Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * pg_inherits.c
4 : * routines to support manipulation of the pg_inherits relation
5 : *
6 : * Note: currently, this module mostly contains inquiry functions; actual
7 : * creation and deletion of pg_inherits entries is mostly done in tablecmds.c.
8 : * Perhaps someday that code should be moved here, but it'd have to be
9 : * disentangled from other stuff such as pg_depend updates.
10 : *
11 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
12 : * Portions Copyright (c) 1994, Regents of the University of California
13 : *
14 : *
15 : * IDENTIFICATION
16 : * src/backend/catalog/pg_inherits.c
17 : *
18 : *-------------------------------------------------------------------------
19 : */
20 : #include "postgres.h"
21 :
22 : #include "access/genam.h"
23 : #include "access/htup_details.h"
24 : #include "access/table.h"
25 : #include "catalog/indexing.h"
26 : #include "catalog/pg_inherits.h"
27 : #include "parser/parse_type.h"
28 : #include "storage/lmgr.h"
29 : #include "utils/builtins.h"
30 : #include "utils/fmgroids.h"
31 : #include "utils/snapmgr.h"
32 : #include "utils/syscache.h"
33 :
34 : /*
35 : * Entry of a hash table used in find_all_inheritors. See below.
36 : */
37 : typedef struct SeenRelsEntry
38 : {
39 : Oid rel_id; /* relation oid */
40 : int list_index; /* its position in output list(s) */
41 : } SeenRelsEntry;
42 :
43 : /*
44 : * find_inheritance_children
45 : *
46 : * Returns a list containing the OIDs of all relations which
47 : * inherit *directly* from the relation with OID 'parentrelId'.
48 : *
49 : * The specified lock type is acquired on each child relation (but not on the
50 : * given rel; caller should already have locked it). If lockmode is NoLock
51 : * then no locks are acquired, but caller must beware of race conditions
52 : * against possible DROPs of child relations.
53 : *
54 : * Partitions marked as being detached are omitted; see
55 : * find_inheritance_children_extended for details.
56 : */
57 : List *
58 87168 : find_inheritance_children(Oid parentrelId, LOCKMODE lockmode)
59 : {
60 87168 : return find_inheritance_children_extended(parentrelId, true, lockmode,
61 : NULL, NULL);
62 : }
63 :
64 : /*
65 : * find_inheritance_children_extended
66 : *
67 : * As find_inheritance_children, with more options regarding detached
68 : * partitions.
69 : *
70 : * If a partition's pg_inherits row is marked "detach pending",
71 : * *detached_exist (if not null) is set true.
72 : *
73 : * If omit_detached is true and there is an active snapshot (not the same as
74 : * the catalog snapshot used to scan pg_inherits!) and a pg_inherits tuple
75 : * marked "detach pending" is visible to that snapshot, then that partition is
76 : * omitted from the output list. This makes partitions invisible depending on
77 : * whether the transaction that marked those partitions as detached appears
78 : * committed to the active snapshot. In addition, *detached_xmin (if not null)
79 : * is set to the xmin of the row of the detached partition.
80 : */
81 : List *
82 108408 : find_inheritance_children_extended(Oid parentrelId, bool omit_detached,
83 : LOCKMODE lockmode, bool *detached_exist,
84 : TransactionId *detached_xmin)
85 : {
86 108408 : List *list = NIL;
87 : Relation relation;
88 : SysScanDesc scan;
89 : ScanKeyData key[1];
90 : HeapTuple inheritsTuple;
91 : Oid inhrelid;
92 : Oid *oidarr;
93 : int maxoids,
94 : numoids,
95 : i;
96 :
97 : /*
98 : * Can skip the scan if pg_class shows the relation has never had a
99 : * subclass.
100 : */
101 108408 : if (!has_subclass(parentrelId))
102 77912 : return NIL;
103 :
104 : /*
105 : * Scan pg_inherits and build a working array of subclass OIDs.
106 : */
107 30496 : maxoids = 32;
108 30496 : oidarr = (Oid *) palloc(maxoids * sizeof(Oid));
109 30496 : numoids = 0;
110 :
111 30496 : relation = table_open(InheritsRelationId, AccessShareLock);
112 :
113 30496 : ScanKeyInit(&key[0],
114 : Anum_pg_inherits_inhparent,
115 : BTEqualStrategyNumber, F_OIDEQ,
116 : ObjectIdGetDatum(parentrelId));
117 :
118 30496 : scan = systable_beginscan(relation, InheritsParentIndexId, true,
119 : NULL, 1, key);
120 :
121 87976 : while ((inheritsTuple = systable_getnext(scan)) != NULL)
122 : {
123 : /*
124 : * Cope with partitions concurrently being detached. When we see a
125 : * partition marked "detach pending", we omit it from the returned set
126 : * of visible partitions if caller requested that and the tuple's xmin
127 : * does not appear in progress to the active snapshot. (If there's no
128 : * active snapshot set, that means we're not running a user query, so
129 : * it's OK to always include detached partitions in that case; if the
130 : * xmin is still running to the active snapshot, then the partition
131 : * has not been detached yet and so we include it.)
132 : *
133 : * The reason for this hack is that we want to avoid seeing the
134 : * partition as alive in RI queries during REPEATABLE READ or
135 : * SERIALIZABLE transactions: such queries use a different snapshot
136 : * than the one used by regular (user) queries.
137 : */
138 57480 : if (((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhdetachpending)
139 : {
140 116 : if (detached_exist)
141 112 : *detached_exist = true;
142 :
143 116 : if (omit_detached && ActiveSnapshotSet())
144 : {
145 : TransactionId xmin;
146 : Snapshot snap;
147 :
148 94 : xmin = HeapTupleHeaderGetXmin(inheritsTuple->t_data);
149 94 : snap = GetActiveSnapshot();
150 :
151 94 : if (!XidInMVCCSnapshot(xmin, snap))
152 : {
153 70 : if (detached_xmin)
154 : {
155 : /*
156 : * Two detached partitions should not occur (see
157 : * checks in MarkInheritDetached), but if they do,
158 : * track the newer of the two. Make sure to warn the
159 : * user, so that they can clean up. Since this is
160 : * just a cross-check against potentially corrupt
161 : * catalogs, we don't make it a full-fledged error
162 : * message.
163 : */
164 66 : if (*detached_xmin != InvalidTransactionId)
165 : {
166 0 : elog(WARNING, "more than one partition pending detach found for table with OID %u",
167 : parentrelId);
168 0 : if (TransactionIdFollows(xmin, *detached_xmin))
169 0 : *detached_xmin = xmin;
170 : }
171 : else
172 66 : *detached_xmin = xmin;
173 : }
174 :
175 : /* Don't add the partition to the output list */
176 70 : continue;
177 : }
178 : }
179 : }
180 :
181 57410 : inhrelid = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhrelid;
182 57410 : if (numoids >= maxoids)
183 : {
184 0 : maxoids *= 2;
185 0 : oidarr = (Oid *) repalloc(oidarr, maxoids * sizeof(Oid));
186 : }
187 57410 : oidarr[numoids++] = inhrelid;
188 : }
189 :
190 30496 : systable_endscan(scan);
191 :
192 30496 : table_close(relation, AccessShareLock);
193 :
194 : /*
195 : * If we found more than one child, sort them by OID. This ensures
196 : * reasonably consistent behavior regardless of the vagaries of an
197 : * indexscan. This is important since we need to be sure all backends
198 : * lock children in the same order to avoid needless deadlocks.
199 : */
200 30496 : if (numoids > 1)
201 17000 : qsort(oidarr, numoids, sizeof(Oid), oid_cmp);
202 :
203 : /*
204 : * Acquire locks and build the result list.
205 : */
206 87906 : for (i = 0; i < numoids; i++)
207 : {
208 57410 : inhrelid = oidarr[i];
209 :
210 57410 : if (lockmode != NoLock)
211 : {
212 : /* Get the lock to synchronize against concurrent drop */
213 17798 : LockRelationOid(inhrelid, lockmode);
214 :
215 : /*
216 : * Now that we have the lock, double-check to see if the relation
217 : * really exists or not. If not, assume it was dropped while we
218 : * waited to acquire lock, and ignore it.
219 : */
220 17798 : if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(inhrelid)))
221 : {
222 : /* Release useless lock */
223 2 : UnlockRelationOid(inhrelid, lockmode);
224 : /* And ignore this relation */
225 2 : continue;
226 : }
227 : }
228 :
229 57408 : list = lappend_oid(list, inhrelid);
230 : }
231 :
232 30496 : pfree(oidarr);
233 :
234 30496 : return list;
235 : }
236 :
237 :
238 : /*
239 : * find_all_inheritors -
240 : * Returns a list of relation OIDs including the given rel plus
241 : * all relations that inherit from it, directly or indirectly.
242 : * Optionally, it also returns the number of parents found for
243 : * each such relation within the inheritance tree rooted at the
244 : * given rel.
245 : *
246 : * The specified lock type is acquired on all child relations (but not on the
247 : * given rel; caller should already have locked it). If lockmode is NoLock
248 : * then no locks are acquired, but caller must beware of race conditions
249 : * against possible DROPs of child relations.
250 : *
251 : * NB - No current callers of this routine are interested in children being
252 : * concurrently detached, so there's no provision to include them.
253 : */
254 : List *
255 48850 : find_all_inheritors(Oid parentrelId, LOCKMODE lockmode, List **numparents)
256 : {
257 : /* hash table for O(1) rel_oid -> rel_numparents cell lookup */
258 : HTAB *seen_rels;
259 : HASHCTL ctl;
260 : List *rels_list,
261 : *rel_numparents;
262 : ListCell *l;
263 :
264 48850 : ctl.keysize = sizeof(Oid);
265 48850 : ctl.entrysize = sizeof(SeenRelsEntry);
266 48850 : ctl.hcxt = CurrentMemoryContext;
267 :
268 48850 : seen_rels = hash_create("find_all_inheritors temporary table",
269 : 32, /* start small and extend */
270 : &ctl,
271 : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
272 :
273 : /*
274 : * We build a list starting with the given rel and adding all direct and
275 : * indirect children. We can use a single list as both the record of
276 : * already-found rels and the agenda of rels yet to be scanned for more
277 : * children. This is a bit tricky but works because the foreach() macro
278 : * doesn't fetch the next list element until the bottom of the loop. Note
279 : * that we can't keep pointers into the output lists; but an index is
280 : * sufficient.
281 : */
282 48850 : rels_list = list_make1_oid(parentrelId);
283 48850 : rel_numparents = list_make1_int(0);
284 :
285 120812 : foreach(l, rels_list)
286 : {
287 71962 : Oid currentrel = lfirst_oid(l);
288 : List *currentchildren;
289 : ListCell *lc;
290 :
291 : /* Get the direct children of this rel */
292 71962 : currentchildren = find_inheritance_children(currentrel, lockmode);
293 :
294 : /*
295 : * Add to the queue only those children not already seen. This avoids
296 : * making duplicate entries in case of multiple inheritance paths from
297 : * the same parent. (It'll also keep us from getting into an infinite
298 : * loop, though theoretically there can't be any cycles in the
299 : * inheritance graph anyway.)
300 : */
301 95540 : foreach(lc, currentchildren)
302 : {
303 23578 : Oid child_oid = lfirst_oid(lc);
304 : bool found;
305 : SeenRelsEntry *hash_entry;
306 :
307 23578 : hash_entry = hash_search(seen_rels, &child_oid, HASH_ENTER, &found);
308 23578 : if (found)
309 : {
310 : /* if the rel is already there, bump number-of-parents counter */
311 : ListCell *numparents_cell;
312 :
313 466 : numparents_cell = list_nth_cell(rel_numparents,
314 : hash_entry->list_index);
315 466 : lfirst_int(numparents_cell)++;
316 : }
317 : else
318 : {
319 : /* if it's not there, add it. expect 1 parent, initially. */
320 23112 : hash_entry->list_index = list_length(rels_list);
321 23112 : rels_list = lappend_oid(rels_list, child_oid);
322 23112 : rel_numparents = lappend_int(rel_numparents, 1);
323 : }
324 : }
325 : }
326 :
327 48850 : if (numparents)
328 1056 : *numparents = rel_numparents;
329 : else
330 47794 : list_free(rel_numparents);
331 :
332 48850 : hash_destroy(seen_rels);
333 :
334 48850 : return rels_list;
335 : }
336 :
337 :
338 : /*
339 : * has_subclass - does this relation have any children?
340 : *
341 : * In the current implementation, has_subclass returns whether a
342 : * particular class *might* have a subclass. It will not return the
343 : * correct result if a class had a subclass which was later dropped.
344 : * This is because relhassubclass in pg_class is not updated immediately
345 : * when a subclass is dropped, primarily because of concurrency concerns.
346 : *
347 : * Currently has_subclass is only used as an efficiency hack to skip
348 : * unnecessary inheritance searches, so this is OK. Note that ANALYZE
349 : * on a childless table will clean up the obsolete relhassubclass flag.
350 : *
351 : * Although this doesn't actually touch pg_inherits, it seems reasonable
352 : * to keep it here since it's normally used with the other routines here.
353 : */
354 : bool
355 454974 : has_subclass(Oid relationId)
356 : {
357 : HeapTuple tuple;
358 : bool result;
359 :
360 454974 : tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relationId));
361 454974 : if (!HeapTupleIsValid(tuple))
362 0 : elog(ERROR, "cache lookup failed for relation %u", relationId);
363 :
364 454974 : result = ((Form_pg_class) GETSTRUCT(tuple))->relhassubclass;
365 454974 : ReleaseSysCache(tuple);
366 454974 : return result;
367 : }
368 :
369 : /*
370 : * has_superclass - does this relation inherit from another?
371 : *
372 : * Unlike has_subclass, this can be relied on to give an accurate answer.
373 : * However, the caller must hold a lock on the given relation so that it
374 : * can't be concurrently added to or removed from an inheritance hierarchy.
375 : */
376 : bool
377 626 : has_superclass(Oid relationId)
378 : {
379 : Relation catalog;
380 : SysScanDesc scan;
381 : ScanKeyData skey;
382 : bool result;
383 :
384 626 : catalog = table_open(InheritsRelationId, AccessShareLock);
385 626 : ScanKeyInit(&skey, Anum_pg_inherits_inhrelid, BTEqualStrategyNumber,
386 : F_OIDEQ, ObjectIdGetDatum(relationId));
387 626 : scan = systable_beginscan(catalog, InheritsRelidSeqnoIndexId, true,
388 : NULL, 1, &skey);
389 626 : result = HeapTupleIsValid(systable_getnext(scan));
390 626 : systable_endscan(scan);
391 626 : table_close(catalog, AccessShareLock);
392 :
393 626 : return result;
394 : }
395 :
396 : /*
397 : * Given two type OIDs, determine whether the first is a complex type
398 : * (class type) that inherits from the second.
399 : *
400 : * This essentially asks whether the first type is guaranteed to be coercible
401 : * to the second. Therefore, we allow the first type to be a domain over a
402 : * complex type that inherits from the second; that creates no difficulties.
403 : * But the second type cannot be a domain.
404 : */
405 : bool
406 680952 : typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId)
407 : {
408 680952 : bool result = false;
409 : Oid subclassRelid;
410 : Oid superclassRelid;
411 : Relation inhrel;
412 : List *visited,
413 : *queue;
414 : ListCell *queue_item;
415 :
416 : /* We need to work with the associated relation OIDs */
417 680952 : subclassRelid = typeOrDomainTypeRelid(subclassTypeId);
418 680952 : if (subclassRelid == InvalidOid)
419 668538 : return false; /* not a complex type or domain over one */
420 12414 : superclassRelid = typeidTypeRelid(superclassTypeId);
421 12414 : if (superclassRelid == InvalidOid)
422 12282 : return false; /* not a complex type */
423 :
424 : /* No point in searching if the superclass has no subclasses */
425 132 : if (!has_subclass(superclassRelid))
426 12 : return false;
427 :
428 : /*
429 : * Begin the search at the relation itself, so add its relid to the queue.
430 : */
431 120 : queue = list_make1_oid(subclassRelid);
432 120 : visited = NIL;
433 :
434 120 : inhrel = table_open(InheritsRelationId, AccessShareLock);
435 :
436 : /*
437 : * Use queue to do a breadth-first traversal of the inheritance graph from
438 : * the relid supplied up to the root. Notice that we append to the queue
439 : * inside the loop --- this is okay because the foreach() macro doesn't
440 : * advance queue_item until the next loop iteration begins.
441 : */
442 120 : foreach(queue_item, queue)
443 : {
444 120 : Oid this_relid = lfirst_oid(queue_item);
445 : ScanKeyData skey;
446 : SysScanDesc inhscan;
447 : HeapTuple inhtup;
448 :
449 : /*
450 : * If we've seen this relid already, skip it. This avoids extra work
451 : * in multiple-inheritance scenarios, and also protects us from an
452 : * infinite loop in case there is a cycle in pg_inherits (though
453 : * theoretically that shouldn't happen).
454 : */
455 120 : if (list_member_oid(visited, this_relid))
456 0 : continue;
457 :
458 : /*
459 : * Okay, this is a not-yet-seen relid. Add it to the list of
460 : * already-visited OIDs, then find all the types this relid inherits
461 : * from and add them to the queue.
462 : */
463 120 : visited = lappend_oid(visited, this_relid);
464 :
465 120 : ScanKeyInit(&skey,
466 : Anum_pg_inherits_inhrelid,
467 : BTEqualStrategyNumber, F_OIDEQ,
468 : ObjectIdGetDatum(this_relid));
469 :
470 120 : inhscan = systable_beginscan(inhrel, InheritsRelidSeqnoIndexId, true,
471 : NULL, 1, &skey);
472 :
473 132 : while ((inhtup = systable_getnext(inhscan)) != NULL)
474 : {
475 132 : Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inhtup);
476 132 : Oid inhparent = inh->inhparent;
477 :
478 : /* If this is the target superclass, we're done */
479 132 : if (inhparent == superclassRelid)
480 : {
481 120 : result = true;
482 120 : break;
483 : }
484 :
485 : /* Else add to queue */
486 12 : queue = lappend_oid(queue, inhparent);
487 : }
488 :
489 120 : systable_endscan(inhscan);
490 :
491 120 : if (result)
492 120 : break;
493 : }
494 :
495 : /* clean up ... */
496 120 : table_close(inhrel, AccessShareLock);
497 :
498 120 : list_free(visited);
499 120 : list_free(queue);
500 :
501 120 : return result;
502 : }
503 :
504 : /*
505 : * Create a single pg_inherits row with the given data
506 : */
507 : void
508 14554 : StoreSingleInheritance(Oid relationId, Oid parentOid, int32 seqNumber)
509 : {
510 : Datum values[Natts_pg_inherits];
511 : bool nulls[Natts_pg_inherits];
512 : HeapTuple tuple;
513 : Relation inhRelation;
514 :
515 14554 : inhRelation = table_open(InheritsRelationId, RowExclusiveLock);
516 :
517 : /*
518 : * Make the pg_inherits entry
519 : */
520 14554 : values[Anum_pg_inherits_inhrelid - 1] = ObjectIdGetDatum(relationId);
521 14554 : values[Anum_pg_inherits_inhparent - 1] = ObjectIdGetDatum(parentOid);
522 14554 : values[Anum_pg_inherits_inhseqno - 1] = Int32GetDatum(seqNumber);
523 14554 : values[Anum_pg_inherits_inhdetachpending - 1] = BoolGetDatum(false);
524 :
525 14554 : memset(nulls, 0, sizeof(nulls));
526 :
527 14554 : tuple = heap_form_tuple(RelationGetDescr(inhRelation), values, nulls);
528 :
529 14554 : CatalogTupleInsert(inhRelation, tuple);
530 :
531 14554 : heap_freetuple(tuple);
532 :
533 14554 : table_close(inhRelation, RowExclusiveLock);
534 14554 : }
535 :
536 : /*
537 : * DeleteInheritsTuple
538 : *
539 : * Delete pg_inherits tuples with the given inhrelid. inhparent may be given
540 : * as InvalidOid, in which case all tuples matching inhrelid are deleted;
541 : * otherwise only delete tuples with the specified inhparent.
542 : *
543 : * expect_detach_pending is the expected state of the inhdetachpending flag.
544 : * If the catalog row does not match that state, an error is raised.
545 : *
546 : * childname is the partition name, if a table; pass NULL for regular
547 : * inheritance or when working with other relation kinds.
548 : *
549 : * Returns whether at least one row was deleted.
550 : */
551 : bool
552 23408 : DeleteInheritsTuple(Oid inhrelid, Oid inhparent, bool expect_detach_pending,
553 : const char *childname)
554 : {
555 23408 : bool found = false;
556 : Relation catalogRelation;
557 : ScanKeyData key;
558 : SysScanDesc scan;
559 : HeapTuple inheritsTuple;
560 :
561 : /*
562 : * Find pg_inherits entries by inhrelid.
563 : */
564 23408 : catalogRelation = table_open(InheritsRelationId, RowExclusiveLock);
565 23408 : ScanKeyInit(&key,
566 : Anum_pg_inherits_inhrelid,
567 : BTEqualStrategyNumber, F_OIDEQ,
568 : ObjectIdGetDatum(inhrelid));
569 23408 : scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
570 : true, NULL, 1, &key);
571 :
572 26258 : while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
573 : {
574 : Oid parent;
575 :
576 : /* Compare inhparent if it was given, and do the actual deletion. */
577 2850 : parent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
578 2850 : if (!OidIsValid(inhparent) || parent == inhparent)
579 : {
580 : bool detach_pending;
581 :
582 2796 : detach_pending =
583 2796 : ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhdetachpending;
584 :
585 : /*
586 : * Raise error depending on state. This should only happen for
587 : * partitions, but we have no way to cross-check.
588 : */
589 2796 : if (detach_pending && !expect_detach_pending)
590 0 : ereport(ERROR,
591 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
592 : errmsg("cannot detach partition \"%s\"",
593 : childname ? childname : "unknown relation"),
594 : errdetail("The partition is being detached concurrently or has an unfinished detach."),
595 : errhint("Use ALTER TABLE ... DETACH PARTITION ... FINALIZE to complete the pending detach operation.")));
596 2796 : if (!detach_pending && expect_detach_pending)
597 0 : ereport(ERROR,
598 : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
599 : errmsg("cannot complete detaching partition \"%s\"",
600 : childname ? childname : "unknown relation"),
601 : errdetail("There's no pending concurrent detach.")));
602 :
603 2796 : CatalogTupleDelete(catalogRelation, &inheritsTuple->t_self);
604 2796 : found = true;
605 : }
606 : }
607 :
608 : /* Done */
609 23408 : systable_endscan(scan);
610 23408 : table_close(catalogRelation, RowExclusiveLock);
611 :
612 23408 : return found;
613 : }
614 :
615 : /*
616 : * Return whether the pg_inherits tuple for a partition has the "detach
617 : * pending" flag set.
618 : */
619 : bool
620 1356 : PartitionHasPendingDetach(Oid partoid)
621 : {
622 : Relation catalogRelation;
623 : ScanKeyData key;
624 : SysScanDesc scan;
625 : HeapTuple inheritsTuple;
626 :
627 : /* We don't have a good way to verify it is in fact a partition */
628 :
629 : /*
630 : * Find the pg_inherits entry by inhrelid. (There should only be one.)
631 : */
632 1356 : catalogRelation = table_open(InheritsRelationId, RowExclusiveLock);
633 1356 : ScanKeyInit(&key,
634 : Anum_pg_inherits_inhrelid,
635 : BTEqualStrategyNumber, F_OIDEQ,
636 : ObjectIdGetDatum(partoid));
637 1356 : scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
638 : true, NULL, 1, &key);
639 :
640 1356 : while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
641 : {
642 : bool detached;
643 :
644 1356 : detached =
645 1356 : ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhdetachpending;
646 :
647 : /* Done */
648 1356 : systable_endscan(scan);
649 1356 : table_close(catalogRelation, RowExclusiveLock);
650 :
651 1356 : return detached;
652 : }
653 :
654 0 : elog(ERROR, "relation %u is not a partition", partoid);
655 : return false; /* keep compiler quiet */
656 : }
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