Add system catalog columns pg_constraint.conindid and pg_trigger.tgconstrindid.

conindid is the index supporting a constraint.  We can use this not only for
unique/primary-key constraints, but also foreign-key constraints, which
depend on the unique index that constrains the referenced columns.
tgconstrindid is just copied from the constraint's conindid field, or is
zero for triggers not associated with constraints.

This is mainly intended as infrastructure for upcoming patches, but it has
some virtue in itself, since it exposes a relationship that you formerly
had to grovel in pg_depend to determine.  I simplified one information_schema
view accordingly.  (There is a pg_dump query that could also use conindid,
but I left it alone because it wasn't clear it'd get any faster.)

1 files changed, 18 insertions, 12 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 20253e1523..e883e8ed91 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.291 2009/07/20 02:42:27 adunstan Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.292 2009/07/28 02:56:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -152,6 +152,7 @@ typedef struct NewConstraint
 	char	   *name;			/* Constraint name, or NULL if none */
 	ConstrType	contype;		/* CHECK or FOREIGN */
 	Oid			refrelid;		/* PK rel, if FOREIGN */
+	Oid			refindid;		/* OID of PK's index, if FOREIGN */
 	Oid			conid;			/* OID of pg_constraint entry, if FOREIGN */
 	Node	   *qual;			/* Check expr or FkConstraint struct */
 	List	   *qualstate;		/* Execution state for CHECK */
@@ -247,9 +248,10 @@ static Oid transformFkeyCheckAttrs(Relation pkrel,
 						Oid *opclasses);
 static void checkFkeyPermissions(Relation rel, int16 *attnums, int natts);
 static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
-							 Relation rel, Relation pkrel, Oid constraintOid);
+							 Relation rel, Relation pkrel,
+							 Oid pkindOid, Oid constraintOid);
 static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
-						 Oid constraintOid);
+						 Oid constraintOid, Oid indexOid);
 static void ATController(Relation rel, List *cmds, bool recurse);
 static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		  bool recurse, bool recursing);
@@ -2915,6 +2917,7 @@ ATRewriteTables(List **wqueue)
 				refrel = heap_open(con->refrelid, RowShareLock);
 
 				validateForeignKeyConstraint(fkconstraint, rel, refrel,
+											 con->refindid,
 											 con->conid);
 
 				heap_close(refrel, NoLock);
@@ -4819,6 +4822,7 @@ ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 									  numfks,
 									  InvalidOid,		/* not a domain
 														 * constraint */
+									  indexOid,
 									  RelationGetRelid(pkrel),
 									  pkattnum,
 									  pfeqoperators,
@@ -4828,7 +4832,6 @@ ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 									  fkconstraint->fk_upd_action,
 									  fkconstraint->fk_del_action,
 									  fkconstraint->fk_matchtype,
-									  indexOid,
 									  NULL,		/* no check constraint */
 									  NULL,
 									  NULL,
@@ -4838,7 +4841,7 @@ ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 	/*
 	 * Create the triggers that will enforce the constraint.
 	 */
-	createForeignKeyTriggers(rel, fkconstraint, constrOid);
+	createForeignKeyTriggers(rel, fkconstraint, constrOid, indexOid);
 
 	/*
 	 * Tell Phase 3 to check that the constraint is satisfied by existing rows
@@ -4852,6 +4855,7 @@ ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 		newcon->name = fkconstraint->constr_name;
 		newcon->contype = CONSTR_FOREIGN;
 		newcon->refrelid = RelationGetRelid(pkrel);
+		newcon->refindid = indexOid;
 		newcon->conid = constrOid;
 		newcon->qual = (Node *) fkconstraint;
 
@@ -5141,6 +5145,7 @@ static void
 validateForeignKeyConstraint(FkConstraint *fkconstraint,
 							 Relation rel,
 							 Relation pkrel,
+							 Oid pkindOid,
 							 Oid constraintOid)
 {
 	HeapScanDesc scan;
@@ -5156,6 +5161,7 @@ validateForeignKeyConstraint(FkConstraint *fkconstraint,
 	trig.tgenabled = TRIGGER_FIRES_ON_ORIGIN;
 	trig.tgisconstraint = TRUE;
 	trig.tgconstrrelid = RelationGetRelid(pkrel);
+	trig.tgconstrindid = pkindOid;
 	trig.tgconstraint = constraintOid;
 	trig.tgdeferrable = FALSE;
 	trig.tginitdeferred = FALSE;
@@ -5209,7 +5215,7 @@ validateForeignKeyConstraint(FkConstraint *fkconstraint,
 
 static void
 CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
-					 Oid constraintOid, bool on_insert)
+					 Oid constraintOid, Oid indexOid, bool on_insert)
 {
 	CreateTrigStmt *fk_trigger;
 
@@ -5237,7 +5243,7 @@ CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
 	fk_trigger->constrrel = fkconstraint->pktable;
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
 
 	/* Make changes-so-far visible */
 	CommandCounterIncrement();
@@ -5248,7 +5254,7 @@ CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
  */
 static void
 createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
-						 Oid constraintOid)
+						 Oid constraintOid, Oid indexOid)
 {
 	RangeVar   *myRel;
 	CreateTrigStmt *fk_trigger;
@@ -5267,8 +5273,8 @@ createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 	 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
 	 * action for both INSERTs and UPDATEs on the referencing table.
 	 */
-	CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, true);
-	CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, false);
+	CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, indexOid, true);
+	CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, indexOid, false);
 
 	/*
 	 * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
@@ -5316,7 +5322,7 @@ createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 	}
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
 
 	/* Make changes-so-far visible */
 	CommandCounterIncrement();
@@ -5367,7 +5373,7 @@ createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 	}
 	fk_trigger->args = NIL;
 
-	(void) CreateTrigger(fk_trigger, constraintOid, false);
+	(void) CreateTrigger(fk_trigger, constraintOid, indexOid, false);
 }
 
 /*