Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * relmapper.c
4 : : * Catalog-to-filenumber mapping
5 : : *
6 : : * For most tables, the physical file underlying the table is specified by
7 : : * pg_class.relfilenode. However, that obviously won't work for pg_class
8 : : * itself, nor for the other "nailed" catalogs for which we have to be able
9 : : * to set up working Relation entries without access to pg_class. It also
10 : : * does not work for shared catalogs, since there is no practical way to
11 : : * update other databases' pg_class entries when relocating a shared catalog.
12 : : * Therefore, for these special catalogs (henceforth referred to as "mapped
13 : : * catalogs") we rely on a separately maintained file that shows the mapping
14 : : * from catalog OIDs to filenumbers. Each database has a map file for
15 : : * its local mapped catalogs, and there is a separate map file for shared
16 : : * catalogs. Mapped catalogs have zero in their pg_class.relfilenode entries.
17 : : *
18 : : * Relocation of a normal table is committed (ie, the new physical file becomes
19 : : * authoritative) when the pg_class row update commits. For mapped catalogs,
20 : : * the act of updating the map file is effectively commit of the relocation.
21 : : * We postpone the file update till just before commit of the transaction
22 : : * doing the rewrite, but there is necessarily a window between. Therefore
23 : : * mapped catalogs can only be relocated by operations such as VACUUM FULL
24 : : * and CLUSTER, which make no transactionally-significant changes: it must be
25 : : * safe for the new file to replace the old, even if the transaction itself
26 : : * aborts. An important factor here is that the indexes and toast table of
27 : : * a mapped catalog must also be mapped, so that the rewrites/relocations of
28 : : * all these files commit in a single map file update rather than being tied
29 : : * to transaction commit.
30 : : *
31 : : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
32 : : * Portions Copyright (c) 1994, Regents of the University of California
33 : : *
34 : : *
35 : : * IDENTIFICATION
36 : : * src/backend/utils/cache/relmapper.c
37 : : *
38 : : *-------------------------------------------------------------------------
39 : : */
40 : : #include "postgres.h"
41 : :
42 : : #include <fcntl.h>
43 : : #include <sys/stat.h>
44 : : #include <unistd.h>
45 : :
46 : : #include "access/xact.h"
47 : : #include "access/xlog.h"
48 : : #include "access/xloginsert.h"
49 : : #include "catalog/pg_tablespace.h"
50 : : #include "catalog/storage.h"
51 : : #include "miscadmin.h"
52 : : #include "pgstat.h"
53 : : #include "storage/fd.h"
54 : : #include "storage/lwlock.h"
55 : : #include "utils/inval.h"
56 : : #include "utils/relmapper.h"
57 : :
58 : :
59 : : /*
60 : : * The map file is critical data: we have no automatic method for recovering
61 : : * from loss or corruption of it. We use a CRC so that we can detect
62 : : * corruption. Since the file might be more than one standard-size disk
63 : : * sector in size, we cannot rely on overwrite-in-place. Instead, we generate
64 : : * a new file and rename it into place, atomically replacing the original file.
65 : : *
66 : : * Entries in the mappings[] array are in no particular order. We could
67 : : * speed searching by insisting on OID order, but it really shouldn't be
68 : : * worth the trouble given the intended size of the mapping sets.
69 : : */
70 : : #define RELMAPPER_FILENAME "pg_filenode.map"
71 : : #define RELMAPPER_TEMP_FILENAME "pg_filenode.map.tmp"
72 : :
73 : : #define RELMAPPER_FILEMAGIC 0x592717 /* version ID value */
74 : :
75 : : /*
76 : : * There's no need for this constant to have any particular value, and we
77 : : * can raise it as necessary if we end up with more mapped relations. For
78 : : * now, we just pick a round number that is modestly larger than the expected
79 : : * number of mappings.
80 : : */
81 : : #define MAX_MAPPINGS 64
82 : :
83 : : typedef struct RelMapping
84 : : {
85 : : Oid mapoid; /* OID of a catalog */
86 : : RelFileNumber mapfilenumber; /* its rel file number */
87 : : } RelMapping;
88 : :
89 : : typedef struct RelMapFile
90 : : {
91 : : int32 magic; /* always RELMAPPER_FILEMAGIC */
92 : : int32 num_mappings; /* number of valid RelMapping entries */
93 : : RelMapping mappings[MAX_MAPPINGS];
94 : : pg_crc32c crc; /* CRC of all above */
95 : : } RelMapFile;
96 : :
97 : : /*
98 : : * State for serializing local and shared relmappings for parallel workers
99 : : * (active states only). See notes on active_* and pending_* updates state.
100 : : */
101 : : typedef struct SerializedActiveRelMaps
102 : : {
103 : : RelMapFile active_shared_updates;
104 : : RelMapFile active_local_updates;
105 : : } SerializedActiveRelMaps;
106 : :
107 : : /*
108 : : * The currently known contents of the shared map file and our database's
109 : : * local map file are stored here. These can be reloaded from disk
110 : : * immediately whenever we receive an update sinval message.
111 : : */
112 : : static RelMapFile shared_map;
113 : : static RelMapFile local_map;
114 : :
115 : : /*
116 : : * We use the same RelMapFile data structure to track uncommitted local
117 : : * changes in the mappings (but note the magic and crc fields are not made
118 : : * valid in these variables). Currently, map updates are not allowed within
119 : : * subtransactions, so one set of transaction-level changes is sufficient.
120 : : *
121 : : * The active_xxx variables contain updates that are valid in our transaction
122 : : * and should be honored by RelationMapOidToFilenumber. The pending_xxx
123 : : * variables contain updates we have been told about that aren't active yet;
124 : : * they will become active at the next CommandCounterIncrement. This setup
125 : : * lets map updates act similarly to updates of pg_class rows, ie, they
126 : : * become visible only at the next CommandCounterIncrement boundary.
127 : : *
128 : : * Active shared and active local updates are serialized by the parallel
129 : : * infrastructure, and deserialized within parallel workers.
130 : : */
131 : : static RelMapFile active_shared_updates;
132 : : static RelMapFile active_local_updates;
133 : : static RelMapFile pending_shared_updates;
134 : : static RelMapFile pending_local_updates;
135 : :
136 : :
137 : : /* non-export function prototypes */
138 : : static void apply_map_update(RelMapFile *map, Oid relationId,
139 : : RelFileNumber fileNumber, bool add_okay);
140 : : static void merge_map_updates(RelMapFile *map, const RelMapFile *updates,
141 : : bool add_okay);
142 : : static void load_relmap_file(bool shared, bool lock_held);
143 : : static void read_relmap_file(RelMapFile *map, char *dbpath, bool lock_held,
144 : : int elevel);
145 : : static void write_relmap_file(RelMapFile *newmap, bool write_wal,
146 : : bool send_sinval, bool preserve_files,
147 : : Oid dbid, Oid tsid, const char *dbpath);
148 : : static void perform_relmap_update(bool shared, const RelMapFile *updates);
149 : :
150 : :
151 : : /*
152 : : * RelationMapOidToFilenumber
153 : : *
154 : : * The raison d' etre ... given a relation OID, look up its filenumber.
155 : : *
156 : : * Although shared and local relation OIDs should never overlap, the caller
157 : : * always knows which we need --- so pass that information to avoid useless
158 : : * searching.
159 : : *
160 : : * Returns InvalidRelFileNumber if the OID is not known (which should never
161 : : * happen, but the caller is in a better position to report a meaningful
162 : : * error).
163 : : */
164 : : RelFileNumber
648 rhaas@postgresql.org 165 :CBC 704888 : RelationMapOidToFilenumber(Oid relationId, bool shared)
166 : : {
167 : : const RelMapFile *map;
168 : : int32 i;
169 : :
170 : : /* If there are active updates, believe those over the main maps */
5180 tgl@sss.pgh.pa.us 171 [ + + ]: 704888 : if (shared)
172 : : {
173 : 447529 : map = &active_shared_updates;
174 [ + + ]: 449056 : for (i = 0; i < map->num_mappings; i++)
175 : : {
176 [ + + ]: 2306 : if (relationId == map->mappings[i].mapoid)
648 rhaas@postgresql.org 177 : 779 : return map->mappings[i].mapfilenumber;
178 : : }
5180 tgl@sss.pgh.pa.us 179 : 446750 : map = &shared_map;
180 [ + - ]: 11520860 : for (i = 0; i < map->num_mappings; i++)
181 : : {
182 [ + + ]: 11520860 : if (relationId == map->mappings[i].mapoid)
648 rhaas@postgresql.org 183 : 446750 : return map->mappings[i].mapfilenumber;
184 : : }
185 : : }
186 : : else
187 : : {
5180 tgl@sss.pgh.pa.us 188 : 257359 : map = &active_local_updates;
189 [ + + ]: 258896 : for (i = 0; i < map->num_mappings; i++)
190 : : {
191 [ + + ]: 2452 : if (relationId == map->mappings[i].mapoid)
648 rhaas@postgresql.org 192 : 915 : return map->mappings[i].mapfilenumber;
193 : : }
5180 tgl@sss.pgh.pa.us 194 : 256444 : map = &local_map;
195 [ + - ]: 1908287 : for (i = 0; i < map->num_mappings; i++)
196 : : {
197 [ + + ]: 1908287 : if (relationId == map->mappings[i].mapoid)
648 rhaas@postgresql.org 198 : 256444 : return map->mappings[i].mapfilenumber;
199 : : }
200 : : }
201 : :
648 rhaas@postgresql.org 202 :UBC 0 : return InvalidRelFileNumber;
203 : : }
204 : :
205 : : /*
206 : : * RelationMapFilenumberToOid
207 : : *
208 : : * Do the reverse of the normal direction of mapping done in
209 : : * RelationMapOidToFilenumber.
210 : : *
211 : : * This is not supposed to be used during normal running but rather for
212 : : * information purposes when looking at the filesystem or xlog.
213 : : *
214 : : * Returns InvalidOid if the OID is not known; this can easily happen if the
215 : : * relfilenumber doesn't pertain to a mapped relation.
216 : : */
217 : : Oid
648 rhaas@postgresql.org 218 :CBC 531 : RelationMapFilenumberToOid(RelFileNumber filenumber, bool shared)
219 : : {
220 : : const RelMapFile *map;
221 : : int32 i;
222 : :
223 : : /* If there are active updates, believe those over the main maps */
3919 224 [ + + ]: 531 : if (shared)
225 : : {
226 : 159 : map = &active_shared_updates;
227 [ - + ]: 159 : for (i = 0; i < map->num_mappings; i++)
228 : : {
648 rhaas@postgresql.org 229 [ # # ]:UBC 0 : if (filenumber == map->mappings[i].mapfilenumber)
3919 230 : 0 : return map->mappings[i].mapoid;
231 : : }
3919 rhaas@postgresql.org 232 :CBC 159 : map = &shared_map;
233 [ + - ]: 4030 : for (i = 0; i < map->num_mappings; i++)
234 : : {
648 235 [ + + ]: 4030 : if (filenumber == map->mappings[i].mapfilenumber)
3919 236 : 159 : return map->mappings[i].mapoid;
237 : : }
238 : : }
239 : : else
240 : : {
241 : 372 : map = &active_local_updates;
242 [ - + ]: 372 : for (i = 0; i < map->num_mappings; i++)
243 : : {
648 rhaas@postgresql.org 244 [ # # ]:UBC 0 : if (filenumber == map->mappings[i].mapfilenumber)
3919 245 : 0 : return map->mappings[i].mapoid;
246 : : }
3919 rhaas@postgresql.org 247 :CBC 372 : map = &local_map;
248 [ + + ]: 2025 : for (i = 0; i < map->num_mappings; i++)
249 : : {
648 250 [ + + ]: 1972 : if (filenumber == map->mappings[i].mapfilenumber)
3919 251 : 319 : return map->mappings[i].mapoid;
252 : : }
253 : : }
254 : :
255 : 53 : return InvalidOid;
256 : : }
257 : :
258 : : /*
259 : : * RelationMapOidToFilenumberForDatabase
260 : : *
261 : : * Like RelationMapOidToFilenumber, but reads the mapping from the indicated
262 : : * path instead of using the one for the current database.
263 : : */
264 : : RelFileNumber
648 265 : 3924 : RelationMapOidToFilenumberForDatabase(char *dbpath, Oid relationId)
266 : : {
267 : : RelMapFile map;
268 : : int i;
269 : :
270 : : /* Read the relmap file from the source database. */
747 271 : 3924 : read_relmap_file(&map, dbpath, false, ERROR);
272 : :
273 : : /* Iterate over the relmap entries to find the input relation OID. */
274 [ + - ]: 33572 : for (i = 0; i < map.num_mappings; i++)
275 : : {
276 [ + + ]: 33572 : if (relationId == map.mappings[i].mapoid)
648 277 : 3924 : return map.mappings[i].mapfilenumber;
278 : : }
279 : :
648 rhaas@postgresql.org 280 :UBC 0 : return InvalidRelFileNumber;
281 : : }
282 : :
283 : : /*
284 : : * RelationMapCopy
285 : : *
286 : : * Copy relmapfile from source db path to the destination db path and WAL log
287 : : * the operation. This is intended for use in creating a new relmap file
288 : : * for a database that doesn't have one yet, not for replacing an existing
289 : : * relmap file.
290 : : */
291 : : void
747 rhaas@postgresql.org 292 :CBC 218 : RelationMapCopy(Oid dbid, Oid tsid, char *srcdbpath, char *dstdbpath)
293 : : {
294 : : RelMapFile map;
295 : :
296 : : /*
297 : : * Read the relmap file from the source database.
298 : : */
299 : 218 : read_relmap_file(&map, srcdbpath, false, ERROR);
300 : :
301 : : /*
302 : : * Write the same data into the destination database's relmap file.
303 : : *
304 : : * No sinval is needed because no one can be connected to the destination
305 : : * database yet.
306 : : *
307 : : * There's no point in trying to preserve files here. The new database
308 : : * isn't usable yet anyway, and won't ever be if we can't install a relmap
309 : : * file.
310 : : */
73 noah@leadboat.com 311 : 218 : LWLockAcquire(RelationMappingLock, LW_EXCLUSIVE);
747 rhaas@postgresql.org 312 : 218 : write_relmap_file(&map, true, false, false, dbid, tsid, dstdbpath);
73 noah@leadboat.com 313 : 218 : LWLockRelease(RelationMappingLock);
747 rhaas@postgresql.org 314 : 218 : }
315 : :
316 : : /*
317 : : * RelationMapUpdateMap
318 : : *
319 : : * Install a new relfilenumber mapping for the specified relation.
320 : : *
321 : : * If immediate is true (or we're bootstrapping), the mapping is activated
322 : : * immediately. Otherwise it is made pending until CommandCounterIncrement.
323 : : */
324 : : void
648 325 : 3437 : RelationMapUpdateMap(Oid relationId, RelFileNumber fileNumber, bool shared,
326 : : bool immediate)
327 : : {
328 : : RelMapFile *map;
329 : :
5180 tgl@sss.pgh.pa.us 330 [ + + ]: 3437 : if (IsBootstrapProcessingMode())
331 : : {
332 : : /*
333 : : * In bootstrap mode, the mapping gets installed in permanent map.
334 : : */
335 [ + + ]: 2769 : if (shared)
336 : 1950 : map = &shared_map;
337 : : else
338 : 819 : map = &local_map;
339 : : }
340 : : else
341 : : {
342 : : /*
343 : : * We don't currently support map changes within subtransactions, or
344 : : * when in parallel mode. This could be done with more bookkeeping
345 : : * infrastructure, but it doesn't presently seem worth it.
346 : : */
347 [ - + ]: 668 : if (GetCurrentTransactionNestLevel() > 1)
5180 tgl@sss.pgh.pa.us 348 [ # # ]:UBC 0 : elog(ERROR, "cannot change relation mapping within subtransaction");
349 : :
2074 pg@bowt.ie 350 [ - + ]:CBC 668 : if (IsInParallelMode())
2074 pg@bowt.ie 351 [ # # ]:UBC 0 : elog(ERROR, "cannot change relation mapping in parallel mode");
352 : :
5180 tgl@sss.pgh.pa.us 353 [ + + ]:CBC 668 : if (immediate)
354 : : {
355 : : /* Make it active, but only locally */
356 [ - + ]: 81 : if (shared)
5180 tgl@sss.pgh.pa.us 357 :UBC 0 : map = &active_shared_updates;
358 : : else
5180 tgl@sss.pgh.pa.us 359 :CBC 81 : map = &active_local_updates;
360 : : }
361 : : else
362 : : {
363 : : /* Make it pending */
364 [ + + ]: 587 : if (shared)
365 : 332 : map = &pending_shared_updates;
366 : : else
367 : 255 : map = &pending_local_updates;
368 : : }
369 : : }
648 rhaas@postgresql.org 370 : 3437 : apply_map_update(map, relationId, fileNumber, true);
5180 tgl@sss.pgh.pa.us 371 : 3437 : }
372 : :
373 : : /*
374 : : * apply_map_update
375 : : *
376 : : * Insert a new mapping into the given map variable, replacing any existing
377 : : * mapping for the same relation.
378 : : *
379 : : * In some cases the caller knows there must be an existing mapping; pass
380 : : * add_okay = false to draw an error if not.
381 : : */
382 : : static void
648 rhaas@postgresql.org 383 : 4508 : apply_map_update(RelMapFile *map, Oid relationId, RelFileNumber fileNumber,
384 : : bool add_okay)
385 : : {
386 : : int32 i;
387 : :
388 : : /* Replace any existing mapping */
5180 tgl@sss.pgh.pa.us 389 [ + + ]: 70407 : for (i = 0; i < map->num_mappings; i++)
390 : : {
391 [ + + ]: 66632 : if (relationId == map->mappings[i].mapoid)
392 : : {
648 rhaas@postgresql.org 393 : 733 : map->mappings[i].mapfilenumber = fileNumber;
5180 tgl@sss.pgh.pa.us 394 : 733 : return;
395 : : }
396 : : }
397 : :
398 : : /* Nope, need to add a new mapping */
399 [ - + ]: 3775 : if (!add_okay)
5180 tgl@sss.pgh.pa.us 400 [ # # ]:UBC 0 : elog(ERROR, "attempt to apply a mapping to unmapped relation %u",
401 : : relationId);
5180 tgl@sss.pgh.pa.us 402 [ - + ]:CBC 3775 : if (map->num_mappings >= MAX_MAPPINGS)
5180 tgl@sss.pgh.pa.us 403 [ # # ]:UBC 0 : elog(ERROR, "ran out of space in relation map");
5180 tgl@sss.pgh.pa.us 404 :CBC 3775 : map->mappings[map->num_mappings].mapoid = relationId;
648 rhaas@postgresql.org 405 : 3775 : map->mappings[map->num_mappings].mapfilenumber = fileNumber;
5180 tgl@sss.pgh.pa.us 406 : 3775 : map->num_mappings++;
407 : : }
408 : :
409 : : /*
410 : : * merge_map_updates
411 : : *
412 : : * Merge all the updates in the given pending-update map into the target map.
413 : : * This is just a bulk form of apply_map_update.
414 : : */
415 : : static void
416 : 637 : merge_map_updates(RelMapFile *map, const RelMapFile *updates, bool add_okay)
417 : : {
418 : : int32 i;
419 : :
420 [ + + ]: 1708 : for (i = 0; i < updates->num_mappings; i++)
421 : : {
422 : 1071 : apply_map_update(map,
423 : 1071 : updates->mappings[i].mapoid,
648 rhaas@postgresql.org 424 : 1071 : updates->mappings[i].mapfilenumber,
425 : : add_okay);
426 : : }
5180 tgl@sss.pgh.pa.us 427 : 637 : }
428 : :
429 : : /*
430 : : * RelationMapRemoveMapping
431 : : *
432 : : * Remove a relation's entry in the map. This is only allowed for "active"
433 : : * (but not committed) local mappings. We need it so we can back out the
434 : : * entry for the transient target file when doing VACUUM FULL/CLUSTER on
435 : : * a mapped relation.
436 : : */
437 : : void
438 : 81 : RelationMapRemoveMapping(Oid relationId)
439 : : {
440 : 81 : RelMapFile *map = &active_local_updates;
441 : : int32 i;
442 : :
443 [ + - ]: 127 : for (i = 0; i < map->num_mappings; i++)
444 : : {
445 [ + + ]: 127 : if (relationId == map->mappings[i].mapoid)
446 : : {
447 : : /* Found it, collapse it out */
448 : 81 : map->mappings[i] = map->mappings[map->num_mappings - 1];
449 : 81 : map->num_mappings--;
450 : 81 : return;
451 : : }
452 : : }
5180 tgl@sss.pgh.pa.us 453 [ # # ]:UBC 0 : elog(ERROR, "could not find temporary mapping for relation %u",
454 : : relationId);
455 : : }
456 : :
457 : : /*
458 : : * RelationMapInvalidate
459 : : *
460 : : * This routine is invoked for SI cache flush messages. We must re-read
461 : : * the indicated map file. However, we might receive a SI message in a
462 : : * process that hasn't yet, and might never, load the mapping files;
463 : : * for example the autovacuum launcher, which *must not* try to read
464 : : * a local map since it is attached to no particular database.
465 : : * So, re-read only if the map is valid now.
466 : : */
467 : : void
5180 tgl@sss.pgh.pa.us 468 :CBC 367 : RelationMapInvalidate(bool shared)
469 : : {
470 [ + + ]: 367 : if (shared)
471 : : {
472 [ + - ]: 296 : if (shared_map.magic == RELMAPPER_FILEMAGIC)
1025 heikki.linnakangas@i 473 : 296 : load_relmap_file(true, false);
474 : : }
475 : : else
476 : : {
5180 tgl@sss.pgh.pa.us 477 [ + - ]: 71 : if (local_map.magic == RELMAPPER_FILEMAGIC)
1025 heikki.linnakangas@i 478 : 71 : load_relmap_file(false, false);
479 : : }
5180 tgl@sss.pgh.pa.us 480 : 367 : }
481 : :
482 : : /*
483 : : * RelationMapInvalidateAll
484 : : *
485 : : * Reload all map files. This is used to recover from SI message buffer
486 : : * overflow: we can't be sure if we missed an inval message.
487 : : * Again, reload only currently-valid maps.
488 : : */
489 : : void
490 : 2068 : RelationMapInvalidateAll(void)
491 : : {
492 [ + - ]: 2068 : if (shared_map.magic == RELMAPPER_FILEMAGIC)
1025 heikki.linnakangas@i 493 : 2068 : load_relmap_file(true, false);
5180 tgl@sss.pgh.pa.us 494 [ + + ]: 2068 : if (local_map.magic == RELMAPPER_FILEMAGIC)
1025 heikki.linnakangas@i 495 : 2030 : load_relmap_file(false, false);
5180 tgl@sss.pgh.pa.us 496 : 2068 : }
497 : :
498 : : /*
499 : : * AtCCI_RelationMap
500 : : *
501 : : * Activate any "pending" relation map updates at CommandCounterIncrement time.
502 : : */
503 : : void
504 : 517351 : AtCCI_RelationMap(void)
505 : : {
506 [ + + ]: 517351 : if (pending_shared_updates.num_mappings != 0)
507 : : {
508 : 300 : merge_map_updates(&active_shared_updates,
509 : : &pending_shared_updates,
510 : : true);
511 : 300 : pending_shared_updates.num_mappings = 0;
512 : : }
513 [ + + ]: 517351 : if (pending_local_updates.num_mappings != 0)
514 : : {
515 : 180 : merge_map_updates(&active_local_updates,
516 : : &pending_local_updates,
517 : : true);
518 : 180 : pending_local_updates.num_mappings = 0;
519 : : }
520 : 517351 : }
521 : :
522 : : /*
523 : : * AtEOXact_RelationMap
524 : : *
525 : : * Handle relation mapping at main-transaction commit or abort.
526 : : *
527 : : * During commit, this must be called as late as possible before the actual
528 : : * transaction commit, so as to minimize the window where the transaction
529 : : * could still roll back after committing map changes. Although nothing
530 : : * critically bad happens in such a case, we still would prefer that it
531 : : * not happen, since we'd possibly be losing useful updates to the relations'
532 : : * pg_class row(s).
533 : : *
534 : : * During abort, we just have to throw away any pending map changes.
535 : : * Normal post-abort cleanup will take care of fixing relcache entries.
536 : : * Parallel worker commit/abort is handled by resetting active mappings
537 : : * that may have been received from the leader process. (There should be
538 : : * no pending updates in parallel workers.)
539 : : */
540 : : void
2074 pg@bowt.ie 541 : 432701 : AtEOXact_RelationMap(bool isCommit, bool isParallelWorker)
542 : : {
543 [ + + + + ]: 432701 : if (isCommit && !isParallelWorker)
544 : : {
545 : : /*
546 : : * We should not get here with any "pending" updates. (We could
547 : : * logically choose to treat such as committed, but in the current
548 : : * code this should never happen.)
549 : : */
5180 tgl@sss.pgh.pa.us 550 [ - + ]: 408552 : Assert(pending_shared_updates.num_mappings == 0);
551 [ - + ]: 408552 : Assert(pending_local_updates.num_mappings == 0);
552 : :
553 : : /*
554 : : * Write any active updates to the actual map files, then reset them.
555 : : */
556 [ + + ]: 408552 : if (active_shared_updates.num_mappings != 0)
557 : : {
558 : 107 : perform_relmap_update(true, &active_shared_updates);
559 : 107 : active_shared_updates.num_mappings = 0;
560 : : }
561 [ + + ]: 408552 : if (active_local_updates.num_mappings != 0)
562 : : {
563 : 50 : perform_relmap_update(false, &active_local_updates);
564 : 50 : active_local_updates.num_mappings = 0;
565 : : }
566 : : }
567 : : else
568 : : {
569 : : /* Abort or parallel worker --- drop all local and pending updates */
2074 pg@bowt.ie 570 [ + + - + ]: 24149 : Assert(!isParallelWorker || pending_shared_updates.num_mappings == 0);
571 [ + + - + ]: 24149 : Assert(!isParallelWorker || pending_local_updates.num_mappings == 0);
572 : :
5180 tgl@sss.pgh.pa.us 573 : 24149 : active_shared_updates.num_mappings = 0;
574 : 24149 : active_local_updates.num_mappings = 0;
575 : 24149 : pending_shared_updates.num_mappings = 0;
576 : 24149 : pending_local_updates.num_mappings = 0;
577 : : }
578 : 432701 : }
579 : :
580 : : /*
581 : : * AtPrepare_RelationMap
582 : : *
583 : : * Handle relation mapping at PREPARE.
584 : : *
585 : : * Currently, we don't support preparing any transaction that changes the map.
586 : : */
587 : : void
588 : 396 : AtPrepare_RelationMap(void)
589 : : {
590 [ + - ]: 396 : if (active_shared_updates.num_mappings != 0 ||
591 [ + - ]: 396 : active_local_updates.num_mappings != 0 ||
592 [ + - ]: 396 : pending_shared_updates.num_mappings != 0 ||
593 [ - + ]: 396 : pending_local_updates.num_mappings != 0)
5180 tgl@sss.pgh.pa.us 594 [ # # ]:UBC 0 : ereport(ERROR,
595 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
596 : : errmsg("cannot PREPARE a transaction that modified relation mapping")));
5180 tgl@sss.pgh.pa.us 597 :CBC 396 : }
598 : :
599 : : /*
600 : : * CheckPointRelationMap
601 : : *
602 : : * This is called during a checkpoint. It must ensure that any relation map
603 : : * updates that were WAL-logged before the start of the checkpoint are
604 : : * securely flushed to disk and will not need to be replayed later. This
605 : : * seems unlikely to be a performance-critical issue, so we use a simple
606 : : * method: we just take and release the RelationMappingLock. This ensures
607 : : * that any already-logged map update is complete, because write_relmap_file
608 : : * will fsync the map file before the lock is released.
609 : : */
610 : : void
611 : 1153 : CheckPointRelationMap(void)
612 : : {
613 : 1153 : LWLockAcquire(RelationMappingLock, LW_SHARED);
614 : 1153 : LWLockRelease(RelationMappingLock);
615 : 1153 : }
616 : :
617 : : /*
618 : : * RelationMapFinishBootstrap
619 : : *
620 : : * Write out the initial relation mapping files at the completion of
621 : : * bootstrap. All the mapped files should have been made known to us
622 : : * via RelationMapUpdateMap calls.
623 : : */
624 : : void
625 : 39 : RelationMapFinishBootstrap(void)
626 : : {
627 [ - + ]: 39 : Assert(IsBootstrapProcessingMode());
628 : :
629 : : /* Shouldn't be anything "pending" ... */
630 [ - + ]: 39 : Assert(active_shared_updates.num_mappings == 0);
631 [ - + ]: 39 : Assert(active_local_updates.num_mappings == 0);
632 [ - + ]: 39 : Assert(pending_shared_updates.num_mappings == 0);
633 [ - + ]: 39 : Assert(pending_local_updates.num_mappings == 0);
634 : :
635 : : /* Write the files; no WAL or sinval needed */
73 noah@leadboat.com 636 : 39 : LWLockAcquire(RelationMappingLock, LW_EXCLUSIVE);
759 rhaas@postgresql.org 637 : 39 : write_relmap_file(&shared_map, false, false, false,
638 : : InvalidOid, GLOBALTABLESPACE_OID, "global");
639 : 39 : write_relmap_file(&local_map, false, false, false,
640 : : MyDatabaseId, MyDatabaseTableSpace, DatabasePath);
73 noah@leadboat.com 641 : 39 : LWLockRelease(RelationMappingLock);
5180 tgl@sss.pgh.pa.us 642 : 39 : }
643 : :
644 : : /*
645 : : * RelationMapInitialize
646 : : *
647 : : * This initializes the mapper module at process startup. We can't access the
648 : : * database yet, so just make sure the maps are empty.
649 : : */
650 : : void
651 : 16409 : RelationMapInitialize(void)
652 : : {
653 : : /* The static variables should initialize to zeroes, but let's be sure */
654 : 16409 : shared_map.magic = 0; /* mark it not loaded */
655 : 16409 : local_map.magic = 0;
656 : 16409 : shared_map.num_mappings = 0;
657 : 16409 : local_map.num_mappings = 0;
658 : 16409 : active_shared_updates.num_mappings = 0;
659 : 16409 : active_local_updates.num_mappings = 0;
660 : 16409 : pending_shared_updates.num_mappings = 0;
661 : 16409 : pending_local_updates.num_mappings = 0;
662 : 16409 : }
663 : :
664 : : /*
665 : : * RelationMapInitializePhase2
666 : : *
667 : : * This is called to prepare for access to pg_database during startup.
668 : : * We should be able to read the shared map file now.
669 : : */
670 : : void
671 : 16409 : RelationMapInitializePhase2(void)
672 : : {
673 : : /*
674 : : * In bootstrap mode, the map file isn't there yet, so do nothing.
675 : : */
676 [ + + ]: 16409 : if (IsBootstrapProcessingMode())
677 : 39 : return;
678 : :
679 : : /*
680 : : * Load the shared map file, die on error.
681 : : */
1025 heikki.linnakangas@i 682 : 16370 : load_relmap_file(true, false);
683 : : }
684 : :
685 : : /*
686 : : * RelationMapInitializePhase3
687 : : *
688 : : * This is called as soon as we have determined MyDatabaseId and set up
689 : : * DatabasePath. At this point we should be able to read the local map file.
690 : : */
691 : : void
5180 tgl@sss.pgh.pa.us 692 : 13259 : RelationMapInitializePhase3(void)
693 : : {
694 : : /*
695 : : * In bootstrap mode, the map file isn't there yet, so do nothing.
696 : : */
697 [ + + ]: 13259 : if (IsBootstrapProcessingMode())
698 : 39 : return;
699 : :
700 : : /*
701 : : * Load the local map file, die on error.
702 : : */
1025 heikki.linnakangas@i 703 : 13220 : load_relmap_file(false, false);
704 : : }
705 : :
706 : : /*
707 : : * EstimateRelationMapSpace
708 : : *
709 : : * Estimate space needed to pass active shared and local relmaps to parallel
710 : : * workers.
711 : : */
712 : : Size
2074 pg@bowt.ie 713 : 828 : EstimateRelationMapSpace(void)
714 : : {
715 : 828 : return sizeof(SerializedActiveRelMaps);
716 : : }
717 : :
718 : : /*
719 : : * SerializeRelationMap
720 : : *
721 : : * Serialize active shared and local relmap state for parallel workers.
722 : : */
723 : : void
724 : 414 : SerializeRelationMap(Size maxSize, char *startAddress)
725 : : {
726 : : SerializedActiveRelMaps *relmaps;
727 : :
728 [ - + ]: 414 : Assert(maxSize >= EstimateRelationMapSpace());
729 : :
730 : 414 : relmaps = (SerializedActiveRelMaps *) startAddress;
731 : 414 : relmaps->active_shared_updates = active_shared_updates;
732 : 414 : relmaps->active_local_updates = active_local_updates;
733 : 414 : }
734 : :
735 : : /*
736 : : * RestoreRelationMap
737 : : *
738 : : * Restore active shared and local relmap state within a parallel worker.
739 : : */
740 : : void
741 : 1322 : RestoreRelationMap(char *startAddress)
742 : : {
743 : : SerializedActiveRelMaps *relmaps;
744 : :
745 [ + - ]: 1322 : if (active_shared_updates.num_mappings != 0 ||
746 [ + - ]: 1322 : active_local_updates.num_mappings != 0 ||
747 [ + - ]: 1322 : pending_shared_updates.num_mappings != 0 ||
748 [ - + ]: 1322 : pending_local_updates.num_mappings != 0)
2074 pg@bowt.ie 749 [ # # ]:UBC 0 : elog(ERROR, "parallel worker has existing mappings");
750 : :
2074 pg@bowt.ie 751 :CBC 1322 : relmaps = (SerializedActiveRelMaps *) startAddress;
752 : 1322 : active_shared_updates = relmaps->active_shared_updates;
753 : 1322 : active_local_updates = relmaps->active_local_updates;
754 : 1322 : }
755 : :
756 : : /*
757 : : * load_relmap_file -- load the shared or local map file
758 : : *
759 : : * Because these files are essential for access to core system catalogs,
760 : : * failure to load either of them is a fatal error.
761 : : *
762 : : * Note that the local case requires DatabasePath to be set up.
763 : : */
764 : : static void
1025 heikki.linnakangas@i 765 : 34212 : load_relmap_file(bool shared, bool lock_held)
766 : : {
759 rhaas@postgresql.org 767 [ + + ]: 34212 : if (shared)
768 : 18841 : read_relmap_file(&shared_map, "global", lock_held, FATAL);
769 : : else
770 : 15371 : read_relmap_file(&local_map, DatabasePath, lock_held, FATAL);
771 : 34212 : }
772 : :
773 : : /*
774 : : * read_relmap_file -- load data from any relation mapper file
775 : : *
776 : : * dbpath must be the relevant database path, or "global" for shared relations.
777 : : *
778 : : * RelationMappingLock will be acquired released unless lock_held = true.
779 : : *
780 : : * Errors will be reported at the indicated elevel, which should be at least
781 : : * ERROR.
782 : : */
783 : : static void
784 : 38354 : read_relmap_file(RelMapFile *map, char *dbpath, bool lock_held, int elevel)
785 : : {
786 : : char mapfilename[MAXPGPATH];
787 : : pg_crc32c crc;
788 : : int fd;
789 : : int r;
790 : :
791 [ - + ]: 38354 : Assert(elevel >= ERROR);
792 : :
793 : : /*
794 : : * Grab the lock to prevent the file from being updated while we read it,
795 : : * unless the caller is already holding the lock. If the file is updated
796 : : * shortly after we look, the sinval signaling mechanism will make us
797 : : * re-read it before we are able to access any relation that's affected by
798 : : * the change.
799 : : */
1025 heikki.linnakangas@i 800 [ + + ]: 38354 : if (!lock_held)
801 : 38197 : LWLockAcquire(RelationMappingLock, LW_SHARED);
802 : :
803 : : /*
804 : : * Open the target file.
805 : : *
806 : : * Because Windows isn't happy about the idea of renaming over a file that
807 : : * someone has open, we only open this file after acquiring the lock, and
808 : : * for the same reason, we close it before releasing the lock. That way,
809 : : * by the time write_relmap_file() acquires an exclusive lock, no one else
810 : : * will have it open.
811 : : */
627 rhaas@postgresql.org 812 : 38354 : snprintf(mapfilename, sizeof(mapfilename), "%s/%s", dbpath,
813 : : RELMAPPER_FILENAME);
814 : 38354 : fd = OpenTransientFile(mapfilename, O_RDONLY | PG_BINARY);
815 [ - + ]: 38354 : if (fd < 0)
627 rhaas@postgresql.org 816 [ # # ]:UBC 0 : ereport(elevel,
817 : : (errcode_for_file_access(),
818 : : errmsg("could not open file \"%s\": %m",
819 : : mapfilename)));
820 : :
821 : : /* Now read the data. */
2584 rhaas@postgresql.org 822 :CBC 38354 : pgstat_report_wait_start(WAIT_EVENT_RELATION_MAP_READ);
2097 michael@paquier.xyz 823 : 38354 : r = read(fd, map, sizeof(RelMapFile));
824 [ - + ]: 38354 : if (r != sizeof(RelMapFile))
825 : : {
2097 michael@paquier.xyz 826 [ # # ]:UBC 0 : if (r < 0)
759 rhaas@postgresql.org 827 [ # # ]: 0 : ereport(elevel,
828 : : (errcode_for_file_access(),
829 : : errmsg("could not read file \"%s\": %m", mapfilename)));
830 : : else
831 [ # # ]: 0 : ereport(elevel,
832 : : (errcode(ERRCODE_DATA_CORRUPTED),
833 : : errmsg("could not read file \"%s\": read %d of %zu",
834 : : mapfilename, r, sizeof(RelMapFile))));
835 : : }
2584 rhaas@postgresql.org 836 :CBC 38354 : pgstat_report_wait_end();
837 : :
1744 peter@eisentraut.org 838 [ - + ]: 38354 : if (CloseTransientFile(fd) != 0)
759 rhaas@postgresql.org 839 [ # # ]:UBC 0 : ereport(elevel,
840 : : (errcode_for_file_access(),
841 : : errmsg("could not close file \"%s\": %m",
842 : : mapfilename)));
843 : :
627 rhaas@postgresql.org 844 [ + + ]:CBC 38354 : if (!lock_held)
845 : 38197 : LWLockRelease(RelationMappingLock);
846 : :
847 : : /* check for correct magic number, etc */
5180 tgl@sss.pgh.pa.us 848 [ + - ]: 38354 : if (map->magic != RELMAPPER_FILEMAGIC ||
849 [ + - ]: 38354 : map->num_mappings < 0 ||
850 [ - + ]: 38354 : map->num_mappings > MAX_MAPPINGS)
759 rhaas@postgresql.org 851 [ # # ]:UBC 0 : ereport(elevel,
852 : : (errmsg("relation mapping file \"%s\" contains invalid data",
853 : : mapfilename)));
854 : :
855 : : /* verify the CRC */
3449 heikki.linnakangas@i 856 :CBC 38354 : INIT_CRC32C(crc);
857 : 38354 : COMP_CRC32C(crc, (char *) map, offsetof(RelMapFile, crc));
858 : 38354 : FIN_CRC32C(crc);
859 : :
860 [ - + ]: 38354 : if (!EQ_CRC32C(crc, map->crc))
759 rhaas@postgresql.org 861 [ # # ]:UBC 0 : ereport(elevel,
862 : : (errmsg("relation mapping file \"%s\" contains incorrect checksum",
863 : : mapfilename)));
5180 tgl@sss.pgh.pa.us 864 :CBC 38354 : }
865 : :
866 : : /*
867 : : * Write out a new shared or local map file with the given contents.
868 : : *
869 : : * The magic number and CRC are automatically updated in *newmap. On
870 : : * success, we copy the data to the appropriate permanent static variable.
871 : : *
872 : : * If write_wal is true then an appropriate WAL message is emitted.
873 : : * (It will be false for bootstrap and WAL replay cases.)
874 : : *
875 : : * If send_sinval is true then a SI invalidation message is sent.
876 : : * (This should be true except in bootstrap case.)
877 : : *
878 : : * If preserve_files is true then the storage manager is warned not to
879 : : * delete the files listed in the map.
880 : : *
881 : : * Because this may be called during WAL replay when MyDatabaseId,
882 : : * DatabasePath, etc aren't valid, we require the caller to pass in suitable
883 : : * values. Pass dbpath as "global" for the shared map.
884 : : *
885 : : * The caller is also responsible for being sure no concurrent map update
886 : : * could be happening.
887 : : */
888 : : static void
759 rhaas@postgresql.org 889 : 491 : write_relmap_file(RelMapFile *newmap, bool write_wal, bool send_sinval,
890 : : bool preserve_files, Oid dbid, Oid tsid, const char *dbpath)
891 : : {
892 : : int fd;
893 : : char mapfilename[MAXPGPATH];
894 : : char maptempfilename[MAXPGPATH];
895 : :
896 : : /*
897 : : * Even without concurrent use of this map, CheckPointRelationMap() relies
898 : : * on this locking. Without it, a restore of a base backup taken after
899 : : * this function's XLogInsert() and before its durable_rename() would not
900 : : * have the changes. wal_level=minimal doesn't need the lock, but this
901 : : * isn't performance-critical enough for such a micro-optimization.
902 : : */
73 noah@leadboat.com 903 [ - + ]: 491 : Assert(LWLockHeldByMeInMode(RelationMappingLock, LW_EXCLUSIVE));
904 : :
905 : : /*
906 : : * Fill in the overhead fields and update CRC.
907 : : */
5180 tgl@sss.pgh.pa.us 908 : 491 : newmap->magic = RELMAPPER_FILEMAGIC;
909 [ + - - + ]: 491 : if (newmap->num_mappings < 0 || newmap->num_mappings > MAX_MAPPINGS)
5180 tgl@sss.pgh.pa.us 910 [ # # ]:UBC 0 : elog(ERROR, "attempt to write bogus relation mapping");
911 : :
3449 heikki.linnakangas@i 912 :CBC 491 : INIT_CRC32C(newmap->crc);
913 : 491 : COMP_CRC32C(newmap->crc, (char *) newmap, offsetof(RelMapFile, crc));
914 : 491 : FIN_CRC32C(newmap->crc);
915 : :
916 : : /*
917 : : * Construct filenames -- a temporary file that we'll create to write the
918 : : * data initially, and then the permanent name to which we will rename it.
919 : : */
759 rhaas@postgresql.org 920 : 491 : snprintf(mapfilename, sizeof(mapfilename), "%s/%s",
921 : : dbpath, RELMAPPER_FILENAME);
628 922 : 491 : snprintf(maptempfilename, sizeof(maptempfilename), "%s/%s",
923 : : dbpath, RELMAPPER_TEMP_FILENAME);
924 : :
925 : : /*
926 : : * Open a temporary file. If a file already exists with this name, it must
927 : : * be left over from a previous crash, so we can overwrite it. Concurrent
928 : : * calls to this function are not allowed.
929 : : */
930 : 491 : fd = OpenTransientFile(maptempfilename,
931 : : O_WRONLY | O_CREAT | O_TRUNC | PG_BINARY);
5180 tgl@sss.pgh.pa.us 932 [ - + ]: 491 : if (fd < 0)
5180 tgl@sss.pgh.pa.us 933 [ # # ]:UBC 0 : ereport(ERROR,
934 : : (errcode_for_file_access(),
935 : : errmsg("could not open file \"%s\": %m",
936 : : maptempfilename)));
937 : :
938 : : /* Write new data to the file. */
628 rhaas@postgresql.org 939 :CBC 491 : pgstat_report_wait_start(WAIT_EVENT_RELATION_MAP_WRITE);
940 [ - + ]: 491 : if (write(fd, newmap, sizeof(RelMapFile)) != sizeof(RelMapFile))
941 : : {
942 : : /* if write didn't set errno, assume problem is no disk space */
628 rhaas@postgresql.org 943 [ # # ]:UBC 0 : if (errno == 0)
944 : 0 : errno = ENOSPC;
945 [ # # ]: 0 : ereport(ERROR,
946 : : (errcode_for_file_access(),
947 : : errmsg("could not write file \"%s\": %m",
948 : : maptempfilename)));
949 : : }
628 rhaas@postgresql.org 950 :CBC 491 : pgstat_report_wait_end();
951 : :
952 : : /* And close the file. */
953 [ - + ]: 491 : if (CloseTransientFile(fd) != 0)
628 rhaas@postgresql.org 954 [ # # ]:UBC 0 : ereport(ERROR,
955 : : (errcode_for_file_access(),
956 : : errmsg("could not close file \"%s\": %m",
957 : : maptempfilename)));
958 : :
5180 tgl@sss.pgh.pa.us 959 [ + + ]:CBC 491 : if (write_wal)
960 : : {
961 : : xl_relmap_update xlrec;
962 : : XLogRecPtr lsn;
963 : :
964 : : /* now errors are fatal ... */
965 : 375 : START_CRIT_SECTION();
966 : :
967 : 375 : xlrec.dbid = dbid;
968 : 375 : xlrec.tsid = tsid;
969 : 375 : xlrec.nbytes = sizeof(RelMapFile);
970 : :
3433 heikki.linnakangas@i 971 : 375 : XLogBeginInsert();
972 : 375 : XLogRegisterData((char *) (&xlrec), MinSizeOfRelmapUpdate);
973 : 375 : XLogRegisterData((char *) newmap, sizeof(RelMapFile));
974 : :
975 : 375 : lsn = XLogInsert(RM_RELMAP_ID, XLOG_RELMAP_UPDATE);
976 : :
977 : : /* As always, WAL must hit the disk before the data update does */
5180 tgl@sss.pgh.pa.us 978 : 375 : XLogFlush(lsn);
979 : : }
980 : :
981 : : /*
982 : : * durable_rename() does all the hard work of making sure that we rename
983 : : * the temporary file into place in a crash-safe manner.
984 : : *
985 : : * NB: Although we instruct durable_rename() to use ERROR, we will often
986 : : * be in a critical section at this point; if so, ERROR will become PANIC.
987 : : */
628 rhaas@postgresql.org 988 : 491 : pgstat_report_wait_start(WAIT_EVENT_RELATION_MAP_REPLACE);
989 : 491 : durable_rename(maptempfilename, mapfilename, ERROR);
2584 990 : 491 : pgstat_report_wait_end();
991 : :
992 : : /*
993 : : * Now that the file is safely on disk, send sinval message to let other
994 : : * backends know to re-read it. We must do this inside the critical
995 : : * section: if for some reason we fail to send the message, we have to
996 : : * force a database-wide PANIC. Otherwise other backends might continue
997 : : * execution with stale mapping information, which would be catastrophic
998 : : * as soon as others began to use the now-committed data.
999 : : */
5180 tgl@sss.pgh.pa.us 1000 [ + + ]: 491 : if (send_sinval)
1001 : 195 : CacheInvalidateRelmap(dbid);
1002 : :
1003 : : /*
1004 : : * Make sure that the files listed in the map are not deleted if the outer
1005 : : * transaction aborts. This had better be within the critical section
1006 : : * too: it's not likely to fail, but if it did, we'd arrive at transaction
1007 : : * abort with the files still vulnerable. PANICing will leave things in a
1008 : : * good state on-disk.
1009 : : *
1010 : : * Note: we're cheating a little bit here by assuming that mapped files
1011 : : * are either in pg_global or the database's default tablespace.
1012 : : */
1013 [ + + ]: 491 : if (preserve_files)
1014 : : {
1015 : : int32 i;
1016 : :
1017 [ + + ]: 6357 : for (i = 0; i < newmap->num_mappings; i++)
1018 : : {
1019 : : RelFileLocator rlocator;
1020 : :
648 rhaas@postgresql.org 1021 : 6200 : rlocator.spcOid = tsid;
1022 : 6200 : rlocator.dbOid = dbid;
1023 : 6200 : rlocator.relNumber = newmap->mappings[i].mapfilenumber;
1024 : 6200 : RelationPreserveStorage(rlocator, false);
1025 : : }
1026 : : }
1027 : :
1028 : : /* Critical section done */
5180 tgl@sss.pgh.pa.us 1029 [ + + ]: 491 : if (write_wal)
1030 [ - + ]: 375 : END_CRIT_SECTION();
1031 : 491 : }
1032 : :
1033 : : /*
1034 : : * Merge the specified updates into the appropriate "real" map,
1035 : : * and write out the changes. This function must be used for committing
1036 : : * updates during normal multiuser operation.
1037 : : */
1038 : : static void
1039 : 157 : perform_relmap_update(bool shared, const RelMapFile *updates)
1040 : : {
1041 : : RelMapFile newmap;
1042 : :
1043 : : /*
1044 : : * Anyone updating a relation's mapping info should take exclusive lock on
1045 : : * that rel and hold it until commit. This ensures that there will not be
1046 : : * concurrent updates on the same mapping value; but there could easily be
1047 : : * concurrent updates on different values in the same file. We cover that
1048 : : * by acquiring the RelationMappingLock, re-reading the target file to
1049 : : * ensure it's up to date, applying the updates, and writing the data
1050 : : * before releasing RelationMappingLock.
1051 : : *
1052 : : * There is only one RelationMappingLock. In principle we could try to
1053 : : * have one per mapping file, but it seems unlikely to be worth the
1054 : : * trouble.
1055 : : */
1056 : 157 : LWLockAcquire(RelationMappingLock, LW_EXCLUSIVE);
1057 : :
1058 : : /* Be certain we see any other updates just made */
1025 heikki.linnakangas@i 1059 : 157 : load_relmap_file(shared, true);
1060 : :
1061 : : /* Prepare updated data in a local variable */
5180 tgl@sss.pgh.pa.us 1062 [ + + ]: 157 : if (shared)
1063 : 107 : memcpy(&newmap, &shared_map, sizeof(RelMapFile));
1064 : : else
1065 : 50 : memcpy(&newmap, &local_map, sizeof(RelMapFile));
1066 : :
1067 : : /*
1068 : : * Apply the updates to newmap. No new mappings should appear, unless
1069 : : * somebody is adding indexes to system catalogs.
1070 : : */
4407 1071 : 157 : merge_map_updates(&newmap, updates, allowSystemTableMods);
1072 : :
1073 : : /* Write out the updated map and do other necessary tasks */
759 rhaas@postgresql.org 1074 [ + + + + : 157 : write_relmap_file(&newmap, true, true, true,
+ + ]
1075 : : (shared ? InvalidOid : MyDatabaseId),
1076 : : (shared ? GLOBALTABLESPACE_OID : MyDatabaseTableSpace),
1077 : : (shared ? "global" : DatabasePath));
1078 : :
1079 : : /*
1080 : : * We successfully wrote the updated file, so it's now safe to rely on the
1081 : : * new values in this process, too.
1082 : : */
1083 [ + + ]: 157 : if (shared)
1084 : 107 : memcpy(&shared_map, &newmap, sizeof(RelMapFile));
1085 : : else
1086 : 50 : memcpy(&local_map, &newmap, sizeof(RelMapFile));
1087 : :
1088 : : /* Now we can release the lock */
5180 tgl@sss.pgh.pa.us 1089 : 157 : LWLockRelease(RelationMappingLock);
1090 : 157 : }
1091 : :
1092 : : /*
1093 : : * RELMAP resource manager's routines
1094 : : */
1095 : : void
3433 heikki.linnakangas@i 1096 : 38 : relmap_redo(XLogReaderState *record)
1097 : : {
1098 : 38 : uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
1099 : :
1100 : : /* Backup blocks are not used in relmap records */
1101 [ - + ]: 38 : Assert(!XLogRecHasAnyBlockRefs(record));
1102 : :
5180 tgl@sss.pgh.pa.us 1103 [ + - ]: 38 : if (info == XLOG_RELMAP_UPDATE)
1104 : : {
1105 : 38 : xl_relmap_update *xlrec = (xl_relmap_update *) XLogRecGetData(record);
1106 : : RelMapFile newmap;
1107 : : char *dbpath;
1108 : :
1109 [ - + ]: 38 : if (xlrec->nbytes != sizeof(RelMapFile))
5180 tgl@sss.pgh.pa.us 1110 [ # # ]:UBC 0 : elog(PANIC, "relmap_redo: wrong size %u in relmap update record",
1111 : : xlrec->nbytes);
5180 tgl@sss.pgh.pa.us 1112 :CBC 38 : memcpy(&newmap, xlrec->data, sizeof(newmap));
1113 : :
1114 : : /* We need to construct the pathname for this database */
1115 : 38 : dbpath = GetDatabasePath(xlrec->dbid, xlrec->tsid);
1116 : :
1117 : : /*
1118 : : * Write out the new map and send sinval, but of course don't write a
1119 : : * new WAL entry. There's no surrounding transaction to tell to
1120 : : * preserve files, either.
1121 : : *
1122 : : * There shouldn't be anyone else updating relmaps during WAL replay,
1123 : : * but grab the lock to interlock against load_relmap_file().
1124 : : *
1125 : : * Note that we use the same WAL record for updating the relmap of an
1126 : : * existing database as we do for creating a new database. In the
1127 : : * latter case, taking the relmap log and sending sinval messages is
1128 : : * unnecessary, but harmless. If we wanted to avoid it, we could add a
1129 : : * flag to the WAL record to indicate which operation is being
1130 : : * performed.
1131 : : */
1025 heikki.linnakangas@i 1132 : 38 : LWLockAcquire(RelationMappingLock, LW_EXCLUSIVE);
759 rhaas@postgresql.org 1133 : 38 : write_relmap_file(&newmap, false, true, false,
1134 : : xlrec->dbid, xlrec->tsid, dbpath);
1025 heikki.linnakangas@i 1135 : 38 : LWLockRelease(RelationMappingLock);
1136 : :
5180 tgl@sss.pgh.pa.us 1137 : 38 : pfree(dbpath);
1138 : : }
1139 : : else
5180 tgl@sss.pgh.pa.us 1140 [ # # ]:UBC 0 : elog(PANIC, "relmap_redo: unknown op code %u", info);
5180 tgl@sss.pgh.pa.us 1141 :CBC 38 : }
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