diff options
Diffstat (limited to 'src/backend/commands/trigger.c')
| -rw-r--r-- | src/backend/commands/trigger.c | 345 |
1 files changed, 199 insertions, 146 deletions
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c index ead586a2f21..e585f1517ad 100644 --- a/src/backend/commands/trigger.c +++ b/src/backend/commands/trigger.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.258 2010/01/02 16:57:38 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.259 2010/01/17 22:56:21 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -93,27 +93,27 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo, * constraintOid, if nonzero, says that this trigger is being created * internally to implement that constraint. A suitable pg_depend entry will * be made to link the trigger to that constraint. constraintOid is zero when - * executing a user-entered CREATE TRIGGER command. + * executing a user-entered CREATE TRIGGER command. (For CREATE CONSTRAINT + * TRIGGER, we build a pg_constraint entry internally.) * * indexOid, if nonzero, is the OID of an index associated with the constraint. * We do nothing with this except store it into pg_trigger.tgconstrindid. * - * prefix is NULL for user-created triggers. For internally generated - * constraint triggers, it is a prefix string to use in building the - * trigger name. (stmt->trigname is the constraint name in such cases.) + * If isInternal is true then this is an internally-generated trigger. + * This argument sets the tgisinternal field of the pg_trigger entry, and + * if TRUE causes us to modify the given trigger name to ensure uniqueness. * - * If checkPermissions is true we require ACL_TRIGGER permissions on the - * relation. If not, the caller already checked permissions. (This is - * currently redundant with constraintOid being zero, but it's clearer to - * have a separate argument.) + * When isInternal is not true we require ACL_TRIGGER permissions on the + * relation. For internal triggers the caller must apply any required + * permission checks. * * Note: can return InvalidOid if we decided to not create a trigger at all, * but a foreign-key constraint. This is a kluge for backwards compatibility. */ Oid CreateTrigger(CreateTrigStmt *stmt, const char *queryString, - Oid constraintOid, Oid indexOid, const char *prefix, - bool checkPermissions) + Oid constraintOid, Oid indexOid, + bool isInternal) { int16 tgtype; int ncolumns; @@ -135,9 +135,8 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, Oid funcoid; Oid funcrettype; Oid trigoid; - char constrtrigname[NAMEDATALEN]; + char internaltrigname[NAMEDATALEN]; char *trigname; - char *constrname; Oid constrrelid = InvalidOid; ObjectAddress myself, referenced; @@ -160,7 +159,7 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, constrrelid = RangeVarGetRelid(stmt->constrrel, false); /* permission checks */ - if (checkPermissions) + if (!isInternal) { aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(), ACL_TRIGGER); @@ -338,7 +337,7 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, * convert this legacy representation into a regular foreign key * constraint. Ugly, but necessary for loading old dump files. */ - if (stmt->isconstraint && !OidIsValid(constraintOid) && + if (stmt->isconstraint && !isInternal && list_length(stmt->args) >= 6 && (list_length(stmt->args) % 2) == 0 && RI_FKey_trigger_type(funcoid) != RI_TRIGGER_NONE) @@ -352,6 +351,41 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, } /* + * If it's a user-entered CREATE CONSTRAINT TRIGGER command, make a + * corresponding pg_constraint entry. + */ + if (stmt->isconstraint && !OidIsValid(constraintOid)) + { + /* Internal callers should have made their own constraints */ + Assert(!isInternal); + constraintOid = CreateConstraintEntry(stmt->trigname, + RelationGetNamespace(rel), + CONSTRAINT_TRIGGER, + stmt->deferrable, + stmt->initdeferred, + RelationGetRelid(rel), + NULL, /* no conkey */ + 0, + InvalidOid, /* no domain */ + InvalidOid, /* no index */ + InvalidOid, /* no foreign key */ + NULL, + NULL, + NULL, + NULL, + 0, + ' ', + ' ', + ' ', + NULL, /* no exclusion */ + NULL, /* no check constraint */ + NULL, + NULL, + true, /* islocal */ + 0); /* inhcount */ + } + + /* * Generate the trigger's OID now, so that we can use it in the name if * needed. */ @@ -360,55 +394,52 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, trigoid = GetNewOid(tgrel); /* - * If trigger is for a constraint, stmt->trigname is the constraint - * name; save that and build a unique trigger name based on the supplied - * prefix, to avoid collisions with user-selected trigger names. + * If trigger is internally generated, modify the provided trigger name + * to ensure uniqueness by appending the trigger OID. (Callers will + * usually supply a simple constant trigger name in these cases.) */ - if (prefix != NULL) + if (isInternal) { - snprintf(constrtrigname, sizeof(constrtrigname), - "%s_%u", prefix, trigoid); - trigname = constrtrigname; - constrname = stmt->trigname; - } - else if (stmt->isconstraint) - { - /* user constraint trigger: trigger name is also constraint name */ - trigname = stmt->trigname; - constrname = stmt->trigname; + snprintf(internaltrigname, sizeof(internaltrigname), + "%s_%u", stmt->trigname, trigoid); + trigname = internaltrigname; } else { - /* regular trigger: use empty constraint name */ + /* user-defined trigger; use the specified trigger name as-is */ trigname = stmt->trigname; - constrname = ""; } /* * Scan pg_trigger for existing triggers on relation. We do this only to * give a nice error message if there's already a trigger of the same * name. (The unique index on tgrelid/tgname would complain anyway.) + * We can skip this for internally generated triggers, since the name + * modification above should be sufficient. * * NOTE that this is cool only because we have AccessExclusiveLock on the * relation, so the trigger set won't be changing underneath us. */ - ScanKeyInit(&key, - Anum_pg_trigger_tgrelid, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(RelationGetRelid(rel))); - tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true, - SnapshotNow, 1, &key); - while (HeapTupleIsValid(tuple = systable_getnext(tgscan))) + if (!isInternal) { - Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); + ScanKeyInit(&key, + Anum_pg_trigger_tgrelid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(RelationGetRelid(rel))); + tgscan = systable_beginscan(tgrel, TriggerRelidNameIndexId, true, + SnapshotNow, 1, &key); + while (HeapTupleIsValid(tuple = systable_getnext(tgscan))) + { + Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); - if (namestrcmp(&(pg_trigger->tgname), trigname) == 0) - ereport(ERROR, - (errcode(ERRCODE_DUPLICATE_OBJECT), - errmsg("trigger \"%s\" for relation \"%s\" already exists", - trigname, stmt->relation->relname))); + if (namestrcmp(&(pg_trigger->tgname), trigname) == 0) + ereport(ERROR, + (errcode(ERRCODE_DUPLICATE_OBJECT), + errmsg("trigger \"%s\" for relation \"%s\" already exists", + trigname, stmt->relation->relname))); + } + systable_endscan(tgscan); } - systable_endscan(tgscan); /* * Build the new pg_trigger tuple. @@ -421,9 +452,7 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, values[Anum_pg_trigger_tgfoid - 1] = ObjectIdGetDatum(funcoid); values[Anum_pg_trigger_tgtype - 1] = Int16GetDatum(tgtype); values[Anum_pg_trigger_tgenabled - 1] = CharGetDatum(TRIGGER_FIRES_ON_ORIGIN); - values[Anum_pg_trigger_tgisconstraint - 1] = BoolGetDatum(stmt->isconstraint); - values[Anum_pg_trigger_tgconstrname - 1] = DirectFunctionCall1(namein, - CStringGetDatum(constrname)); + values[Anum_pg_trigger_tgisinternal - 1] = BoolGetDatum(isInternal); values[Anum_pg_trigger_tgconstrrelid - 1] = ObjectIdGetDatum(constrrelid); values[Anum_pg_trigger_tgconstrindid - 1] = ObjectIdGetDatum(indexOid); values[Anum_pg_trigger_tgconstraint - 1] = ObjectIdGetDatum(constraintOid); @@ -580,12 +609,13 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, referenced.objectSubId = 0; recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL); - if (OidIsValid(constraintOid)) + if (isInternal && OidIsValid(constraintOid)) { /* - * It's for a constraint, so make it an internal dependency of the - * constraint. We can skip depending on the relations, as there'll be - * an indirect dependency via the constraint. + * Internally-generated trigger for a constraint, so make it an + * internal dependency of the constraint. We can skip depending on + * the relation(s), as there'll be an indirect dependency via the + * constraint. */ referenced.classId = ConstraintRelationId; referenced.objectId = constraintOid; @@ -595,7 +625,7 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, else { /* - * Regular CREATE TRIGGER, so place dependencies. We make trigger be + * User CREATE TRIGGER, so place dependencies. We make trigger be * auto-dropped if its relation is dropped or if the FK relation is * dropped. (Auto drop is compatible with our pre-7.3 behavior.) */ @@ -612,6 +642,17 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString, } /* Not possible to have an index dependency in this case */ Assert(!OidIsValid(indexOid)); + /* + * If it's a user-specified constraint trigger, make the constraint + * internally dependent on the trigger instead of vice versa. + */ + if (OidIsValid(constraintOid)) + { + referenced.classId = ConstraintRelationId; + referenced.objectId = constraintOid; + referenced.objectSubId = 0; + recordDependencyOn(&referenced, &myself, DEPENDENCY_INTERNAL); + } } /* If column-specific trigger, add normal dependencies on columns */ @@ -1221,7 +1262,7 @@ EnableDisableTrigger(Relation rel, const char *tgname, { Form_pg_trigger oldtrig = (Form_pg_trigger) GETSTRUCT(tuple); - if (OidIsValid(oldtrig->tgconstraint)) + if (oldtrig->tgisinternal) { /* system trigger ... ok to process? */ if (skip_system) @@ -1341,7 +1382,7 @@ RelationBuildTriggers(Relation relation) build->tgfoid = pg_trigger->tgfoid; build->tgtype = pg_trigger->tgtype; build->tgenabled = pg_trigger->tgenabled; - build->tgisconstraint = pg_trigger->tgisconstraint; + build->tgisinternal = pg_trigger->tgisinternal; build->tgconstrrelid = pg_trigger->tgconstrrelid; build->tgconstrindid = pg_trigger->tgconstrindid; build->tgconstraint = pg_trigger->tgconstraint; @@ -1699,7 +1740,7 @@ equalTriggerDescs(TriggerDesc *trigdesc1, TriggerDesc *trigdesc2) return false; if (trig1->tgenabled != trig2->tgenabled) return false; - if (trig1->tgisconstraint != trig2->tgisconstraint) + if (trig1->tgisinternal != trig2->tgisinternal) return false; if (trig1->tgconstrrelid != trig2->tgconstrrelid) return false; @@ -3838,26 +3879,31 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt) } else { + Relation conrel; Relation tgrel; - ListCell *l; - List *oidlist = NIL; + List *conoidlist = NIL; + List *tgoidlist = NIL; + ListCell *lc; - /* ---------- + /* * Handle SET CONSTRAINTS constraint-name [, ...] - * First lookup all trigger Oid's for the constraint names. - * ---------- + * + * First, identify all the named constraints and make a list of their + * OIDs. Since, unlike the SQL spec, we allow multiple constraints + * of the same name within a schema, the specifications are not + * necessarily unique. Our strategy is to target all matching + * constraints within the first search-path schema that has any + * matches, but disregard matches in schemas beyond the first match. + * (This is a bit odd but it's the historical behavior.) */ - tgrel = heap_open(TriggerRelationId, AccessShareLock); + conrel = heap_open(ConstraintRelationId, AccessShareLock); - foreach(l, stmt->constraints) + foreach(lc, stmt->constraints) { - RangeVar *constraint = lfirst(l); - ScanKeyData skey; - SysScanDesc tgscan; - HeapTuple htup; + RangeVar *constraint = lfirst(lc); bool found; - List *namespaceSearchList; - ListCell *namespaceSearchCell; + List *namespacelist; + ListCell *nslc; if (constraint->catalogname) { @@ -3878,94 +3924,49 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt) { Oid namespaceId = LookupExplicitNamespace(constraint->schemaname); - namespaceSearchList = list_make1_oid(namespaceId); + namespacelist = list_make1_oid(namespaceId); } else { - namespaceSearchList = fetch_search_path(true); + namespacelist = fetch_search_path(true); } found = false; - foreach(namespaceSearchCell, namespaceSearchList) + foreach(nslc, namespacelist) { - Oid searchNamespaceId = lfirst_oid(namespaceSearchCell); + Oid namespaceId = lfirst_oid(nslc); + SysScanDesc conscan; + ScanKeyData skey[2]; + HeapTuple tup; - /* - * Setup to scan pg_trigger by tgconstrname ... - */ - ScanKeyInit(&skey, - Anum_pg_trigger_tgconstrname, + ScanKeyInit(&skey[0], + Anum_pg_constraint_conname, BTEqualStrategyNumber, F_NAMEEQ, - PointerGetDatum(constraint->relname)); + CStringGetDatum(constraint->relname)); + ScanKeyInit(&skey[1], + Anum_pg_constraint_connamespace, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(namespaceId)); - tgscan = systable_beginscan(tgrel, TriggerConstrNameIndexId, true, - SnapshotNow, 1, &skey); + conscan = systable_beginscan(conrel, ConstraintNameNspIndexId, + true, SnapshotNow, 2, skey); - /* - * ... and search for the constraint trigger row - */ - while (HeapTupleIsValid(htup = systable_getnext(tgscan))) + while (HeapTupleIsValid(tup = systable_getnext(conscan))) { - Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup); - Oid constraintNamespaceId; - - /* - * Foreign key constraints have triggers on both the - * parent and child tables. Since these tables may be in - * different schemas we must pick the child table because - * that table "owns" the constraint. - * - * Referential triggers on the parent table other than - * NOACTION_DEL and NOACTION_UPD are ignored below, so it - * is possible to not check them here, but it seems safer - * to always check. - */ - if (pg_trigger->tgfoid == F_RI_FKEY_NOACTION_DEL || - pg_trigger->tgfoid == F_RI_FKEY_NOACTION_UPD || - pg_trigger->tgfoid == F_RI_FKEY_RESTRICT_UPD || - pg_trigger->tgfoid == F_RI_FKEY_RESTRICT_DEL || - pg_trigger->tgfoid == F_RI_FKEY_CASCADE_UPD || - pg_trigger->tgfoid == F_RI_FKEY_CASCADE_DEL || - pg_trigger->tgfoid == F_RI_FKEY_SETNULL_UPD || - pg_trigger->tgfoid == F_RI_FKEY_SETNULL_DEL || - pg_trigger->tgfoid == F_RI_FKEY_SETDEFAULT_UPD || - pg_trigger->tgfoid == F_RI_FKEY_SETDEFAULT_DEL) - constraintNamespaceId = get_rel_namespace(pg_trigger->tgconstrrelid); - else - constraintNamespaceId = get_rel_namespace(pg_trigger->tgrelid); + Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup); - /* - * If this constraint is not in the schema we're currently - * searching for, keep looking. - */ - if (constraintNamespaceId != searchNamespaceId) - continue; - - /* - * If we found some, check that they fit the deferrability - * but skip referential action ones, since they are - * silently never deferrable. - */ - if (pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD && - pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL && - pg_trigger->tgfoid != F_RI_FKEY_CASCADE_UPD && - pg_trigger->tgfoid != F_RI_FKEY_CASCADE_DEL && - pg_trigger->tgfoid != F_RI_FKEY_SETNULL_UPD && - pg_trigger->tgfoid != F_RI_FKEY_SETNULL_DEL && - pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_UPD && - pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_DEL) - { - if (stmt->deferred && !pg_trigger->tgdeferrable) - ereport(ERROR, - (errcode(ERRCODE_WRONG_OBJECT_TYPE), - errmsg("constraint \"%s\" is not deferrable", - constraint->relname))); - oidlist = lappend_oid(oidlist, HeapTupleGetOid(htup)); - } + if (con->condeferrable) + conoidlist = lappend_oid(conoidlist, + HeapTupleGetOid(tup)); + else if (stmt->deferred) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("constraint \"%s\" is not deferrable", + constraint->relname))); found = true; } - systable_endscan(tgscan); + systable_endscan(conscan); /* * Once we've found a matching constraint we do not search @@ -3973,10 +3974,9 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt) */ if (found) break; - } - list_free(namespaceSearchList); + list_free(namespacelist); /* * Not found ? @@ -3987,14 +3987,67 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt) errmsg("constraint \"%s\" does not exist", constraint->relname))); } + + heap_close(conrel, AccessShareLock); + + /* + * Now, locate the trigger(s) implementing each of these constraints, + * and make a list of their OIDs. + */ + tgrel = heap_open(TriggerRelationId, AccessShareLock); + + foreach(lc, conoidlist) + { + Oid conoid = lfirst_oid(lc); + bool found; + ScanKeyData skey; + SysScanDesc tgscan; + HeapTuple htup; + + found = false; + + ScanKeyInit(&skey, + Anum_pg_trigger_tgconstraint, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(conoid)); + + tgscan = systable_beginscan(tgrel, TriggerConstraintIndexId, true, + SnapshotNow, 1, &skey); + + while (HeapTupleIsValid(htup = systable_getnext(tgscan))) + { + Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup); + + /* + * Silently skip triggers that are marked as non-deferrable + * in pg_trigger. This is not an error condition, since + * a deferrable RI constraint may have some non-deferrable + * actions. + */ + if (pg_trigger->tgdeferrable) + tgoidlist = lappend_oid(tgoidlist, + HeapTupleGetOid(htup)); + + found = true; + } + + systable_endscan(tgscan); + + /* Safety check: a deferrable constraint should have triggers */ + if (!found) + elog(ERROR, "no triggers found for constraint with OID %u", + conoid); + } + heap_close(tgrel, AccessShareLock); /* - * Set the trigger states of individual triggers for this xact. + * Now we can set the trigger states of individual triggers for this + * xact. */ - foreach(l, oidlist) + foreach(lc, tgoidlist) { - Oid tgoid = lfirst_oid(l); + Oid tgoid = lfirst_oid(lc); SetConstraintState state = afterTriggers->state; bool found = false; int i; |