Coverage Report

Created: 2026-08-13 07:12

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/src/postgres/src/backend/catalog/catalog.c
Line
Count
Source
1
/*-------------------------------------------------------------------------
2
 *
3
 * catalog.c
4
 *    routines concerned with catalog naming conventions and other
5
 *    bits of hard-wired knowledge
6
 *
7
 *
8
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
9
 * Portions Copyright (c) 1994, Regents of the University of California
10
 *
11
 *
12
 * IDENTIFICATION
13
 *    src/backend/catalog/catalog.c
14
 *
15
 *-------------------------------------------------------------------------
16
 */
17
18
#include "postgres.h"
19
20
#include <fcntl.h>
21
#include <unistd.h>
22
23
#include "access/genam.h"
24
#include "access/htup_details.h"
25
#include "access/table.h"
26
#include "access/transam.h"
27
#include "catalog/catalog.h"
28
#include "catalog/namespace.h"
29
#include "catalog/pg_auth_members.h"
30
#include "catalog/pg_authid.h"
31
#include "catalog/pg_database.h"
32
#include "catalog/pg_db_role_setting.h"
33
#include "catalog/pg_largeobject.h"
34
#include "catalog/pg_namespace.h"
35
#include "catalog/pg_parameter_acl.h"
36
#include "catalog/pg_replication_origin.h"
37
#include "catalog/pg_seclabel.h"
38
#include "catalog/pg_shdepend.h"
39
#include "catalog/pg_shdescription.h"
40
#include "catalog/pg_shseclabel.h"
41
#include "catalog/pg_subscription.h"
42
#include "catalog/pg_tablespace.h"
43
#include "catalog/pg_type.h"
44
#include "miscadmin.h"
45
#include "utils/fmgroids.h"
46
#include "utils/fmgrprotos.h"
47
#include "utils/rel.h"
48
#include "utils/snapmgr.h"
49
#include "utils/syscache.h"
50
51
/*
52
 * Parameters to determine when to emit a log message in
53
 * GetNewOidWithIndex()
54
 */
55
#define GETNEWOID_LOG_THRESHOLD 1000000
56
#define GETNEWOID_LOG_MAX_INTERVAL 128000000
57
58
/*
59
 * IsSystemRelation
60
 *    True iff the relation is either a system catalog or a toast table.
61
 *    See IsCatalogRelation for the exact definition of a system catalog.
62
 *
63
 *    We treat toast tables of user relations as "system relations" for
64
 *    protection purposes, e.g. you can't change their schemas without
65
 *    special permissions.  Therefore, most uses of this function are
66
 *    checking whether allow_system_table_mods restrictions apply.
67
 *    For other purposes, consider whether you shouldn't be using
68
 *    IsCatalogRelation instead.
69
 *
70
 *    This function does not perform any catalog accesses.
71
 *    Some callers rely on that!
72
 */
73
bool
74
IsSystemRelation(Relation relation)
75
0
{
76
0
  return IsSystemClass(RelationGetRelid(relation), relation->rd_rel);
77
0
}
78
79
/*
80
 * IsSystemClass
81
 *    Like the above, but takes a Form_pg_class as argument.
82
 *    Used when we do not want to open the relation and have to
83
 *    search pg_class directly.
84
 */
85
bool
86
IsSystemClass(Oid relid, Form_pg_class reltuple)
87
0
{
88
  /* IsCatalogRelationOid is a bit faster, so test that first */
89
0
  return (IsCatalogRelationOid(relid) ||
90
0
      IsToastClass(reltuple) ||
91
0
      IsConflictLogTableClass(reltuple));
92
0
}
93
94
/*
95
 * IsCatalogRelation
96
 *    True iff the relation is a system catalog.
97
 *
98
 *    By a system catalog, we mean one that is created during the bootstrap
99
 *    phase of initdb.  That includes not just the catalogs per se, but
100
 *    also their indexes, and TOAST tables and indexes if any.
101
 *
102
 *    This function does not perform any catalog accesses.
103
 *    Some callers rely on that!
104
 */
105
bool
106
IsCatalogRelation(Relation relation)
107
0
{
108
0
  return IsCatalogRelationOid(RelationGetRelid(relation));
109
0
}
110
111
/*
112
 * IsCatalogRelationOid
113
 *    True iff the relation identified by this OID is a system catalog.
114
 *
115
 *    By a system catalog, we mean one that is created during the bootstrap
116
 *    phase of initdb.  That includes not just the catalogs per se, but
117
 *    also their indexes, and TOAST tables and indexes if any.
118
 *
119
 *    This function does not perform any catalog accesses.
120
 *    Some callers rely on that!
121
 */
122
bool
123
IsCatalogRelationOid(Oid relid)
124
0
{
125
  /*
126
   * We consider a relation to be a system catalog if it has a pinned OID.
127
   * This includes all the defined catalogs, their indexes, and their TOAST
128
   * tables and indexes.
129
   *
130
   * This rule excludes the relations in information_schema, which are not
131
   * integral to the system and can be treated the same as user relations.
132
   * (Since it's valid to drop and recreate information_schema, any rule
133
   * that did not act this way would be wrong.)
134
   *
135
   * This test is reliable since an OID wraparound will skip this range of
136
   * OIDs; see GetNewObjectId().
137
   */
138
0
  return (relid < (Oid) FirstUnpinnedObjectId);
139
0
}
140
141
/*
142
 * IsCatalogTextUniqueIndexOid
143
 *    True iff the relation identified by this OID is a catalog UNIQUE index
144
 *    having a column of type "text".
145
 *
146
 *    The relcache must not use these indexes.  Inserting into any UNIQUE
147
 *    index compares index keys while holding BUFFER_LOCK_EXCLUSIVE.
148
 *    bttextcmp() can search the COLLOID catcache.  Depending on concurrent
149
 *    invalidation traffic, catcache can reach relcache builds.  A backend
150
 *    would self-deadlock on LWLocks if the relcache build read the
151
 *    exclusive-locked buffer.
152
 *
153
 *    To avoid being itself the cause of self-deadlock, this doesn't read
154
 *    catalogs.  Instead, it uses a hard-coded list with a supporting
155
 *    regression test.
156
 */
157
bool
158
IsCatalogTextUniqueIndexOid(Oid relid)
159
0
{
160
0
  switch (relid)
161
0
  {
162
0
    case ParameterAclParnameIndexId:
163
0
    case ReplicationOriginNameIndex:
164
0
    case SecLabelObjectIndexId:
165
0
    case SharedSecLabelObjectIndexId:
166
0
      return true;
167
0
  }
168
0
  return false;
169
0
}
170
171
/*
172
 * IsInplaceUpdateRelation
173
 *    True iff core code performs inplace updates on the relation.
174
 *
175
 *    This is used for assertions and for making the executor follow the
176
 *    locking protocol described at README.tuplock section "Locking to write
177
 *    inplace-updated tables".  Extensions may inplace-update other heap
178
 *    tables, but concurrent SQL UPDATE on the same table may overwrite
179
 *    those modifications.
180
 *
181
 *    The executor can assume these are not partitions or partitioned and
182
 *    have no triggers.
183
 */
184
bool
185
IsInplaceUpdateRelation(Relation relation)
186
0
{
187
0
  return IsInplaceUpdateOid(RelationGetRelid(relation));
188
0
}
189
190
/*
191
 * IsInplaceUpdateOid
192
 *    Like the above, but takes an OID as argument.
193
 */
194
bool
195
IsInplaceUpdateOid(Oid relid)
196
0
{
197
0
  return (relid == RelationRelationId ||
198
0
      relid == DatabaseRelationId);
199
0
}
200
201
/*
202
 * IsToastRelation
203
 *    True iff relation is a TOAST support relation (or index).
204
 *
205
 *    Does not perform any catalog accesses.
206
 */
207
bool
208
IsToastRelation(Relation relation)
209
0
{
210
  /*
211
   * What we actually check is whether the relation belongs to a pg_toast
212
   * namespace.  This should be equivalent because of restrictions that are
213
   * enforced elsewhere against creating user relations in, or moving
214
   * relations into/out of, a pg_toast namespace.  Notice also that this
215
   * will not say "true" for toast tables belonging to other sessions' temp
216
   * tables; we expect that other mechanisms will prevent access to those.
217
   */
218
0
  return IsToastNamespace(RelationGetNamespace(relation));
219
0
}
220
221
/*
222
 * IsToastClass
223
 *    Like the above, but takes a Form_pg_class as argument.
224
 *    Used when we do not want to open the relation and have to
225
 *    search pg_class directly.
226
 */
227
bool
228
IsToastClass(Form_pg_class reltuple)
229
0
{
230
0
  Oid     relnamespace = reltuple->relnamespace;
231
232
0
  return IsToastNamespace(relnamespace);
233
0
}
234
235
/*
236
 * IsConflictLogTableClass
237
 *    True iff pg_class tuple represents a Conflict Log Table.
238
 *
239
 *    Does not perform any catalog accesses.
240
 */
241
bool
242
IsConflictLogTableClass(Form_pg_class reltuple)
243
0
{
244
0
  Oid     relnamespace = reltuple->relnamespace;
245
246
0
  return IsConflictLogTableNamespace(relnamespace);
247
0
}
248
249
/*
250
 * IsCatalogNamespace
251
 *    True iff namespace is pg_catalog.
252
 *
253
 *    Does not perform any catalog accesses.
254
 *
255
 * NOTE: the reason this isn't a macro is to avoid having to include
256
 * catalog/pg_namespace.h in a lot of places.
257
 */
258
bool
259
IsCatalogNamespace(Oid namespaceId)
260
0
{
261
0
  return namespaceId == PG_CATALOG_NAMESPACE;
262
0
}
263
264
/*
265
 * IsToastNamespace
266
 *    True iff namespace is pg_toast or my temporary-toast-table namespace.
267
 *
268
 *    Does not perform any catalog accesses.
269
 *
270
 * Note: this will return false for temporary-toast-table namespaces belonging
271
 * to other backends.  Those are treated the same as other backends' regular
272
 * temp table namespaces, and access is prevented where appropriate.
273
 * If you need to check for those, you may be able to use isAnyTempNamespace,
274
 * but beware that that does involve a catalog access.
275
 */
276
bool
277
IsToastNamespace(Oid namespaceId)
278
0
{
279
0
  return (namespaceId == PG_TOAST_NAMESPACE) ||
280
0
    isTempToastNamespace(namespaceId);
281
0
}
282
283
/*
284
 * IsConflictLogTableNamespace
285
 *    True iff namespace is pg_conflict.
286
 *
287
 *    Does not perform any catalog accesses.
288
 */
289
bool
290
IsConflictLogTableNamespace(Oid namespaceId)
291
0
{
292
0
  return namespaceId == PG_CONFLICT_NAMESPACE;
293
0
}
294
295
/*
296
 * IsReservedName
297
 *    True iff name starts with the pg_ prefix.
298
 *
299
 *    For some classes of objects, the prefix pg_ is reserved for
300
 *    system objects only.  As of 8.0, this was only true for
301
 *    schema and tablespace names.  With 9.6, this is also true
302
 *    for roles.
303
 */
304
bool
305
IsReservedName(const char *name)
306
0
{
307
  /* ugly coding for speed */
308
0
  return (name[0] == 'p' &&
309
0
      name[1] == 'g' &&
310
0
      name[2] == '_');
311
0
}
312
313
314
/*
315
 * IsSharedRelation
316
 *    Given the OID of a relation, determine whether it's supposed to be
317
 *    shared across an entire database cluster.
318
 *
319
 * In older releases, this had to be hard-wired so that we could compute the
320
 * locktag for a relation and lock it before examining its catalog entry.
321
 * Since we now have MVCC catalog access, the race conditions that made that
322
 * a hard requirement are gone, so we could look at relaxing this restriction.
323
 * However, if we scanned the pg_class entry to find relisshared, and only
324
 * then locked the relation, pg_class could get updated in the meantime,
325
 * forcing us to scan the relation again, which would definitely be complex
326
 * and might have undesirable performance consequences.  Fortunately, the set
327
 * of shared relations is fairly static, so a hand-maintained list of their
328
 * OIDs isn't completely impractical.
329
 */
330
bool
331
IsSharedRelation(Oid relationId)
332
0
{
333
  /* These are the shared catalogs (look for BKI_SHARED_RELATION) */
334
0
  if (relationId == AuthIdRelationId ||
335
0
    relationId == AuthMemRelationId ||
336
0
    relationId == DatabaseRelationId ||
337
0
    relationId == DbRoleSettingRelationId ||
338
0
    relationId == ParameterAclRelationId ||
339
0
    relationId == ReplicationOriginRelationId ||
340
0
    relationId == SharedDependRelationId ||
341
0
    relationId == SharedDescriptionRelationId ||
342
0
    relationId == SharedSecLabelRelationId ||
343
0
    relationId == SubscriptionRelationId ||
344
0
    relationId == TableSpaceRelationId)
345
0
    return true;
346
  /* These are their indexes */
347
0
  if (relationId == AuthIdOidIndexId ||
348
0
    relationId == AuthIdRolnameIndexId ||
349
0
    relationId == AuthMemMemRoleIndexId ||
350
0
    relationId == AuthMemRoleMemIndexId ||
351
0
    relationId == AuthMemOidIndexId ||
352
0
    relationId == AuthMemGrantorIndexId ||
353
0
    relationId == DatabaseNameIndexId ||
354
0
    relationId == DatabaseOidIndexId ||
355
0
    relationId == DbRoleSettingDatidRolidIndexId ||
356
0
    relationId == ParameterAclOidIndexId ||
357
0
    relationId == ParameterAclParnameIndexId ||
358
0
    relationId == ReplicationOriginIdentIndex ||
359
0
    relationId == ReplicationOriginNameIndex ||
360
0
    relationId == SharedDependDependerIndexId ||
361
0
    relationId == SharedDependReferenceIndexId ||
362
0
    relationId == SharedDescriptionObjIndexId ||
363
0
    relationId == SharedSecLabelObjectIndexId ||
364
0
    relationId == SubscriptionNameIndexId ||
365
0
    relationId == SubscriptionObjectIndexId ||
366
0
    relationId == TablespaceNameIndexId ||
367
0
    relationId == TablespaceOidIndexId)
368
0
    return true;
369
  /* These are their toast tables and toast indexes */
370
0
  if (relationId == PgDatabaseToastTable ||
371
0
    relationId == PgDatabaseToastIndex ||
372
0
    relationId == PgDbRoleSettingToastTable ||
373
0
    relationId == PgDbRoleSettingToastIndex ||
374
0
    relationId == PgParameterAclToastTable ||
375
0
    relationId == PgParameterAclToastIndex ||
376
0
    relationId == PgShdescriptionToastTable ||
377
0
    relationId == PgShdescriptionToastIndex ||
378
0
    relationId == PgShseclabelToastTable ||
379
0
    relationId == PgShseclabelToastIndex ||
380
0
    relationId == PgSubscriptionToastTable ||
381
0
    relationId == PgSubscriptionToastIndex ||
382
0
    relationId == PgTablespaceToastTable ||
383
0
    relationId == PgTablespaceToastIndex)
384
0
    return true;
385
0
  return false;
386
0
}
387
388
/*
389
 * IsPinnedObject
390
 *    Given the class + OID identity of a database object, report whether
391
 *    it is "pinned", that is not droppable because the system requires it.
392
 *
393
 * We used to represent this explicitly in pg_depend, but that proved to be
394
 * an undesirable amount of overhead, so now we rely on an OID range test.
395
 */
396
bool
397
IsPinnedObject(Oid classId, Oid objectId)
398
0
{
399
  /*
400
   * Objects with OIDs above FirstUnpinnedObjectId are never pinned.  Since
401
   * the OID generator skips this range when wrapping around, this check
402
   * guarantees that user-defined objects are never considered pinned.
403
   */
404
0
  if (objectId >= FirstUnpinnedObjectId)
405
0
    return false;
406
407
  /*
408
   * Large objects are never pinned.  We need this special case because
409
   * their OIDs can be user-assigned.
410
   */
411
0
  if (classId == LargeObjectRelationId)
412
0
    return false;
413
414
  /*
415
   * There are a few objects defined in the catalog .dat files that, as a
416
   * matter of policy, we prefer not to treat as pinned.  We used to handle
417
   * that by excluding them from pg_depend, but it's just as easy to
418
   * hard-wire their OIDs here.  (If the user does indeed drop and recreate
419
   * them, they'll have new but certainly-unpinned OIDs, so no problem.)
420
   *
421
   * Checking both classId and objectId is overkill, since OIDs below
422
   * FirstGenbkiObjectId should be globally unique, but do it anyway for
423
   * robustness.
424
   */
425
426
  /* the public namespace is not pinned */
427
0
  if (classId == NamespaceRelationId &&
428
0
    objectId == PG_PUBLIC_NAMESPACE)
429
0
    return false;
430
431
  /*
432
   * Databases are never pinned.  It might seem that it'd be prudent to pin
433
   * at least template0; but we do this intentionally so that template0 and
434
   * template1 can be rebuilt from each other, thus letting them serve as
435
   * mutual backups (as long as you've not modified template1, anyway).
436
   */
437
0
  if (classId == DatabaseRelationId)
438
0
    return false;
439
440
  /*
441
   * All other initdb-created objects are pinned.  This is overkill (the
442
   * system doesn't really depend on having every last weird datatype, for
443
   * instance) but generating only the minimum required set of dependencies
444
   * seems hard, and enforcing an accurate list would be much more expensive
445
   * than the simple range test used here.
446
   */
447
0
  return true;
448
0
}
449
450
451
/*
452
 * GetNewOidWithIndex
453
 *    Generate a new OID that is unique within the system relation.
454
 *
455
 * Since the OID is not immediately inserted into the table, there is a
456
 * race condition here; but a problem could occur only if someone else
457
 * managed to cycle through 2^32 OIDs and generate the same OID before we
458
 * finish inserting our row.  This seems unlikely to be a problem.  Note
459
 * that if we had to *commit* the row to end the race condition, the risk
460
 * would be rather higher; therefore we use SnapshotAny in the test, so that
461
 * we will see uncommitted rows.  (We used to use SnapshotDirty, but that has
462
 * the disadvantage that it ignores recently-deleted rows, creating a risk
463
 * of transient conflicts for as long as our own MVCC snapshots think a
464
 * recently-deleted row is live.  The risk is far higher when selecting TOAST
465
 * OIDs, because SnapshotToast considers dead rows as active indefinitely.)
466
 *
467
 * Note that we are effectively assuming that the table has a relatively small
468
 * number of entries (much less than 2^32) and there aren't very long runs of
469
 * consecutive existing OIDs.  This is a mostly reasonable assumption for
470
 * system catalogs.
471
 *
472
 * Caller must have a suitable lock on the relation.
473
 */
474
Oid
475
GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
476
{
477
  Oid     newOid;
478
  SysScanDesc scan;
479
  ScanKeyData key;
480
  bool    collides;
481
  uint64    retries = 0;
482
  uint64    retries_before_log = GETNEWOID_LOG_THRESHOLD;
483
484
  /* Only system relations are supported */
485
  Assert(IsSystemRelation(relation));
486
487
  /* In bootstrap mode, we don't have any indexes to use */
488
  if (IsBootstrapProcessingMode())
489
    return GetNewObjectId();
490
491
  /*
492
   * We should never be asked to generate a new pg_type OID during
493
   * pg_upgrade; doing so would risk collisions with the OIDs it wants to
494
   * assign.  Hitting this assert means there's some path where we failed to
495
   * ensure that a type OID is determined by commands in the dump script.
496
   */
497
  Assert(!IsBinaryUpgrade || RelationGetRelid(relation) != TypeRelationId);
498
499
  /* Generate new OIDs until we find one not in the table */
500
  do
501
  {
502
    CHECK_FOR_INTERRUPTS();
503
504
    newOid = GetNewObjectId();
505
506
    ScanKeyInit(&key,
507
          oidcolumn,
508
          BTEqualStrategyNumber, F_OIDEQ,
509
          ObjectIdGetDatum(newOid));
510
511
    /* see notes above about using SnapshotAny */
512
    scan = systable_beginscan(relation, indexId, true,
513
                  SnapshotAny, 1, &key);
514
515
    collides = HeapTupleIsValid(systable_getnext(scan));
516
517
    systable_endscan(scan);
518
519
    /*
520
     * Log that we iterate more than GETNEWOID_LOG_THRESHOLD but have not
521
     * yet found OID unused in the relation. Then repeat logging with
522
     * exponentially increasing intervals until we iterate more than
523
     * GETNEWOID_LOG_MAX_INTERVAL. Finally repeat logging every
524
     * GETNEWOID_LOG_MAX_INTERVAL unless an unused OID is found. This
525
     * logic is necessary not to fill up the server log with the similar
526
     * messages.
527
     */
528
    if (retries >= retries_before_log)
529
    {
530
      ereport(LOG,
531
          (errmsg("still searching for an unused OID in relation \"%s\"",
532
              RelationGetRelationName(relation)),
533
           errdetail_plural("OID candidates have been checked %" PRIu64 " time, but no unused OID has been found yet.",
534
                    "OID candidates have been checked %" PRIu64 " times, but no unused OID has been found yet.",
535
                    retries,
536
                    retries)));
537
538
      /*
539
       * Double the number of retries to do before logging next until it
540
       * reaches GETNEWOID_LOG_MAX_INTERVAL.
541
       */
542
      if (retries_before_log * 2 <= GETNEWOID_LOG_MAX_INTERVAL)
543
        retries_before_log *= 2;
544
      else
545
        retries_before_log += GETNEWOID_LOG_MAX_INTERVAL;
546
    }
547
548
    retries++;
549
  } while (collides);
550
551
  /*
552
   * If at least one log message is emitted, also log the completion of OID
553
   * assignment.
554
   */
555
  if (retries > GETNEWOID_LOG_THRESHOLD)
556
  {
557
    ereport(LOG,
558
        (errmsg_plural("new OID has been assigned in relation \"%s\" after %" PRIu64 " retry",
559
                 "new OID has been assigned in relation \"%s\" after %" PRIu64 " retries",
560
                 retries,
561
                 RelationGetRelationName(relation), retries)));
562
  }
563
564
  return newOid;
565
}
566
567
/*
568
 * GetNewRelFileNumber
569
 *    Generate a new relfilenumber that is unique within the
570
 *    database of the given tablespace.
571
 *
572
 * If the relfilenumber will also be used as the relation's OID, pass the
573
 * opened pg_class catalog, and this routine will guarantee that the result
574
 * is also an unused OID within pg_class.  If the result is to be used only
575
 * as a relfilenumber for an existing relation, pass NULL for pg_class.
576
 *
577
 * As with GetNewOidWithIndex(), there is some theoretical risk of a race
578
 * condition, but it doesn't seem worth worrying about.
579
 *
580
 * Note: we don't support using this in bootstrap mode.  All relations
581
 * created by bootstrap have preassigned OIDs, so there's no need.
582
 */
583
RelFileNumber
584
GetNewRelFileNumber(Oid reltablespace, Relation pg_class, char relpersistence)
585
0
{
586
0
  RelFileLocatorBackend rlocator;
587
0
  RelPathStr  rpath;
588
0
  bool    collides;
589
0
  ProcNumber  procNumber;
590
591
  /*
592
   * If we ever get here during pg_upgrade, there's something wrong; all
593
   * relfilenumber assignments during a binary-upgrade run should be
594
   * determined by commands in the dump script.
595
   */
596
0
  Assert(!IsBinaryUpgrade);
597
598
0
  switch (relpersistence)
599
0
  {
600
0
    case RELPERSISTENCE_TEMP:
601
0
      procNumber = ProcNumberForTempRelations();
602
0
      break;
603
0
    case RELPERSISTENCE_UNLOGGED:
604
0
    case RELPERSISTENCE_PERMANENT:
605
0
      procNumber = INVALID_PROC_NUMBER;
606
0
      break;
607
0
    default:
608
0
      elog(ERROR, "invalid relpersistence: %c", relpersistence);
609
0
      return InvalidRelFileNumber; /* placate compiler */
610
0
  }
611
612
  /* This logic should match RelationInitPhysicalAddr */
613
0
  rlocator.locator.spcOid = reltablespace ? reltablespace : MyDatabaseTableSpace;
614
0
  rlocator.locator.dbOid =
615
0
    (rlocator.locator.spcOid == GLOBALTABLESPACE_OID) ?
616
0
    InvalidOid : MyDatabaseId;
617
618
  /*
619
   * The relpath will vary based on the backend number, so we must
620
   * initialize that properly here to make sure that any collisions based on
621
   * filename are properly detected.
622
   */
623
0
  rlocator.backend = procNumber;
624
625
0
  do
626
0
  {
627
0
    CHECK_FOR_INTERRUPTS();
628
629
    /* Generate the OID */
630
0
    if (pg_class)
631
0
      rlocator.locator.relNumber = GetNewOidWithIndex(pg_class, ClassOidIndexId,
632
0
                              Anum_pg_class_oid);
633
0
    else
634
0
      rlocator.locator.relNumber = GetNewObjectId();
635
636
    /* Check for existing file of same name */
637
0
    rpath = relpath(rlocator, MAIN_FORKNUM);
638
639
0
    if (access(rpath.str, F_OK) == 0)
640
0
    {
641
      /* definite collision */
642
0
      collides = true;
643
0
    }
644
0
    else
645
0
    {
646
      /*
647
       * Here we have a little bit of a dilemma: if errno is something
648
       * other than ENOENT, should we declare a collision and loop? In
649
       * practice it seems best to go ahead regardless of the errno.  If
650
       * there is a colliding file we will get an smgr failure when we
651
       * attempt to create the new relation file.
652
       */
653
0
      collides = false;
654
0
    }
655
0
  } while (collides);
656
657
0
  return rlocator.locator.relNumber;
658
0
}
659
660
/*
661
 * SQL callable interface for GetNewOidWithIndex().  Outside of initdb's
662
 * direct insertions into catalog tables, and recovering from corruption, this
663
 * should rarely be needed.
664
 *
665
 * Function is intentionally not documented in the user facing docs.
666
 */
667
Datum
668
pg_nextoid(PG_FUNCTION_ARGS)
669
0
{
670
0
  Oid     reloid = PG_GETARG_OID(0);
671
0
  Name    attname = PG_GETARG_NAME(1);
672
0
  Oid     idxoid = PG_GETARG_OID(2);
673
0
  Relation  rel;
674
0
  Relation  idx;
675
0
  HeapTuple atttuple;
676
0
  Form_pg_attribute attform;
677
0
  AttrNumber  attno;
678
0
  Oid     newoid;
679
680
  /*
681
   * As this function is not intended to be used during normal running, and
682
   * only supports system catalogs (which require superuser permissions to
683
   * modify), just checking for superuser ought to not obstruct valid
684
   * usecases.
685
   */
686
0
  if (!superuser())
687
0
    ereport(ERROR,
688
0
        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
689
0
         errmsg("must be superuser to call %s()",
690
0
            "pg_nextoid")));
691
692
0
  rel = table_open(reloid, RowExclusiveLock);
693
0
  idx = index_open(idxoid, RowExclusiveLock);
694
695
0
  if (!IsSystemRelation(rel))
696
0
    ereport(ERROR,
697
0
        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
698
0
         errmsg("pg_nextoid() can only be used on system catalogs")));
699
700
0
  if (idx->rd_index->indrelid != RelationGetRelid(rel))
701
0
    ereport(ERROR,
702
0
        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
703
0
         errmsg("index \"%s\" does not belong to table \"%s\"",
704
0
            RelationGetRelationName(idx),
705
0
            RelationGetRelationName(rel))));
706
707
0
  atttuple = SearchSysCacheAttName(reloid, NameStr(*attname));
708
0
  if (!HeapTupleIsValid(atttuple))
709
0
    ereport(ERROR,
710
0
        (errcode(ERRCODE_UNDEFINED_COLUMN),
711
0
         errmsg("column \"%s\" of relation \"%s\" does not exist",
712
0
            NameStr(*attname), RelationGetRelationName(rel))));
713
714
0
  attform = ((Form_pg_attribute) GETSTRUCT(atttuple));
715
0
  attno = attform->attnum;
716
717
0
  if (attform->atttypid != OIDOID)
718
0
    ereport(ERROR,
719
0
        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
720
0
         errmsg("column \"%s\" is not of type %s",
721
0
            NameStr(*attname), "oid")));
722
723
0
  if (IndexRelationGetNumberOfKeyAttributes(idx) != 1 ||
724
0
    idx->rd_index->indkey.values[0] != attno)
725
0
    ereport(ERROR,
726
0
        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
727
0
         errmsg("index \"%s\" is not the index for column \"%s\"",
728
0
            RelationGetRelationName(idx),
729
0
            NameStr(*attname))));
730
731
0
  newoid = GetNewOidWithIndex(rel, idxoid, attno);
732
733
0
  ReleaseSysCache(atttuple);
734
0
  table_close(rel, RowExclusiveLock);
735
0
  index_close(idx, RowExclusiveLock);
736
737
0
  PG_RETURN_OID(newoid);
738
0
}
739
740
/*
741
 * SQL callable interface for StopGeneratingPinnedObjectIds().
742
 *
743
 * This is only to be used by initdb, so it's intentionally not documented in
744
 * the user facing docs.
745
 */
746
Datum
747
pg_stop_making_pinned_objects(PG_FUNCTION_ARGS)
748
0
{
749
  /*
750
   * Belt-and-suspenders check, since StopGeneratingPinnedObjectIds will
751
   * fail anyway in non-single-user mode.
752
   */
753
0
  if (!superuser())
754
0
    ereport(ERROR,
755
0
        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
756
0
         errmsg("must be superuser to call %s()",
757
0
            "pg_stop_making_pinned_objects")));
758
759
0
  StopGeneratingPinnedObjectIds();
760
761
0
  PG_RETURN_VOID();
762
0
}