1 /*-------------------------------------------------------------------------
4 * Routines to support inter-object dependencies.
7 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
11 * $PostgreSQL: pgsql/src/backend/catalog/dependency.c,v 1.36 2004/05/26 04:41:06 neilc Exp $
13 *-------------------------------------------------------------------------
17 #include "access/genam.h"
18 #include "access/heapam.h"
19 #include "catalog/catname.h"
20 #include "catalog/dependency.h"
21 #include "catalog/heap.h"
22 #include "catalog/index.h"
23 #include "catalog/indexing.h"
24 #include "catalog/namespace.h"
25 #include "catalog/pg_attrdef.h"
26 #include "catalog/pg_cast.h"
27 #include "catalog/pg_constraint.h"
28 #include "catalog/pg_conversion.h"
29 #include "catalog/pg_depend.h"
30 #include "catalog/pg_language.h"
31 #include "catalog/pg_opclass.h"
32 #include "catalog/pg_rewrite.h"
33 #include "catalog/pg_trigger.h"
34 #include "commands/comment.h"
35 #include "commands/defrem.h"
36 #include "commands/proclang.h"
37 #include "commands/schemacmds.h"
38 #include "commands/trigger.h"
39 #include "commands/typecmds.h"
40 #include "lib/stringinfo.h"
41 #include "miscadmin.h"
42 #include "optimizer/clauses.h"
43 #include "parser/parsetree.h"
44 #include "rewrite/rewriteRemove.h"
45 #include "utils/builtins.h"
46 #include "utils/fmgroids.h"
47 #include "utils/lsyscache.h"
48 #include "utils/syscache.h"
51 /* expansible list of ObjectAddresses */
54 ObjectAddress *refs; /* => palloc'd array */
55 int numrefs; /* current number of references */
56 int maxrefs; /* current size of palloc'd array */
59 /* for find_expr_references_walker */
62 ObjectAddresses addrs; /* addresses being accumulated */
63 List *rtables; /* list of rangetables to resolve Vars */
64 } find_expr_references_context;
68 * Because not all system catalogs have predetermined OIDs, we build a table
69 * mapping between ObjectClasses and OIDs. This is done at most once per
70 * backend run, to minimize lookup overhead.
72 static bool object_classes_initialized = false;
73 static Oid object_classes[MAX_OCLASS];
76 static void findAutoDeletableObjects(const ObjectAddress *object,
77 ObjectAddresses *oktodelete,
79 static bool recursiveDeletion(const ObjectAddress *object,
80 DropBehavior behavior,
82 const ObjectAddress *callingObject,
83 ObjectAddresses *oktodelete,
85 static bool deleteDependentObjects(const ObjectAddress *object,
86 const char *objDescription,
87 DropBehavior behavior,
89 ObjectAddresses *oktodelete,
91 static void doDeletion(const ObjectAddress *object);
92 static bool find_expr_references_walker(Node *node,
93 find_expr_references_context *context);
94 static void eliminate_duplicate_dependencies(ObjectAddresses *addrs);
95 static int object_address_comparator(const void *a, const void *b);
96 static void init_object_addresses(ObjectAddresses *addrs);
97 static void add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
98 ObjectAddresses *addrs);
99 static void add_exact_object_address(const ObjectAddress *object,
100 ObjectAddresses *addrs);
101 static bool object_address_present(const ObjectAddress *object,
102 ObjectAddresses *addrs);
103 static void term_object_addresses(ObjectAddresses *addrs);
104 static void init_object_classes(void);
105 static void getRelationDescription(StringInfo buffer, Oid relid);
109 * performDeletion: attempt to drop the specified object. If CASCADE
110 * behavior is specified, also drop any dependent objects (recursively).
111 * If RESTRICT behavior is specified, error out if there are any dependent
112 * objects, except for those that should be implicitly dropped anyway
113 * according to the dependency type.
115 * This is the outer control routine for all forms of DROP that drop objects
116 * that can participate in dependencies.
119 performDeletion(const ObjectAddress *object,
120 DropBehavior behavior)
122 char *objDescription;
124 ObjectAddresses oktodelete;
127 * Get object description for possible use in failure message. Must do
128 * this before deleting it ...
130 objDescription = getObjectDescription(object);
133 * We save some cycles by opening pg_depend just once and passing the
134 * Relation pointer down to all the recursive deletion steps.
136 depRel = heap_openr(DependRelationName, RowExclusiveLock);
139 * Construct a list of objects that are reachable by AUTO or INTERNAL
140 * dependencies from the target object. These should be deleted
141 * silently, even if the actual deletion pass first reaches one of
142 * them via a non-auto dependency.
144 init_object_addresses(&oktodelete);
146 findAutoDeletableObjects(object, &oktodelete, depRel);
148 if (!recursiveDeletion(object, behavior, NOTICE,
149 NULL, &oktodelete, depRel))
151 (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
152 errmsg("cannot drop %s because other objects depend on it",
154 errhint("Use DROP ... CASCADE to drop the dependent objects too.")));
156 term_object_addresses(&oktodelete);
158 heap_close(depRel, RowExclusiveLock);
160 pfree(objDescription);
165 * deleteWhatDependsOn: attempt to drop everything that depends on the
166 * specified object, though not the object itself. Behavior is always
169 * This is currently used only to clean out the contents of a schema
170 * (namespace): the passed object is a namespace. We normally want this
171 * to be done silently, so there's an option to suppress NOTICE messages.
174 deleteWhatDependsOn(const ObjectAddress *object,
177 char *objDescription;
179 ObjectAddresses oktodelete;
182 * Get object description for possible use in failure messages
184 objDescription = getObjectDescription(object);
187 * We save some cycles by opening pg_depend just once and passing the
188 * Relation pointer down to all the recursive deletion steps.
190 depRel = heap_openr(DependRelationName, RowExclusiveLock);
193 * Construct a list of objects that are reachable by AUTO or INTERNAL
194 * dependencies from the target object. These should be deleted
195 * silently, even if the actual deletion pass first reaches one of
196 * them via a non-auto dependency.
198 init_object_addresses(&oktodelete);
200 findAutoDeletableObjects(object, &oktodelete, depRel);
203 * Now invoke only step 2 of recursiveDeletion: just recurse to the
204 * stuff dependent on the given object.
206 if (!deleteDependentObjects(object, objDescription,
208 showNotices ? NOTICE : DEBUG2,
209 &oktodelete, depRel))
211 (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
212 errmsg("failed to drop all objects depending on %s",
216 * We do not need CommandCounterIncrement here, since if step 2 did
217 * anything then each recursive call will have ended with one.
220 term_object_addresses(&oktodelete);
222 heap_close(depRel, RowExclusiveLock);
224 pfree(objDescription);
229 * findAutoDeletableObjects: find all objects that are reachable by AUTO or
230 * INTERNAL dependency paths from the given object. Add them all to the
231 * oktodelete list. Note that the originally given object will also be
234 * depRel is the already-open pg_depend relation.
237 findAutoDeletableObjects(const ObjectAddress *object,
238 ObjectAddresses *oktodelete,
245 ObjectAddress otherObject;
248 * If this object is already in oktodelete, then we already visited
249 * it; don't do so again (this prevents infinite recursion if there's
250 * a loop in pg_depend). Otherwise, add it.
252 if (object_address_present(object, oktodelete))
254 add_exact_object_address(object, oktodelete);
257 * Scan pg_depend records that link to this object, showing the things
258 * that depend on it. For each one that is AUTO or INTERNAL, visit
259 * the referencing object.
261 * When dropping a whole object (subId = 0), find pg_depend records for
262 * its sub-objects too.
265 Anum_pg_depend_refclassid,
266 BTEqualStrategyNumber, F_OIDEQ,
267 ObjectIdGetDatum(object->classId));
269 Anum_pg_depend_refobjid,
270 BTEqualStrategyNumber, F_OIDEQ,
271 ObjectIdGetDatum(object->objectId));
272 if (object->objectSubId != 0)
275 Anum_pg_depend_refobjsubid,
276 BTEqualStrategyNumber, F_INT4EQ,
277 Int32GetDatum(object->objectSubId));
283 scan = systable_beginscan(depRel, DependReferenceIndex, true,
284 SnapshotNow, nkeys, key);
286 while (HeapTupleIsValid(tup = systable_getnext(scan)))
288 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
290 switch (foundDep->deptype)
292 case DEPENDENCY_NORMAL:
295 case DEPENDENCY_AUTO:
296 case DEPENDENCY_INTERNAL:
298 otherObject.classId = foundDep->classid;
299 otherObject.objectId = foundDep->objid;
300 otherObject.objectSubId = foundDep->objsubid;
301 findAutoDeletableObjects(&otherObject, oktodelete, depRel);
306 * For a PIN dependency we just ereport immediately; there
307 * won't be any others to examine, and we aren't ever
308 * going to let the user delete it.
311 (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
312 errmsg("cannot drop %s because it is required by the database system",
313 getObjectDescription(object))));
316 elog(ERROR, "unrecognized dependency type '%c' for %s",
317 foundDep->deptype, getObjectDescription(object));
322 systable_endscan(scan);
327 * recursiveDeletion: delete a single object for performDeletion, plus
328 * (recursively) anything that depends on it.
330 * Returns TRUE if successful, FALSE if not.
332 * callingObject is NULL at the outer level, else identifies the object that
333 * we recursed from (the reference object that someone else needs to delete).
335 * oktodelete is a list of objects verified deletable (ie, reachable by one
336 * or more AUTO or INTERNAL dependencies from the original target).
338 * depRel is the already-open pg_depend relation.
341 * In RESTRICT mode, we perform all the deletions anyway, but ereport a message
342 * and return FALSE if we find a restriction violation. performDeletion
343 * will then abort the transaction to nullify the deletions. We have to
344 * do it this way to (a) report all the direct and indirect dependencies
345 * while (b) not going into infinite recursion if there's a cycle.
347 * This is even more complex than one could wish, because it is possible for
348 * the same pair of objects to be related by both NORMAL and AUTO/INTERNAL
349 * dependencies. Also, we might have a situation where we've been asked to
350 * delete object A, and objects B and C both have AUTO dependencies on A,
351 * but B also has a NORMAL dependency on C. (Since any of these paths might
352 * be indirect, we can't prevent these scenarios, but must cope instead.)
353 * If we visit C before B then we would mistakenly decide that the B->C link
354 * should prevent the restricted drop from occurring. To handle this, we make
355 * a pre-scan to find all the objects that are auto-deletable from A. If we
356 * visit C first, but B is present in the oktodelete list, then we make no
357 * complaint but recurse to delete B anyway. (Note that in general we must
358 * delete B before deleting C; the drop routine for B may try to access C.)
360 * Note: in the case where the path to B is traversed first, we will not
361 * see the NORMAL dependency when we reach C, because of the pg_depend
362 * removals done in step 1. The oktodelete list is necessary just
363 * to make the behavior independent of the order in which pg_depend
364 * entries are visited.
367 recursiveDeletion(const ObjectAddress *object,
368 DropBehavior behavior,
370 const ObjectAddress *callingObject,
371 ObjectAddresses *oktodelete,
375 char *objDescription;
380 ObjectAddress otherObject;
381 ObjectAddress owningObject;
382 bool amOwned = false;
385 * Get object description for possible use in messages. Must do this
386 * before deleting it ...
388 objDescription = getObjectDescription(object);
391 * Step 1: find and remove pg_depend records that link from this
392 * object to others. We have to do this anyway, and doing it first
393 * ensures that we avoid infinite recursion in the case of cycles.
394 * Also, some dependency types require extra processing here.
396 * When dropping a whole object (subId = 0), remove all pg_depend records
397 * for its sub-objects too.
400 Anum_pg_depend_classid,
401 BTEqualStrategyNumber, F_OIDEQ,
402 ObjectIdGetDatum(object->classId));
404 Anum_pg_depend_objid,
405 BTEqualStrategyNumber, F_OIDEQ,
406 ObjectIdGetDatum(object->objectId));
407 if (object->objectSubId != 0)
410 Anum_pg_depend_objsubid,
411 BTEqualStrategyNumber, F_INT4EQ,
412 Int32GetDatum(object->objectSubId));
418 scan = systable_beginscan(depRel, DependDependerIndex, true,
419 SnapshotNow, nkeys, key);
421 while (HeapTupleIsValid(tup = systable_getnext(scan)))
423 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
425 otherObject.classId = foundDep->refclassid;
426 otherObject.objectId = foundDep->refobjid;
427 otherObject.objectSubId = foundDep->refobjsubid;
429 switch (foundDep->deptype)
431 case DEPENDENCY_NORMAL:
432 case DEPENDENCY_AUTO:
435 case DEPENDENCY_INTERNAL:
438 * This object is part of the internal implementation of
439 * another object. We have three cases:
441 * 1. At the outermost recursion level, disallow the DROP.
442 * (We just ereport here, rather than proceeding, since no
443 * other dependencies are likely to be interesting.)
445 if (callingObject == NULL)
447 char *otherObjDesc = getObjectDescription(&otherObject);
450 (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
451 errmsg("cannot drop %s because %s requires it",
452 objDescription, otherObjDesc),
453 errhint("You may drop %s instead.",
458 * 2. When recursing from the other end of this
459 * dependency, it's okay to continue with the deletion.
460 * This holds when recursing from a whole object that
461 * includes the nominal other end as a component, too.
463 if (callingObject->classId == otherObject.classId &&
464 callingObject->objectId == otherObject.objectId &&
465 (callingObject->objectSubId == otherObject.objectSubId ||
466 callingObject->objectSubId == 0))
470 * 3. When recursing from anyplace else, transform this
471 * deletion request into a delete of the other object.
472 * (This will be an error condition iff RESTRICT mode.) In
473 * this case we finish deleting my dependencies except for
474 * the INTERNAL link, which will be needed to cause the
475 * owning object to recurse back to me.
477 if (amOwned) /* shouldn't happen */
478 elog(ERROR, "multiple INTERNAL dependencies for %s",
480 owningObject = otherObject;
482 /* "continue" bypasses the simple_heap_delete call below */
487 * Should not happen; PIN dependencies should have zeroes
488 * in the depender fields...
490 elog(ERROR, "incorrect use of PIN dependency with %s",
494 elog(ERROR, "unrecognized dependency type '%c' for %s",
495 foundDep->deptype, objDescription);
499 simple_heap_delete(depRel, &tup->t_self);
502 systable_endscan(scan);
505 * CommandCounterIncrement here to ensure that preceding changes are
506 * all visible; in particular, that the above deletions of pg_depend
507 * entries are visible. That prevents infinite recursion in case of a
508 * dependency loop (which is perfectly legal).
510 CommandCounterIncrement();
513 * If we found we are owned by another object, ask it to delete itself
514 * instead of proceeding. Complain if RESTRICT mode, unless the other
515 * object is in oktodelete.
519 if (object_address_present(&owningObject, oktodelete))
521 (errmsg("drop auto-cascades to %s",
522 getObjectDescription(&owningObject))));
523 else if (behavior == DROP_RESTRICT)
526 (errmsg("%s depends on %s",
527 getObjectDescription(&owningObject),
533 (errmsg("drop cascades to %s",
534 getObjectDescription(&owningObject))));
536 if (!recursiveDeletion(&owningObject, behavior, msglevel,
537 object, oktodelete, depRel))
540 pfree(objDescription);
546 * Step 2: scan pg_depend records that link to this object, showing
547 * the things that depend on it. Recursively delete those things.
548 * Note it's important to delete the dependent objects before the
549 * referenced one, since the deletion routines might do things like
550 * try to update the pg_class record when deleting a check constraint.
552 if (!deleteDependentObjects(object, objDescription,
558 * We do not need CommandCounterIncrement here, since if step 2 did
559 * anything then each recursive call will have ended with one.
563 * Step 3: delete the object itself.
568 * Delete any comments associated with this object. (This is a
569 * convenient place to do it instead of having every object type know
572 DeleteComments(object->objectId, object->classId, object->objectSubId);
575 * CommandCounterIncrement here to ensure that preceding changes are
578 CommandCounterIncrement();
583 pfree(objDescription);
590 * deleteDependentObjects - find and delete objects that depend on 'object'
592 * Scan pg_depend records that link to the given object, showing
593 * the things that depend on it. Recursively delete those things. (We
594 * don't delete the pg_depend records here, as the recursive call will
595 * do that.) Note it's important to delete the dependent objects
596 * before the referenced one, since the deletion routines might do
597 * things like try to update the pg_class record when deleting a check
600 * When dropping a whole object (subId = 0), find pg_depend records for
601 * its sub-objects too.
603 * object: the object to find dependencies on
604 * objDescription: description of object (only used for error messages)
605 * behavior: desired drop behavior
606 * oktodelete: stuff that's AUTO-deletable
607 * depRel: already opened pg_depend relation
609 * Returns TRUE if all is well, false if any problem found.
611 * NOTE: because we are using SnapshotNow, if a recursive call deletes
612 * any pg_depend tuples that our scan hasn't yet visited, we will not
613 * see them as good when we do visit them. This is essential for
614 * correct behavior if there are multiple dependency paths between two
615 * objects --- else we might try to delete an already-deleted object.
618 deleteDependentObjects(const ObjectAddress *object,
619 const char *objDescription,
620 DropBehavior behavior,
622 ObjectAddresses *oktodelete,
630 ObjectAddress otherObject;
633 Anum_pg_depend_refclassid,
634 BTEqualStrategyNumber, F_OIDEQ,
635 ObjectIdGetDatum(object->classId));
637 Anum_pg_depend_refobjid,
638 BTEqualStrategyNumber, F_OIDEQ,
639 ObjectIdGetDatum(object->objectId));
640 if (object->objectSubId != 0)
643 Anum_pg_depend_refobjsubid,
644 BTEqualStrategyNumber, F_INT4EQ,
645 Int32GetDatum(object->objectSubId));
651 scan = systable_beginscan(depRel, DependReferenceIndex, true,
652 SnapshotNow, nkeys, key);
654 while (HeapTupleIsValid(tup = systable_getnext(scan)))
656 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
658 otherObject.classId = foundDep->classid;
659 otherObject.objectId = foundDep->objid;
660 otherObject.objectSubId = foundDep->objsubid;
662 switch (foundDep->deptype)
664 case DEPENDENCY_NORMAL:
667 * Perhaps there was another dependency path that would
668 * have allowed silent deletion of the otherObject, had we
669 * only taken that path first. In that case, act like this
672 if (object_address_present(&otherObject, oktodelete))
674 (errmsg("drop auto-cascades to %s",
675 getObjectDescription(&otherObject))));
676 else if (behavior == DROP_RESTRICT)
679 (errmsg("%s depends on %s",
680 getObjectDescription(&otherObject),
686 (errmsg("drop cascades to %s",
687 getObjectDescription(&otherObject))));
689 if (!recursiveDeletion(&otherObject, behavior, msglevel,
690 object, oktodelete, depRel))
693 case DEPENDENCY_AUTO:
694 case DEPENDENCY_INTERNAL:
697 * We propagate the DROP without complaint even in the
698 * RESTRICT case. (However, normal dependencies on the
699 * component object could still cause failure.)
702 (errmsg("drop auto-cascades to %s",
703 getObjectDescription(&otherObject))));
705 if (!recursiveDeletion(&otherObject, behavior, msglevel,
706 object, oktodelete, depRel))
712 * For a PIN dependency we just ereport immediately; there
713 * won't be any others to report.
716 (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
717 errmsg("cannot drop %s because it is required by the database system",
721 elog(ERROR, "unrecognized dependency type '%c' for %s",
722 foundDep->deptype, objDescription);
727 systable_endscan(scan);
734 * doDeletion: actually delete a single object
737 doDeletion(const ObjectAddress *object)
739 switch (getObjectClass(object))
743 char relKind = get_rel_relkind(object->objectId);
745 if (relKind == RELKIND_INDEX)
747 Assert(object->objectSubId == 0);
748 index_drop(object->objectId);
752 if (object->objectSubId != 0)
753 RemoveAttributeById(object->objectId,
754 object->objectSubId);
756 heap_drop_with_catalog(object->objectId);
762 RemoveFunctionById(object->objectId);
766 RemoveTypeById(object->objectId);
770 DropCastById(object->objectId);
773 case OCLASS_CONSTRAINT:
774 RemoveConstraintById(object->objectId);
777 case OCLASS_CONVERSION:
778 RemoveConversionById(object->objectId);
782 RemoveAttrDefaultById(object->objectId);
785 case OCLASS_LANGUAGE:
786 DropProceduralLanguageById(object->objectId);
789 case OCLASS_OPERATOR:
790 RemoveOperatorById(object->objectId);
794 RemoveOpClassById(object->objectId);
798 RemoveRewriteRuleById(object->objectId);
802 RemoveTriggerById(object->objectId);
806 RemoveSchemaById(object->objectId);
810 elog(ERROR, "unrecognized object class: %u",
816 * recordDependencyOnExpr - find expression dependencies
818 * This is used to find the dependencies of rules, constraint expressions,
821 * Given an expression or query in node-tree form, find all the objects
822 * it refers to (tables, columns, operators, functions, etc). Record
823 * a dependency of the specified type from the given depender object
824 * to each object mentioned in the expression.
826 * rtable is the rangetable to be used to interpret Vars with varlevelsup=0.
827 * It can be NIL if no such variables are expected.
829 * XXX is it important to create dependencies on the datatypes mentioned in
830 * the expression? In most cases this would be redundant (eg, a ref to an
831 * operator indirectly references its input and output datatypes), but I'm
832 * not quite convinced there are no cases where we need it.
835 recordDependencyOnExpr(const ObjectAddress *depender,
836 Node *expr, List *rtable,
837 DependencyType behavior)
839 find_expr_references_context context;
841 init_object_addresses(&context.addrs);
843 /* Set up interpretation for Vars at varlevelsup = 0 */
844 context.rtables = list_make1(rtable);
846 /* Scan the expression tree for referenceable objects */
847 find_expr_references_walker(expr, &context);
849 /* Remove any duplicates */
850 eliminate_duplicate_dependencies(&context.addrs);
853 recordMultipleDependencies(depender,
854 context.addrs.refs, context.addrs.numrefs,
857 term_object_addresses(&context.addrs);
861 * recordDependencyOnSingleRelExpr - find expression dependencies
863 * As above, but only one relation is expected to be referenced (with
864 * varno = 1 and varlevelsup = 0). Pass the relation OID instead of a
865 * range table. An additional frammish is that dependencies on that
866 * relation (or its component columns) will be marked with 'self_behavior',
867 * whereas 'behavior' is used for everything else.
870 recordDependencyOnSingleRelExpr(const ObjectAddress *depender,
871 Node *expr, Oid relId,
872 DependencyType behavior,
873 DependencyType self_behavior)
875 find_expr_references_context context;
878 init_object_addresses(&context.addrs);
880 /* We gin up a rather bogus rangetable list to handle Vars */
881 MemSet(&rte, 0, sizeof(rte));
882 rte.type = T_RangeTblEntry;
883 rte.rtekind = RTE_RELATION;
886 context.rtables = list_make1(list_make1(&rte));
888 /* Scan the expression tree for referenceable objects */
889 find_expr_references_walker(expr, &context);
891 /* Remove any duplicates */
892 eliminate_duplicate_dependencies(&context.addrs);
894 /* Separate self-dependencies if necessary */
895 if (behavior != self_behavior && context.addrs.numrefs > 0)
897 ObjectAddresses self_addrs;
898 ObjectAddress *outobj;
902 init_object_addresses(&self_addrs);
904 outobj = context.addrs.refs;
906 for (oldref = 0; oldref < context.addrs.numrefs; oldref++)
908 ObjectAddress *thisobj = context.addrs.refs + oldref;
910 if (thisobj->classId == RelOid_pg_class &&
911 thisobj->objectId == relId)
913 /* Move this ref into self_addrs */
914 add_object_address(OCLASS_CLASS, relId, thisobj->objectSubId,
919 /* Keep it in context.addrs */
920 outobj->classId = thisobj->classId;
921 outobj->objectId = thisobj->objectId;
922 outobj->objectSubId = thisobj->objectSubId;
927 context.addrs.numrefs = outrefs;
929 /* Record the self-dependencies */
930 recordMultipleDependencies(depender,
931 self_addrs.refs, self_addrs.numrefs,
934 term_object_addresses(&self_addrs);
937 /* Record the external dependencies */
938 recordMultipleDependencies(depender,
939 context.addrs.refs, context.addrs.numrefs,
942 term_object_addresses(&context.addrs);
946 * Recursively search an expression tree for object references.
948 * Note: we avoid creating references to columns of tables that participate
949 * in an SQL JOIN construct, but are not actually used anywhere in the query.
950 * To do so, we do not scan the joinaliasvars list of a join RTE while
951 * scanning the query rangetable, but instead scan each individual entry
952 * of the alias list when we find a reference to it.
955 find_expr_references_walker(Node *node,
956 find_expr_references_context *context)
962 Var *var = (Var *) node;
966 /* Find matching rtable entry, or complain if not found */
967 if (var->varlevelsup >= list_length(context->rtables))
968 elog(ERROR, "invalid varlevelsup %d", var->varlevelsup);
969 rtable = (List *) list_nth(context->rtables, var->varlevelsup);
970 if (var->varno <= 0 || var->varno > list_length(rtable))
971 elog(ERROR, "invalid varno %d", var->varno);
972 rte = rt_fetch(var->varno, rtable);
973 if (rte->rtekind == RTE_RELATION)
975 /* If it's a plain relation, reference this column */
976 /* NB: this code works for whole-row Var with attno 0, too */
977 add_object_address(OCLASS_CLASS, rte->relid, var->varattno,
980 else if (rte->rtekind == RTE_JOIN)
982 /* Scan join output column to add references to join inputs */
985 /* We must make the context appropriate for join's level */
986 save_rtables = context->rtables;
987 context->rtables = list_copy_tail(context->rtables,
989 if (var->varattno <= 0 ||
990 var->varattno > list_length(rte->joinaliasvars))
991 elog(ERROR, "invalid varattno %d", var->varattno);
992 find_expr_references_walker((Node *) list_nth(rte->joinaliasvars,
995 list_free(context->rtables);
996 context->rtables = save_rtables;
1000 if (IsA(node, FuncExpr))
1002 FuncExpr *funcexpr = (FuncExpr *) node;
1004 add_object_address(OCLASS_PROC, funcexpr->funcid, 0,
1006 /* fall through to examine arguments */
1008 if (IsA(node, OpExpr))
1010 OpExpr *opexpr = (OpExpr *) node;
1012 add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
1014 /* fall through to examine arguments */
1016 if (IsA(node, DistinctExpr))
1018 DistinctExpr *distinctexpr = (DistinctExpr *) node;
1020 add_object_address(OCLASS_OPERATOR, distinctexpr->opno, 0,
1022 /* fall through to examine arguments */
1024 if (IsA(node, ScalarArrayOpExpr))
1026 ScalarArrayOpExpr *opexpr = (ScalarArrayOpExpr *) node;
1028 add_object_address(OCLASS_OPERATOR, opexpr->opno, 0,
1030 /* fall through to examine arguments */
1032 if (IsA(node, NullIfExpr))
1034 NullIfExpr *nullifexpr = (NullIfExpr *) node;
1036 add_object_address(OCLASS_OPERATOR, nullifexpr->opno, 0,
1038 /* fall through to examine arguments */
1040 if (IsA(node, Aggref))
1042 Aggref *aggref = (Aggref *) node;
1044 add_object_address(OCLASS_PROC, aggref->aggfnoid, 0,
1046 /* fall through to examine arguments */
1048 if (IsA(node, SubLink))
1050 SubLink *sublink = (SubLink *) node;
1053 foreach(opid, sublink->operOids)
1055 add_object_address(OCLASS_OPERATOR, lfirst_oid(opid), 0,
1058 /* fall through to examine arguments */
1060 if (is_subplan(node))
1062 /* Extra work needed here if we ever need this case */
1063 elog(ERROR, "already-planned subqueries not supported");
1065 if (IsA(node, Query))
1067 /* Recurse into RTE subquery or not-yet-planned sublink subquery */
1068 Query *query = (Query *) node;
1073 * Add whole-relation refs for each plain relation mentioned in
1074 * the subquery's rtable. (Note: query_tree_walker takes care of
1075 * recursing into RTE_FUNCTION and RTE_SUBQUERY RTEs, so no need
1076 * to do that here. But keep it from looking at join alias
1079 foreach(rtable, query->rtable)
1081 RangeTblEntry *rte = (RangeTblEntry *) lfirst(rtable);
1083 if (rte->rtekind == RTE_RELATION)
1084 add_object_address(OCLASS_CLASS, rte->relid, 0,
1088 /* Examine substructure of query */
1089 context->rtables = lcons(query->rtable, context->rtables);
1090 result = query_tree_walker(query,
1091 find_expr_references_walker,
1093 QTW_IGNORE_JOINALIASES);
1094 context->rtables = list_delete_first(context->rtables);
1097 return expression_tree_walker(node, find_expr_references_walker,
1102 * Given an array of dependency references, eliminate any duplicates.
1105 eliminate_duplicate_dependencies(ObjectAddresses *addrs)
1107 ObjectAddress *priorobj;
1111 if (addrs->numrefs <= 1)
1112 return; /* nothing to do */
1114 /* Sort the refs so that duplicates are adjacent */
1115 qsort((void *) addrs->refs, addrs->numrefs, sizeof(ObjectAddress),
1116 object_address_comparator);
1119 priorobj = addrs->refs;
1121 for (oldref = 1; oldref < addrs->numrefs; oldref++)
1123 ObjectAddress *thisobj = addrs->refs + oldref;
1125 if (priorobj->classId == thisobj->classId &&
1126 priorobj->objectId == thisobj->objectId)
1128 if (priorobj->objectSubId == thisobj->objectSubId)
1129 continue; /* identical, so drop thisobj */
1132 * If we have a whole-object reference and a reference to a
1133 * part of the same object, we don't need the whole-object
1134 * reference (for example, we don't need to reference both
1135 * table foo and column foo.bar). The whole-object reference
1136 * will always appear first in the sorted list.
1138 if (priorobj->objectSubId == 0)
1140 /* replace whole ref with partial */
1141 priorobj->objectSubId = thisobj->objectSubId;
1145 /* Not identical, so add thisobj to output set */
1147 priorobj->classId = thisobj->classId;
1148 priorobj->objectId = thisobj->objectId;
1149 priorobj->objectSubId = thisobj->objectSubId;
1153 addrs->numrefs = newrefs;
1157 * qsort comparator for ObjectAddress items
1160 object_address_comparator(const void *a, const void *b)
1162 const ObjectAddress *obja = (const ObjectAddress *) a;
1163 const ObjectAddress *objb = (const ObjectAddress *) b;
1165 if (obja->classId < objb->classId)
1167 if (obja->classId > objb->classId)
1169 if (obja->objectId < objb->objectId)
1171 if (obja->objectId > objb->objectId)
1175 * We sort the subId as an unsigned int so that 0 will come first. See
1176 * logic in eliminate_duplicate_dependencies.
1178 if ((unsigned int) obja->objectSubId < (unsigned int) objb->objectSubId)
1180 if ((unsigned int) obja->objectSubId > (unsigned int) objb->objectSubId)
1186 * Routines for handling an expansible array of ObjectAddress items.
1188 * init_object_addresses: initialize an ObjectAddresses array.
1191 init_object_addresses(ObjectAddresses *addrs)
1193 /* Initialize array to empty */
1195 addrs->maxrefs = 32; /* arbitrary initial array size */
1196 addrs->refs = (ObjectAddress *)
1197 palloc(addrs->maxrefs * sizeof(ObjectAddress));
1199 /* Initialize object_classes[] if not done yet */
1200 /* This will be needed by add_object_address() */
1201 if (!object_classes_initialized)
1202 init_object_classes();
1206 * Add an entry to an ObjectAddresses array.
1208 * It is convenient to specify the class by ObjectClass rather than directly
1212 add_object_address(ObjectClass oclass, Oid objectId, int32 subId,
1213 ObjectAddresses *addrs)
1215 ObjectAddress *item;
1217 /* enlarge array if needed */
1218 if (addrs->numrefs >= addrs->maxrefs)
1220 addrs->maxrefs *= 2;
1221 addrs->refs = (ObjectAddress *)
1222 repalloc(addrs->refs, addrs->maxrefs * sizeof(ObjectAddress));
1224 /* record this item */
1225 item = addrs->refs + addrs->numrefs;
1226 item->classId = object_classes[oclass];
1227 item->objectId = objectId;
1228 item->objectSubId = subId;
1233 * Add an entry to an ObjectAddresses array.
1235 * As above, but specify entry exactly.
1238 add_exact_object_address(const ObjectAddress *object,
1239 ObjectAddresses *addrs)
1241 ObjectAddress *item;
1243 /* enlarge array if needed */
1244 if (addrs->numrefs >= addrs->maxrefs)
1246 addrs->maxrefs *= 2;
1247 addrs->refs = (ObjectAddress *)
1248 repalloc(addrs->refs, addrs->maxrefs * sizeof(ObjectAddress));
1250 /* record this item */
1251 item = addrs->refs + addrs->numrefs;
1257 * Test whether an object is present in an ObjectAddresses array.
1259 * We return "true" if object is a subobject of something in the array, too.
1262 object_address_present(const ObjectAddress *object,
1263 ObjectAddresses *addrs)
1267 for (i = addrs->numrefs - 1; i >= 0; i--)
1269 ObjectAddress *thisobj = addrs->refs + i;
1271 if (object->classId == thisobj->classId &&
1272 object->objectId == thisobj->objectId)
1274 if (object->objectSubId == thisobj->objectSubId ||
1275 thisobj->objectSubId == 0)
1284 * Clean up when done with an ObjectAddresses array.
1287 term_object_addresses(ObjectAddresses *addrs)
1293 * Initialize the object_classes[] table.
1295 * Although some of these OIDs aren't compile-time constants, they surely
1296 * shouldn't change during a backend's run. So, we look them up the
1297 * first time through and then cache them.
1300 init_object_classes(void)
1302 object_classes[OCLASS_CLASS] = RelOid_pg_class;
1303 object_classes[OCLASS_PROC] = RelOid_pg_proc;
1304 object_classes[OCLASS_TYPE] = RelOid_pg_type;
1305 object_classes[OCLASS_CAST] = get_system_catalog_relid(CastRelationName);
1306 object_classes[OCLASS_CONSTRAINT] = get_system_catalog_relid(ConstraintRelationName);
1307 object_classes[OCLASS_CONVERSION] = get_system_catalog_relid(ConversionRelationName);
1308 object_classes[OCLASS_DEFAULT] = get_system_catalog_relid(AttrDefaultRelationName);
1309 object_classes[OCLASS_LANGUAGE] = get_system_catalog_relid(LanguageRelationName);
1310 object_classes[OCLASS_OPERATOR] = get_system_catalog_relid(OperatorRelationName);
1311 object_classes[OCLASS_OPCLASS] = get_system_catalog_relid(OperatorClassRelationName);
1312 object_classes[OCLASS_REWRITE] = get_system_catalog_relid(RewriteRelationName);
1313 object_classes[OCLASS_TRIGGER] = get_system_catalog_relid(TriggerRelationName);
1314 object_classes[OCLASS_SCHEMA] = get_system_catalog_relid(NamespaceRelationName);
1315 object_classes_initialized = true;
1319 * Determine the class of a given object identified by objectAddress.
1321 * This function is needed just because some of the system catalogs do
1322 * not have hardwired-at-compile-time OIDs.
1325 getObjectClass(const ObjectAddress *object)
1327 /* Easy for the bootstrapped catalogs... */
1328 switch (object->classId)
1330 case RelOid_pg_class:
1331 /* caller must check objectSubId */
1332 return OCLASS_CLASS;
1334 case RelOid_pg_proc:
1335 Assert(object->objectSubId == 0);
1338 case RelOid_pg_type:
1339 Assert(object->objectSubId == 0);
1344 * Handle cases where catalog's OID is not hardwired.
1346 if (!object_classes_initialized)
1347 init_object_classes();
1349 if (object->classId == object_classes[OCLASS_CAST])
1351 Assert(object->objectSubId == 0);
1354 if (object->classId == object_classes[OCLASS_CONSTRAINT])
1356 Assert(object->objectSubId == 0);
1357 return OCLASS_CONSTRAINT;
1359 if (object->classId == object_classes[OCLASS_CONVERSION])
1361 Assert(object->objectSubId == 0);
1362 return OCLASS_CONVERSION;
1364 if (object->classId == object_classes[OCLASS_DEFAULT])
1366 Assert(object->objectSubId == 0);
1367 return OCLASS_DEFAULT;
1369 if (object->classId == object_classes[OCLASS_LANGUAGE])
1371 Assert(object->objectSubId == 0);
1372 return OCLASS_LANGUAGE;
1374 if (object->classId == object_classes[OCLASS_OPERATOR])
1376 Assert(object->objectSubId == 0);
1377 return OCLASS_OPERATOR;
1379 if (object->classId == object_classes[OCLASS_OPCLASS])
1381 Assert(object->objectSubId == 0);
1382 return OCLASS_OPCLASS;
1384 if (object->classId == object_classes[OCLASS_REWRITE])
1386 Assert(object->objectSubId == 0);
1387 return OCLASS_REWRITE;
1389 if (object->classId == object_classes[OCLASS_TRIGGER])
1391 Assert(object->objectSubId == 0);
1392 return OCLASS_TRIGGER;
1394 if (object->classId == object_classes[OCLASS_SCHEMA])
1396 Assert(object->objectSubId == 0);
1397 return OCLASS_SCHEMA;
1400 elog(ERROR, "unrecognized object class: %u", object->classId);
1401 return OCLASS_CLASS; /* keep compiler quiet */
1405 * getObjectDescription: build an object description for messages
1407 * The result is a palloc'd string.
1410 getObjectDescription(const ObjectAddress *object)
1412 StringInfoData buffer;
1414 initStringInfo(&buffer);
1416 switch (getObjectClass(object))
1419 getRelationDescription(&buffer, object->objectId);
1420 if (object->objectSubId != 0)
1421 appendStringInfo(&buffer, gettext(" column %s"),
1422 get_relid_attribute_name(object->objectId,
1423 object->objectSubId));
1427 appendStringInfo(&buffer, gettext("function %s"),
1428 format_procedure(object->objectId));
1432 appendStringInfo(&buffer, gettext("type %s"),
1433 format_type_be(object->objectId));
1439 ScanKeyData skey[1];
1442 Form_pg_cast castForm;
1444 castDesc = heap_openr(CastRelationName, AccessShareLock);
1446 ScanKeyInit(&skey[0],
1447 ObjectIdAttributeNumber,
1448 BTEqualStrategyNumber, F_OIDEQ,
1449 ObjectIdGetDatum(object->objectId));
1451 rcscan = systable_beginscan(castDesc, CastOidIndex, true,
1452 SnapshotNow, 1, skey);
1454 tup = systable_getnext(rcscan);
1456 if (!HeapTupleIsValid(tup))
1457 elog(ERROR, "could not find tuple for cast %u",
1460 castForm = (Form_pg_cast) GETSTRUCT(tup);
1462 appendStringInfo(&buffer, gettext("cast from %s to %s"),
1463 format_type_be(castForm->castsource),
1464 format_type_be(castForm->casttarget));
1466 systable_endscan(rcscan);
1467 heap_close(castDesc, AccessShareLock);
1471 case OCLASS_CONSTRAINT:
1474 ScanKeyData skey[1];
1477 Form_pg_constraint con;
1479 conDesc = heap_openr(ConstraintRelationName, AccessShareLock);
1481 ScanKeyInit(&skey[0],
1482 ObjectIdAttributeNumber,
1483 BTEqualStrategyNumber, F_OIDEQ,
1484 ObjectIdGetDatum(object->objectId));
1486 rcscan = systable_beginscan(conDesc, ConstraintOidIndex, true,
1487 SnapshotNow, 1, skey);
1489 tup = systable_getnext(rcscan);
1491 if (!HeapTupleIsValid(tup))
1492 elog(ERROR, "could not find tuple for constraint %u",
1495 con = (Form_pg_constraint) GETSTRUCT(tup);
1497 if (OidIsValid(con->conrelid))
1499 appendStringInfo(&buffer, gettext("constraint %s on "),
1500 NameStr(con->conname));
1501 getRelationDescription(&buffer, con->conrelid);
1505 appendStringInfo(&buffer, gettext("constraint %s"),
1506 NameStr(con->conname));
1509 systable_endscan(rcscan);
1510 heap_close(conDesc, AccessShareLock);
1514 case OCLASS_CONVERSION:
1518 conTup = SearchSysCache(CONOID,
1519 ObjectIdGetDatum(object->objectId),
1521 if (!HeapTupleIsValid(conTup))
1522 elog(ERROR, "cache lookup failed for conversion %u",
1524 appendStringInfo(&buffer, gettext("conversion %s"),
1525 NameStr(((Form_pg_conversion) GETSTRUCT(conTup))->conname));
1526 ReleaseSysCache(conTup);
1530 case OCLASS_DEFAULT:
1532 Relation attrdefDesc;
1533 ScanKeyData skey[1];
1536 Form_pg_attrdef attrdef;
1537 ObjectAddress colobject;
1539 attrdefDesc = heap_openr(AttrDefaultRelationName, AccessShareLock);
1541 ScanKeyInit(&skey[0],
1542 ObjectIdAttributeNumber,
1543 BTEqualStrategyNumber, F_OIDEQ,
1544 ObjectIdGetDatum(object->objectId));
1546 adscan = systable_beginscan(attrdefDesc, AttrDefaultOidIndex,
1547 true, SnapshotNow, 1, skey);
1549 tup = systable_getnext(adscan);
1551 if (!HeapTupleIsValid(tup))
1552 elog(ERROR, "could not find tuple for attrdef %u",
1555 attrdef = (Form_pg_attrdef) GETSTRUCT(tup);
1557 colobject.classId = RelOid_pg_class;
1558 colobject.objectId = attrdef->adrelid;
1559 colobject.objectSubId = attrdef->adnum;
1561 appendStringInfo(&buffer, gettext("default for %s"),
1562 getObjectDescription(&colobject));
1564 systable_endscan(adscan);
1565 heap_close(attrdefDesc, AccessShareLock);
1569 case OCLASS_LANGUAGE:
1573 langTup = SearchSysCache(LANGOID,
1574 ObjectIdGetDatum(object->objectId),
1576 if (!HeapTupleIsValid(langTup))
1577 elog(ERROR, "cache lookup failed for language %u",
1579 appendStringInfo(&buffer, gettext("language %s"),
1580 NameStr(((Form_pg_language) GETSTRUCT(langTup))->lanname));
1581 ReleaseSysCache(langTup);
1585 case OCLASS_OPERATOR:
1586 appendStringInfo(&buffer, gettext("operator %s"),
1587 format_operator(object->objectId));
1590 case OCLASS_OPCLASS:
1593 Form_pg_opclass opcForm;
1598 opcTup = SearchSysCache(CLAOID,
1599 ObjectIdGetDatum(object->objectId),
1601 if (!HeapTupleIsValid(opcTup))
1602 elog(ERROR, "cache lookup failed for opclass %u",
1604 opcForm = (Form_pg_opclass) GETSTRUCT(opcTup);
1606 amTup = SearchSysCache(AMOID,
1607 ObjectIdGetDatum(opcForm->opcamid),
1609 if (!HeapTupleIsValid(amTup))
1610 elog(ERROR, "cache lookup failed for access method %u",
1612 amForm = (Form_pg_am) GETSTRUCT(amTup);
1614 /* Qualify the name if not visible in search path */
1615 if (OpclassIsVisible(object->objectId))
1618 nspname = get_namespace_name(opcForm->opcnamespace);
1620 appendStringInfo(&buffer, gettext("operator class %s for %s"),
1621 quote_qualified_identifier(nspname,
1622 NameStr(opcForm->opcname)),
1623 NameStr(amForm->amname));
1625 ReleaseSysCache(amTup);
1626 ReleaseSysCache(opcTup);
1630 case OCLASS_REWRITE:
1633 ScanKeyData skey[1];
1636 Form_pg_rewrite rule;
1638 ruleDesc = heap_openr(RewriteRelationName, AccessShareLock);
1640 ScanKeyInit(&skey[0],
1641 ObjectIdAttributeNumber,
1642 BTEqualStrategyNumber, F_OIDEQ,
1643 ObjectIdGetDatum(object->objectId));
1645 rcscan = systable_beginscan(ruleDesc, RewriteOidIndex, true,
1646 SnapshotNow, 1, skey);
1648 tup = systable_getnext(rcscan);
1650 if (!HeapTupleIsValid(tup))
1651 elog(ERROR, "could not find tuple for rule %u",
1654 rule = (Form_pg_rewrite) GETSTRUCT(tup);
1656 appendStringInfo(&buffer, gettext("rule %s on "),
1657 NameStr(rule->rulename));
1658 getRelationDescription(&buffer, rule->ev_class);
1660 systable_endscan(rcscan);
1661 heap_close(ruleDesc, AccessShareLock);
1665 case OCLASS_TRIGGER:
1668 ScanKeyData skey[1];
1671 Form_pg_trigger trig;
1673 trigDesc = heap_openr(TriggerRelationName, AccessShareLock);
1675 ScanKeyInit(&skey[0],
1676 ObjectIdAttributeNumber,
1677 BTEqualStrategyNumber, F_OIDEQ,
1678 ObjectIdGetDatum(object->objectId));
1680 tgscan = systable_beginscan(trigDesc, TriggerOidIndex, true,
1681 SnapshotNow, 1, skey);
1683 tup = systable_getnext(tgscan);
1685 if (!HeapTupleIsValid(tup))
1686 elog(ERROR, "could not find tuple for trigger %u",
1689 trig = (Form_pg_trigger) GETSTRUCT(tup);
1691 appendStringInfo(&buffer, gettext("trigger %s on "),
1692 NameStr(trig->tgname));
1693 getRelationDescription(&buffer, trig->tgrelid);
1695 systable_endscan(tgscan);
1696 heap_close(trigDesc, AccessShareLock);
1704 nspname = get_namespace_name(object->objectId);
1706 elog(ERROR, "cache lookup failed for namespace %u",
1708 appendStringInfo(&buffer, gettext("schema %s"), nspname);
1713 appendStringInfo(&buffer, "unrecognized object %u %u %d",
1716 object->objectSubId);
1724 * subroutine for getObjectDescription: describe a relation
1727 getRelationDescription(StringInfo buffer, Oid relid)
1730 Form_pg_class relForm;
1734 relTup = SearchSysCache(RELOID,
1735 ObjectIdGetDatum(relid),
1737 if (!HeapTupleIsValid(relTup))
1738 elog(ERROR, "cache lookup failed for relation %u", relid);
1739 relForm = (Form_pg_class) GETSTRUCT(relTup);
1741 /* Qualify the name if not visible in search path */
1742 if (RelationIsVisible(relid))
1745 nspname = get_namespace_name(relForm->relnamespace);
1747 relname = quote_qualified_identifier(nspname, NameStr(relForm->relname));
1749 switch (relForm->relkind)
1751 case RELKIND_RELATION:
1752 appendStringInfo(buffer, gettext("table %s"),
1756 appendStringInfo(buffer, gettext("index %s"),
1759 case RELKIND_SPECIAL:
1760 appendStringInfo(buffer, gettext("special system relation %s"),
1763 case RELKIND_SEQUENCE:
1764 appendStringInfo(buffer, gettext("sequence %s"),
1767 case RELKIND_UNCATALOGED:
1768 appendStringInfo(buffer, gettext("uncataloged table %s"),
1771 case RELKIND_TOASTVALUE:
1772 appendStringInfo(buffer, gettext("toast table %s"),
1776 appendStringInfo(buffer, gettext("view %s"),
1779 case RELKIND_COMPOSITE_TYPE:
1780 appendStringInfo(buffer, gettext("composite type %s"),
1784 /* shouldn't get here */
1785 appendStringInfo(buffer, gettext("relation %s"),
1790 ReleaseSysCache(relTup);