALID_PROC_NUMBER);
492 : :
493 : : /*
494 : : * Create the target file if it doesn't already exist. This lets us cope
495 : : * if the replay sequence contains writes to a relation that is later
496 : : * deleted. (The original coding of this routine would instead suppress
497 : : * the writes, but that seems like it risks losing valuable data if the
498 : : * filesystem loses an inode during a crash. Better to write the data
499 : : * until we are actually told to delete the file.)
500 : : */
5625 heikki.linnakangas@i 501 :CBC 2984405 : smgrcreate(smgr, forknum, true);
502 : :
5725 503 : 2984405 : lastblock = smgrnblocks(smgr, forknum);
504 : :
6591 tgl@sss.pgh.pa.us 505 [ + + ]: 2984405 : if (blkno < lastblock)
506 : : {
507 : : /* page exists in file */
648 rhaas@postgresql.org 508 : 2936503 : buffer = ReadBufferWithoutRelcache(rlocator, forknum, blkno,
509 : : mode, NULL, true);
510 : : }
511 : : else
512 : : {
513 : : /* hm, page doesn't exist in file */
5644 heikki.linnakangas@i 514 [ + + ]: 47902 : if (mode == RBM_NORMAL)
515 : : {
648 rhaas@postgresql.org 516 : 45 : log_invalid_page(rlocator, forknum, blkno, false);
6575 tgl@sss.pgh.pa.us 517 : 45 : return InvalidBuffer;
518 : : }
3743 519 [ - + ]: 47857 : if (mode == RBM_NORMAL_NO_LOG)
3743 tgl@sss.pgh.pa.us 520 :UBC 0 : return InvalidBuffer;
521 : : /* OK to extend the file */
522 : : /* we do this in recovery only - no rel-extension lock needed */
6591 tgl@sss.pgh.pa.us 523 [ - + ]:CBC 47857 : Assert(InRecovery);
235 tmunro@postgresql.or 524 : 47857 : buffer = ExtendBufferedRelTo(BMR_SMGR(smgr, RELPERSISTENCE_PERMANENT),
525 : : forknum,
526 : : NULL,
527 : : EB_PERFORMING_RECOVERY |
528 : : EB_SKIP_EXTENSION_LOCK,
529 : : blkno + 1,
530 : : mode);
531 : : }
532 : :
738 533 : 3500845 : recent_buffer_fast_path:
5644 heikki.linnakangas@i 534 [ + + ]: 3500845 : if (mode == RBM_NORMAL)
535 : : {
536 : : /* check that page has been initialized */
2916 kgrittn@postgresql.o 537 : 3021286 : Page page = (Page) BufferGetPage(buffer);
538 : :
539 : : /*
540 : : * We assume that PageIsNew is safe without a lock. During recovery,
541 : : * there should be no other backends that could modify the buffer at
542 : : * the same time.
543 : : */
5754 tgl@sss.pgh.pa.us 544 [ - + ]: 3021286 : if (PageIsNew(page))
545 : : {
5563 heikki.linnakangas@i 546 :UBC 0 : ReleaseBuffer(buffer);
648 rhaas@postgresql.org 547 : 0 : log_invalid_page(rlocator, forknum, blkno, true);
6575 tgl@sss.pgh.pa.us 548 : 0 : return InvalidBuffer;
549 : : }
550 : : }
551 : :
6668 neilc@samurai.com 552 :CBC 3500845 : return buffer;
553 : : }
554 : :
555 : : /*
556 : : * Struct actually returned by CreateFakeRelcacheEntry, though the declared
557 : : * return type is Relation.
558 : : */
559 : : typedef struct
560 : : {
561 : : RelationData reldata; /* Note: this must be first */
562 : : FormData_pg_class pgc;
563 : : } FakeRelCacheEntryData;
564 : :
565 : : typedef FakeRelCacheEntryData *FakeRelCacheEntry;
566 : :
567 : : /*
568 : : * Create a fake relation cache entry for a physical relation
569 : : *
570 : : * It's often convenient to use the same functions in XLOG replay as in the
571 : : * main codepath, but those functions typically work with a relcache entry.
572 : : * We don't have a working relation cache during XLOG replay, but this
573 : : * function can be used to create a fake relcache entry instead. Only the
574 : : * fields related to physical storage, like rd_rel, are initialized, so the
575 : : * fake entry is only usable in low-level operations like ReadBuffer().
576 : : *
577 : : * This is also used for syncing WAL-skipped files.
578 : : *
579 : : * Caller must free the returned entry with FreeFakeRelcacheEntry().
580 : : */
581 : : Relation
648 rhaas@postgresql.org 582 : 51167 : CreateFakeRelcacheEntry(RelFileLocator rlocator)
583 : : {
584 : : FakeRelCacheEntry fakeentry;
585 : : Relation rel;
586 : :
587 : : /* Allocate the Relation struct and all related space in one block. */
5785 heikki.linnakangas@i 588 : 51167 : fakeentry = palloc0(sizeof(FakeRelCacheEntryData));
589 : 51167 : rel = (Relation) fakeentry;
590 : :
591 : 51167 : rel->rd_rel = &fakeentry->pgc;
648 rhaas@postgresql.org 592 : 51167 : rel->rd_locator = rlocator;
593 : :
594 : : /*
595 : : * We will never be working with temp rels during recovery or while
596 : : * syncing WAL-skipped files.
597 : : */
42 heikki.linnakangas@i 598 :GNC 51167 : rel->rd_backend = INVALID_PROC_NUMBER;
599 : :
600 : : /* It must be a permanent table here */
4230 rhaas@postgresql.org 601 :CBC 51167 : rel->rd_rel->relpersistence = RELPERSISTENCE_PERMANENT;
602 : :
603 : : /* We don't know the name of the relation; use relfilenumber instead */
564 604 : 51167 : sprintf(RelationGetRelationName(rel), "%u", rlocator.relNumber);
605 : :
606 : : /*
607 : : * We set up the lockRelId in case anything tries to lock the dummy
608 : : * relation. Note that this is fairly bogus since relNumber may be
609 : : * different from the relation's OID. It shouldn't really matter though.
610 : : * In recovery, we are running by ourselves and can't have any lock
611 : : * conflicts. While syncing, we already hold AccessExclusiveLock.
612 : : */
648 613 : 51167 : rel->rd_lockInfo.lockRelId.dbId = rlocator.dbOid;
564 614 : 51167 : rel->rd_lockInfo.lockRelId.relId = rlocator.relNumber;
615 : :
616 : : /*
617 : : * Set up a non-pinned SMgrRelation reference, so that we don't need to
618 : : * worry about unpinning it on error.
619 : : */
42 heikki.linnakangas@i 620 :GNC 51167 : rel->rd_smgr = smgropen(rlocator, INVALID_PROC_NUMBER);
621 : :
5785 heikki.linnakangas@i 622 :CBC 51167 : return rel;
623 : : }
624 : :
625 : : /*
626 : : * Free a fake relation cache entry.
627 : : */
628 : : void
629 : 51167 : FreeFakeRelcacheEntry(Relation fakerel)
630 : : {
631 : 51167 : pfree(fakerel);
8577 vadim4o@yahoo.com 632 : 51167 : }
633 : :
634 : : /*
635 : : * Drop a relation during XLOG replay
636 : : *
637 : : * This is called when the relation is about to be deleted; we need to remove
638 : : * any open "invalid-page" records for the relation.
639 : : */
640 : : void
648 rhaas@postgresql.org 641 : 28028 : XLogDropRelation(RelFileLocator rlocator, ForkNumber forknum)
642 : : {
643 : 28028 : forget_invalid_pages(rlocator, forknum, 0);
7368 tgl@sss.pgh.pa.us 644 : 28028 : }
645 : :
646 : : /*
647 : : * Drop a whole database during XLOG replay
648 : : *
649 : : * As above, but for DROP DATABASE instead of dropping a single rel
650 : : */
651 : : void
6591 652 : 29 : XLogDropDatabase(Oid dbid)
653 : : {
654 : : /*
655 : : * This is unnecessarily heavy-handed, as it will close SMgrRelation
656 : : * objects for other databases as well. DROP DATABASE occurs seldom enough
657 : : * that it's not worth introducing a variant of smgrdestroy for just this
658 : : * purpose.
659 : : */
74 heikki.linnakangas@i 660 :GNC 29 : smgrdestroyall();
661 : :
6575 tgl@sss.pgh.pa.us 662 :CBC 29 : forget_invalid_pages_db(dbid);
663 : 29 : }
664 : :
665 : : /*
666 : : * Truncate a relation during XLOG replay
667 : : *
668 : : * We need to clean up any open "invalid-page" records for the dropped pages.
669 : : */
670 : : void
648 rhaas@postgresql.org 671 : 53 : XLogTruncateRelation(RelFileLocator rlocator, ForkNumber forkNum,
672 : : BlockNumber nblocks)
673 : : {
674 : 53 : forget_invalid_pages(rlocator, forkNum, nblocks);
6591 tgl@sss.pgh.pa.us 675 : 53 : }
676 : :
677 : : /*
678 : : * Determine which timeline to read an xlog page from and set the
679 : : * XLogReaderState's currTLI to that timeline ID.
680 : : *
681 : : * We care about timelines in xlogreader when we might be reading xlog
682 : : * generated prior to a promotion, either if we're currently a standby in
683 : : * recovery or if we're a promoted primary reading xlogs generated by the old
684 : : * primary before our promotion.
685 : : *
686 : : * wantPage must be set to the start address of the page to read and
687 : : * wantLength to the amount of the page that will be read, up to
688 : : * XLOG_BLCKSZ. If the amount to be read isn't known, pass XLOG_BLCKSZ.
689 : : *
690 : : * The currTLI argument should be the system-wide current timeline.
691 : : * Note that this may be different from state->currTLI, which is the timeline
692 : : * from which the caller is currently reading previous xlog records.
693 : : *
694 : : * We switch to an xlog segment from the new timeline eagerly when on a
695 : : * historical timeline, as soon as we reach the start of the xlog segment
696 : : * containing the timeline switch. The server copied the segment to the new
697 : : * timeline so all the data up to the switch point is the same, but there's no
698 : : * guarantee the old segment will still exist. It may have been deleted or
699 : : * renamed with a .partial suffix so we can't necessarily keep reading from
700 : : * the old TLI even though tliSwitchPoint says it's OK.
701 : : *
702 : : * We can't just check the timeline when we read a page on a different segment
703 : : * to the last page. We could've received a timeline switch from a cascading
704 : : * upstream, so the current segment ends abruptly (possibly getting renamed to
705 : : * .partial) and we have to switch to a new one. Even in the middle of reading
706 : : * a page we could have to dump the cached page and switch to a new TLI.
707 : : *
708 : : * Because of this, callers MAY NOT assume that currTLI is the timeline that
709 : : * will be in a page's xlp_tli; the page may begin on an older timeline or we
710 : : * might be reading from historical timeline data on a segment that's been
711 : : * copied to a new timeline.
712 : : *
713 : : * The caller must also make sure it doesn't read past the current replay
714 : : * position (using GetXLogReplayRecPtr) if executing in recovery, so it
715 : : * doesn't fail to notice that the current timeline became historical.
716 : : */
717 : : void
891 rhaas@postgresql.org 718 : 51165 : XLogReadDetermineTimeline(XLogReaderState *state, XLogRecPtr wantPage,
719 : : uint32 wantLength, TimeLineID currTLI)
720 : : {
1070 tmunro@postgresql.or 721 : 51165 : const XLogRecPtr lastReadPage = (state->seg.ws_segno *
722 : 51165 : state->segcxt.ws_segsize + state->segoff);
723 : :
2580 simon@2ndQuadrant.co 724 [ + - - + ]: 51165 : Assert(wantPage != InvalidXLogRecPtr && wantPage % XLOG_BLCKSZ == 0);
725 [ - + ]: 51165 : Assert(wantLength <= XLOG_BLCKSZ);
726 [ - + - - ]: 51165 : Assert(state->readLen == 0 || state->readLen <= XLOG_BLCKSZ);
891 rhaas@postgresql.org 727 [ - + ]: 51165 : Assert(currTLI != 0);
728 : :
729 : : /*
730 : : * If the desired page is currently read in and valid, we have nothing to
731 : : * do.
732 : : *
733 : : * The caller should've ensured that it didn't previously advance readOff
734 : : * past the valid limit of this timeline, so it doesn't matter if the
735 : : * current TLI has since become historical.
736 : : */
2580 simon@2ndQuadrant.co 737 [ + + ]: 51165 : if (lastReadPage == wantPage &&
1070 tmunro@postgresql.or 738 [ - + ]: 2162 : state->readLen != 0 &&
2524 bruce@momjian.us 739 [ # # ]:UBC 0 : lastReadPage + state->readLen >= wantPage + Min(wantLength, XLOG_BLCKSZ - 1))
2580 simon@2ndQuadrant.co 740 : 0 : return;
741 : :
742 : : /*
743 : : * If we're reading from the current timeline, it hasn't become historical
744 : : * and the page we're reading is after the last page read, we can again
745 : : * just carry on. (Seeking backwards requires a check to make sure the
746 : : * older page isn't on a prior timeline).
747 : : *
748 : : * currTLI might've become historical since the caller obtained the value,
749 : : * but the caller is required not to read past the flush limit it saw at
750 : : * the time it looked up the timeline. There's nothing we can do about it
751 : : * if StartupXLOG() renames it to .partial concurrently.
752 : : */
891 rhaas@postgresql.org 753 [ + + + + ]:CBC 51165 : if (state->currTLI == currTLI && wantPage >= lastReadPage)
754 : : {
2580 simon@2ndQuadrant.co 755 [ - + ]: 48078 : Assert(state->currTLIValidUntil == InvalidXLogRecPtr);
756 : 48078 : return;
757 : : }
758 : :
759 : : /*
760 : : * If we're just reading pages from a previously validated historical
761 : : * timeline and the timeline we're reading from is valid until the end of
762 : : * the current segment we can just keep reading.
763 : : */
764 [ + + ]: 3087 : if (state->currTLIValidUntil != InvalidXLogRecPtr &&
891 rhaas@postgresql.org 765 [ + - ]: 1697 : state->currTLI != currTLI &&
2580 simon@2ndQuadrant.co 766 [ + - ]: 1697 : state->currTLI != 0 &&
1664 alvherre@alvh.no-ip. 767 : 1697 : ((wantPage + wantLength) / state->segcxt.ws_segsize) <
768 [ + + ]: 1697 : (state->currTLIValidUntil / state->segcxt.ws_segsize))
2580 simon@2ndQuadrant.co 769 : 1694 : return;
770 : :
771 : : /*
772 : : * If we reach this point we're either looking up a page for random
773 : : * access, the current timeline just became historical, or we're reading
774 : : * from a new segment containing a timeline switch. In all cases we need
775 : : * to determine the newest timeline on the segment.
776 : : *
777 : : * If it's the current timeline we can just keep reading from here unless
778 : : * we detect a timeline switch that makes the current timeline historical.
779 : : * If it's a historical timeline we can read all the segment on the newest
780 : : * timeline because it contains all the old timelines' data too. So only
781 : : * one switch check is required.
782 : : */
783 : : {
784 : : /*
785 : : * We need to re-read the timeline history in case it's been changed
786 : : * by a promotion or replay from a cascaded replica.
787 : : */
891 rhaas@postgresql.org 788 : 1393 : List *timelineHistory = readTimeLineHistory(currTLI);
789 : : XLogRecPtr endOfSegment;
790 : :
1664 alvherre@alvh.no-ip. 791 : 1393 : endOfSegment = ((wantPage / state->segcxt.ws_segsize) + 1) *
792 : 1393 : state->segcxt.ws_segsize - 1;
793 [ - + ]: 1393 : Assert(wantPage / state->segcxt.ws_segsize ==
794 : : endOfSegment / state->segcxt.ws_segsize);
795 : :
796 : : /*
797 : : * Find the timeline of the last LSN on the segment containing
798 : : * wantPage.
799 : : */
2580 simon@2ndQuadrant.co 800 : 1393 : state->currTLI = tliOfPointInHistory(endOfSegment, timelineHistory);
801 : 1393 : state->currTLIValidUntil = tliSwitchPoint(state->currTLI, timelineHistory,
802 : : &state->nextTLI);
803 : :
804 [ + + - + ]: 1393 : Assert(state->currTLIValidUntil == InvalidXLogRecPtr ||
805 : : wantPage + wantLength < state->currTLIValidUntil);
806 : :
807 : 1393 : list_free_deep(timelineHistory);
808 : :
809 [ - + ]: 1393 : elog(DEBUG3, "switched to timeline %u valid until %X/%X",
810 : : state->currTLI,
811 : : LSN_FORMAT_ARGS(state->currTLIValidUntil));
812 : : }
813 : : }
814 : :
815 : : /* XLogReaderRoutine->segment_open callback for local pg_wal files */
816 : : void
1437 alvherre@alvh.no-ip. 817 : 923 : wal_segment_open(XLogReaderState *state, XLogSegNo nextSegNo,
818 : : TimeLineID *tli_p)
819 : : {
1602 820 : 923 : TimeLineID tli = *tli_p;
821 : : char path[MAXPGPATH];
822 : :
1432 823 : 923 : XLogFilePath(path, tli, nextSegNo, state->segcxt.ws_segsize);
824 : 923 : state->seg.ws_file = BasicOpenFile(path, O_RDONLY | PG_BINARY);
825 [ + - ]: 923 : if (state->seg.ws_file >= 0)
826 : 923 : return;
827 : :
1602 alvherre@alvh.no-ip. 828 [ # # ]:UBC 0 : if (errno == ENOENT)
829 [ # # ]: 0 : ereport(ERROR,
830 : : (errcode_for_file_access(),
831 : : errmsg("requested WAL segment %s has already been removed",
832 : : path)));
833 : : else
834 [ # # ]: 0 : ereport(ERROR,
835 : : (errcode_for_file_access(),
836 : : errmsg("could not open file \"%s\": %m",
837 : : path)));
838 : : }
839 : :
840 : : /* stock XLogReaderRoutine->segment_close callback */
841 : : void
1437 alvherre@alvh.no-ip. 842 :CBC 9827 : wal_segment_close(XLogReaderState *state)
843 : : {
844 : 9827 : close(state->seg.ws_file);
845 : : /* need to check errno? */
846 : 9827 : state->seg.ws_file = -1;
847 : 9827 : }
848 : :
849 : : /*
850 : : * XLogReaderRoutine->page_read callback for reading local xlog files
851 : : *
852 : : * Public because it would likely be very helpful for someone writing another
853 : : * output method outside walsender, e.g. in a bgworker.
854 : : *
855 : : * TODO: The walsender has its own version of this, but it relies on the
856 : : * walsender's latch being set whenever WAL is flushed. No such infrastructure
857 : : * exists for normal backends, so we have to do a check/sleep/repeat style of
858 : : * loop for now.
859 : : */
860 : : int
1070 tmunro@postgresql.or 861 : 21280 : read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr,
862 : : int reqLen, XLogRecPtr targetRecPtr, char *cur_page)
863 : : {
737 jdavis@postgresql.or 864 : 21280 : return read_local_xlog_page_guts(state, targetPagePtr, reqLen,
865 : : targetRecPtr, cur_page, true);
866 : : }
867 : :
868 : : /*
869 : : * Same as read_local_xlog_page except that it doesn't wait for future WAL
870 : : * to be available.
871 : : */
872 : : int
873 : 3826 : read_local_xlog_page_no_wait(XLogReaderState *state, XLogRecPtr targetPagePtr,
874 : : int reqLen, XLogRecPtr targetRecPtr,
875 : : char *cur_page)
876 : : {
877 : 3826 : return read_local_xlog_page_guts(state, targetPagePtr, reqLen,
878 : : targetRecPtr, cur_page, false);
879 : : }
880 : :
881 : : /*
882 : : * Implementation of read_local_xlog_page and its no wait version.
883 : : */
884 : : static int
885 : 25106 : read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPagePtr,
886 : : int reqLen, XLogRecPtr targetRecPtr,
887 : : char *cur_page, bool wait_for_wal)
888 : : {
889 : : XLogRecPtr read_upto,
890 : : loc;
891 : : TimeLineID tli;
892 : : int count;
893 : : WALReadError errinfo;
894 : : TimeLineID currTLI;
895 : :
3007 simon@2ndQuadrant.co 896 : 25106 : loc = targetPagePtr + reqLen;
897 : :
898 : : /* Loop waiting for xlog to be available if necessary */
899 : : while (1)
900 : : {
901 : : /*
902 : : * Determine the limit of xlog we can currently read to, and what the
903 : : * most recent timeline is.
904 : : */
2902 alvherre@alvh.no-ip. 905 [ + + ]: 25787 : if (!RecoveryInProgress())
891 rhaas@postgresql.org 906 : 25006 : read_upto = GetFlushRecPtr(&currTLI);
907 : : else
908 : 781 : read_upto = GetXLogReplayRecPtr(&currTLI);
909 : 25787 : tli = currTLI;
910 : :
911 : : /*
912 : : * Check which timeline to get the record from.
913 : : *
914 : : * We have to do it each time through the loop because if we're in
915 : : * recovery as a cascading standby, the current timeline might've
916 : : * become historical. We can't rely on RecoveryInProgress() because in
917 : : * a standby configuration like
918 : : *
919 : : * A => B => C
920 : : *
921 : : * if we're a logical decoding session on C, and B gets promoted, our
922 : : * timeline will change while we remain in recovery.
923 : : *
924 : : * We can't just keep reading from the old timeline as the last WAL
925 : : * archive in the timeline will get renamed to .partial by
926 : : * StartupXLOG().
927 : : *
928 : : * If that happens after our caller determined the TLI but before we
929 : : * actually read the xlog page, we might still try to read from the
930 : : * old (now renamed) segment and fail. There's not much we can do
931 : : * about this, but it can only happen when we're a leaf of a cascading
932 : : * standby whose primary gets promoted while we're decoding, so a
933 : : * one-off ERROR isn't too bad.
934 : : */
935 : 25787 : XLogReadDetermineTimeline(state, targetPagePtr, reqLen, tli);
936 : :
937 [ + + ]: 25787 : if (state->currTLI == currTLI)
938 : : {
939 : :
2580 simon@2ndQuadrant.co 940 [ + + ]: 24090 : if (loc <= read_upto)
941 : 23399 : break;
942 : :
943 : : /* If asked, let's not wait for future WAL. */
737 jdavis@postgresql.or 944 [ + + ]: 691 : if (!wait_for_wal)
945 : : {
946 : : ReadLocalXLogPageNoWaitPrivate *private_data;
947 : :
948 : : /*
949 : : * Inform the caller of read_local_xlog_page_no_wait that the
950 : : * end of WAL has been reached.
951 : : */
715 952 : 10 : private_data = (ReadLocalXLogPageNoWaitPrivate *)
953 : : state->private_data;
954 : 10 : private_data->end_of_wal = true;
737 955 : 10 : break;
956 : : }
957 : :
2580 simon@2ndQuadrant.co 958 [ - + ]: 681 : CHECK_FOR_INTERRUPTS();
959 : 681 : pg_usleep(1000L);
960 : : }
961 : : else
962 : : {
963 : : /*
964 : : * We're on a historical timeline, so limit reading to the switch
965 : : * point where we moved to the next timeline.
966 : : *
967 : : * We don't need to GetFlushRecPtr or GetXLogReplayRecPtr. We know
968 : : * about the new timeline, so we must've received past the end of
969 : : * it.
970 : : */
971 : 1697 : read_upto = state->currTLIValidUntil;
972 : :
973 : : /*
974 : : * Setting tli to our wanted record's TLI is slightly wrong; the
975 : : * page might begin on an older timeline if it contains a timeline
976 : : * switch, since its xlog segment will have been copied from the
977 : : * prior timeline. This is pretty harmless though, as nothing
978 : : * cares so long as the timeline doesn't go backwards. We should
979 : : * read the page header instead; FIXME someday.
980 : : */
1602 alvherre@alvh.no-ip. 981 : 1697 : tli = state->currTLI;
982 : :
983 : : /* No need to wait on a historical timeline */
2580 simon@2ndQuadrant.co 984 : 1697 : break;
985 : : }
986 : : }
987 : :
2937 alvherre@alvh.no-ip. 988 [ + + ]: 25106 : if (targetPagePtr + XLOG_BLCKSZ <= read_upto)
989 : : {
990 : : /*
991 : : * more than one block available; read only that block, have caller
992 : : * come back if they need more.
993 : : */
3007 simon@2ndQuadrant.co 994 : 24319 : count = XLOG_BLCKSZ;
995 : : }
2937 alvherre@alvh.no-ip. 996 [ + + ]: 787 : else if (targetPagePtr + reqLen > read_upto)
997 : : {
998 : : /* not enough data there */
1070 tmunro@postgresql.or 999 : 10 : return -1;
1000 : : }
1001 : : else
1002 : : {
1003 : : /* enough bytes available to satisfy the request */
2937 alvherre@alvh.no-ip. 1004 : 777 : count = read_upto - targetPagePtr;
1005 : : }
1006 : :
58 jdavis@postgresql.or 1007 [ - + ]:GNC 25096 : if (!WALRead(state, cur_page, targetPagePtr, count, tli,
1008 : : &errinfo))
1602 alvherre@alvh.no-ip. 1009 :UBC 0 : WALReadRaiseError(&errinfo);
1010 : :
1011 : : /* number of valid bytes in the buffer */
1070 tmunro@postgresql.or 1012 :CBC 25096 : return count;
1013 : : }
1014 : :
1015 : : /*
1016 : : * Backend-specific convenience code to handle read errors encountered by
1017 : : * WALRead().
1018 : : */
1019 : : void
1602 alvherre@alvh.no-ip. 1020 :UBC 0 : WALReadRaiseError(WALReadError *errinfo)
1021 : : {
1022 : 0 : WALOpenSegment *seg = &errinfo->wre_seg;
1023 : : char fname[MAXFNAMELEN];
1024 : :
1594 michael@paquier.xyz 1025 : 0 : XLogFileName(fname, seg->ws_tli, seg->ws_segno, wal_segment_size);
1026 : :
1602 alvherre@alvh.no-ip. 1027 [ # # ]: 0 : if (errinfo->wre_read < 0)
1028 : : {
1029 : 0 : errno = errinfo->wre_errno;
1030 [ # # ]: 0 : ereport(ERROR,
1031 : : (errcode_for_file_access(),
1032 : : errmsg("could not read from WAL segment %s, offset %d: %m",
1033 : : fname, errinfo->wre_off)));
1034 : : }
1035 [ # # ]: 0 : else if (errinfo->wre_read == 0)
1036 : : {
1037 [ # # ]: 0 : ereport(ERROR,
1038 : : (errcode(ERRCODE_DATA_CORRUPTED),
1039 : : errmsg("could not read from WAL segment %s, offset %d: read %d of %d",
1040 : : fname, errinfo->wre_off, errinfo->wre_read,
1041 : : errinfo->wre_req)));
1042 : : }
1043 : 0 : }
|
