Second phase of committing Rod Taylor's pg_depend/pg_constraint patch.

pg_relcheck is gone; CHECK, UNIQUE, PRIMARY KEY, and FOREIGN KEY
constraints all have real live entries in pg_constraint.  pg_depend
exists, and RESTRICT/CASCADE options work on most kinds of DROP;
however, pg_depend is not yet very well populated with dependencies.
(Most of the ones that are present at this point just replace formerly
hardwired associations, such as the implicit drop of a relation's pg_type
entry when the relation is dropped.)  Need to add more logic to create
dependency entries, improve pg_dump to dump constraints in place of
indexes and triggers, and add some regression tests.

3 files changed, 109 insertions, 98 deletions

diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index 43f8ffd6f1f..5922cb4ab5b 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.73 2002/06/20 20:29:33 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.74 2002/07/12 18:43:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,6 +16,7 @@
 
 #include "access/heapam.h"
 #include "catalog/catname.h"
+#include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/pg_rewrite.h"
 #include "commands/view.h"
@@ -57,6 +58,8 @@ InsertRule(char *rulname,
 	TupleDesc	tupDesc;
 	HeapTuple	tup;
 	Oid			rewriteObjectId;
+	ObjectAddress	myself,
+					referenced;
 
 	if (IsDefinedRewriteRule(eventrel_oid, rulname))
 		elog(ERROR, "Attempt to insert rule \"%s\" failed: already exists",
@@ -103,6 +106,23 @@ InsertRule(char *rulname,
 
 	heap_freetuple(tup);
 
+	/*
+	 * Install dependency on rule's relation to ensure it will go away
+	 * on relation deletion.  If the rule is ON SELECT, make the dependency
+	 * implicit --- this prevents deleting a view's SELECT rule.  Other
+	 * kinds of rules can be AUTO.
+	 */
+	myself.classId = RelationGetRelid(pg_rewrite_desc);
+	myself.objectId = rewriteObjectId;
+	myself.objectSubId = 0;
+
+	referenced.classId = RelOid_pg_class;
+	referenced.objectId = eventrel_oid;
+	referenced.objectSubId = 0;
+
+	recordDependencyOn(&myself, &referenced,
+		(evtype == CMD_SELECT) ? DEPENDENCY_INTERNAL : DEPENDENCY_AUTO);
+
 	heap_close(pg_rewrite_desc, RowExclusiveLock);
 
 	return rewriteObjectId;
diff --git a/src/backend/rewrite/rewriteRemove.c b/src/backend/rewrite/rewriteRemove.c
index 71fd4d5ac40..4ce9f3f2b90 100644
--- a/src/backend/rewrite/rewriteRemove.c
+++ b/src/backend/rewrite/rewriteRemove.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.50 2002/06/20 20:29:34 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteRemove.c,v 1.51 2002/07/12 18:43:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -17,14 +17,15 @@
 #include "access/genam.h"
 #include "access/heapam.h"
 #include "catalog/catname.h"
+#include "catalog/dependency.h"
 #include "catalog/indexing.h"
 #include "catalog/pg_rewrite.h"
-#include "commands/comment.h"
 #include "miscadmin.h"
 #include "rewrite/rewriteRemove.h"
 #include "rewrite/rewriteSupport.h"
 #include "utils/acl.h"
 #include "utils/fmgroids.h"
+#include "utils/lsyscache.h"
 #include "utils/syscache.h"
 
 
@@ -34,77 +35,102 @@
  * Delete a rule given its name.
  */
 void
-RemoveRewriteRule(Oid owningRel, const char *ruleName)
+RemoveRewriteRule(Oid owningRel, const char *ruleName, DropBehavior behavior)
 {
-	Relation	RewriteRelation;
-	Relation	event_relation;
 	HeapTuple	tuple;
-	Oid			ruleId;
 	Oid			eventRelationOid;
-	bool		hasMoreRules;
 	AclResult	aclresult;
-
-	/*
-	 * Open the pg_rewrite relation.
-	 */
-	RewriteRelation = heap_openr(RewriteRelationName, RowExclusiveLock);
+	ObjectAddress object;
 
 	/*
 	 * Find the tuple for the target rule.
 	 */
-	tuple = SearchSysCacheCopy(RULERELNAME,
-							   ObjectIdGetDatum(owningRel),
-							   PointerGetDatum(ruleName),
-							   0, 0);
+	tuple = SearchSysCache(RULERELNAME,
+						   ObjectIdGetDatum(owningRel),
+						   PointerGetDatum(ruleName),
+						   0, 0);
 
 	/*
-	 * complain if no rule with such name existed
+	 * complain if no rule with such name exists
 	 */
 	if (!HeapTupleIsValid(tuple))
 		elog(ERROR, "Rule \"%s\" not found", ruleName);
 
 	/*
-	 * Save the OID of the rule (i.e. the tuple's OID) and the event
-	 * relation's OID
+	 * Verify user has appropriate permissions.
 	 */
-	ruleId = tuple->t_data->t_oid;
 	eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
 	Assert(eventRelationOid == owningRel);
+	aclresult = pg_class_aclcheck(eventRelationOid, GetUserId(), ACL_RULE);
+	if (aclresult != ACLCHECK_OK)
+		aclcheck_error(aclresult, get_rel_name(eventRelationOid));
 
 	/*
-	 * We had better grab AccessExclusiveLock so that we know no other
-	 * rule additions/deletions are going on for this relation.  Else we
-	 * cannot set relhasrules correctly.  Besides, we don't want to be
-	 * changing the ruleset while queries are executing on the rel.
+	 * Do the deletion
 	 */
-	event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
+	object.classId = get_system_catalog_relid(RewriteRelationName);
+	object.objectId = tuple->t_data->t_oid;
+	object.objectSubId = 0;
+
+	ReleaseSysCache(tuple);
+
+	performDeletion(&object, behavior);
+}
+
+
+/*
+ * Guts of rule deletion.
+ */
+void
+RemoveRewriteRuleById(Oid ruleOid)
+{
+	Relation	RewriteRelation;
+	ScanKeyData		skey[1];
+	SysScanDesc		rcscan;
+	Relation	event_relation;
+	HeapTuple	tuple;
+	Oid			eventRelationOid;
+	bool		hasMoreRules;
 
 	/*
-	 * Verify user has appropriate permissions.
+	 * Open the pg_rewrite relation.
 	 */
-	aclresult = pg_class_aclcheck(eventRelationOid, GetUserId(), ACL_RULE);
-	if (aclresult != ACLCHECK_OK)
-		aclcheck_error(aclresult, RelationGetRelationName(event_relation));
+	RewriteRelation = heap_openr(RewriteRelationName, RowExclusiveLock);
+
+	/*
+	 * Find the tuple for the target rule.
+	 */
+	ScanKeyEntryInitialize(&skey[0], 0x0,
+						   ObjectIdAttributeNumber, F_OIDEQ,
+						   ObjectIdGetDatum(ruleOid));
 
-	/* do not allow the removal of a view's SELECT rule */
-	if (event_relation->rd_rel->relkind == RELKIND_VIEW &&
-		((Form_pg_rewrite) GETSTRUCT(tuple))->ev_type == '1')
-		elog(ERROR, "Cannot remove a view's SELECT rule");
+	rcscan = systable_beginscan(RewriteRelation, RewriteOidIndex, true,
+								SnapshotNow, 1, skey);
 
-	hasMoreRules = event_relation->rd_rules != NULL &&
-		event_relation->rd_rules->numLocks > 1;
+	tuple = systable_getnext(rcscan);
+
+	if (!HeapTupleIsValid(tuple))
+		elog(ERROR, "RemoveRewriteRuleById: Rule %u does not exist",
+			 ruleOid);
 
 	/*
-	 * Delete any comments associated with this rule
+	 * We had better grab AccessExclusiveLock so that we know no other
+	 * rule additions/deletions are going on for this relation.  Else we
+	 * cannot set relhasrules correctly.  Besides, we don't want to be
+	 * changing the ruleset while queries are executing on the rel.
 	 */
-	DeleteComments(ruleId, RelationGetRelid(RewriteRelation));
+	eventRelationOid = ((Form_pg_rewrite) GETSTRUCT(tuple))->ev_class;
+	event_relation = heap_open(eventRelationOid, AccessExclusiveLock);
+
+	hasMoreRules = event_relation->rd_rules != NULL &&
+		event_relation->rd_rules->numLocks > 1;
 
 	/*
 	 * Now delete the pg_rewrite tuple for the rule
 	 */
 	simple_heap_delete(RewriteRelation, &tuple->t_self);
 
-	heap_freetuple(tuple);
+	systable_endscan(rcscan);
 
 	heap_close(RewriteRelation, RowExclusiveLock);
 
@@ -120,49 +146,3 @@ RemoveRewriteRule(Oid owningRel, const char *ruleName)
 	/* Close rel, but keep lock till commit... */
 	heap_close(event_relation, NoLock);
 }
-
-/*
- * RelationRemoveRules -
- *	  removes all rules associated with the relation when the relation is
- *	  being removed.
- */
-void
-RelationRemoveRules(Oid relid)
-{
-	Relation	RewriteRelation;
-	SysScanDesc scanDesc;
-	ScanKeyData scanKeyData;
-	HeapTuple	tuple;
-
-	/*
-	 * Open the pg_rewrite relation.
-	 */
-	RewriteRelation = heap_openr(RewriteRelationName, RowExclusiveLock);
-
-	/*
-	 * Scan pg_rewrite for all the tuples that have the same ev_class
-	 * as relid (the relation to be removed).
-	 */
-	ScanKeyEntryInitialize(&scanKeyData,
-						   0,
-						   Anum_pg_rewrite_ev_class,
-						   F_OIDEQ,
-						   ObjectIdGetDatum(relid));
-
-	scanDesc = systable_beginscan(RewriteRelation,
-								  RewriteRelRulenameIndex,
-								  true, SnapshotNow,
-								  1, &scanKeyData);
-
-	while (HeapTupleIsValid(tuple = systable_getnext(scanDesc)))
-	{
-		/* Delete any comments associated with this rule */
-		DeleteComments(tuple->t_data->t_oid, RelationGetRelid(RewriteRelation));
-
-		simple_heap_delete(RewriteRelation, &tuple->t_self);
-	}
-
-	systable_endscan(scanDesc);
-
-	heap_close(RewriteRelation, RowExclusiveLock);
-}
diff --git a/src/backend/rewrite/rewriteSupport.c b/src/backend/rewrite/rewriteSupport.c
index ba590b8cc66..3f4c7f23871 100644
--- a/src/backend/rewrite/rewriteSupport.c
+++ b/src/backend/rewrite/rewriteSupport.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteSupport.c,v 1.52 2002/06/20 20:29:34 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteSupport.c,v 1.53 2002/07/12 18:43:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,6 +18,7 @@
 #include "catalog/catname.h"
 #include "catalog/indexing.h"
 #include "rewrite/rewriteSupport.h"
+#include "utils/inval.h"
 #include "utils/syscache.h"
 
 
@@ -44,9 +45,8 @@ IsDefinedRewriteRule(Oid owningRel, const char *ruleName)
  * NOTE: an important side-effect of this operation is that an SI invalidation
  * message is sent out to all backends --- including me --- causing relcache
  * entries to be flushed or updated with the new set of rules for the table.
- * Therefore, we execute the update even if relhasrules has the right value
- * already.  Possible future improvement: skip the disk update and just send
- * an SI message in that case.
+ * This must happen even if we find that no change is needed in the pg_class
+ * row.
  */
 void
 SetRelationRuleStatus(Oid relationId, bool relHasRules,
@@ -54,6 +54,7 @@ SetRelationRuleStatus(Oid relationId, bool relHasRules,
 {
 	Relation	relationRelation;
 	HeapTuple	tuple;
+	Form_pg_class classForm;
 	Relation	idescs[Num_pg_class_indices];
 
 	/*
@@ -66,18 +67,28 @@ SetRelationRuleStatus(Oid relationId, bool relHasRules,
 							   0, 0, 0);
 	if (!HeapTupleIsValid(tuple))
 		elog(ERROR, "SetRelationRuleStatus: cache lookup failed for relation %u", relationId);
+	classForm = (Form_pg_class) GETSTRUCT(tuple);
 
-	/* Do the update */
-	((Form_pg_class) GETSTRUCT(tuple))->relhasrules = relHasRules;
-	if (relIsBecomingView)
-		((Form_pg_class) GETSTRUCT(tuple))->relkind = RELKIND_VIEW;
+	if (classForm->relhasrules != relHasRules ||
+		(relIsBecomingView && classForm->relkind != RELKIND_VIEW))
+	{
+		/* Do the update */
+		classForm->relhasrules = relHasRules;
+		if (relIsBecomingView)
+			classForm->relkind = RELKIND_VIEW;
 
-	simple_heap_update(relationRelation, &tuple->t_self, tuple);
+		simple_heap_update(relationRelation, &tuple->t_self, tuple);
 
-	/* Keep the catalog indices up to date */
-	CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
-	CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
-	CatalogCloseIndices(Num_pg_class_indices, idescs);
+		/* Keep the catalog indices up to date */
+		CatalogOpenIndices(Num_pg_class_indices, Name_pg_class_indices, idescs);
+		CatalogIndexInsert(idescs, Num_pg_class_indices, relationRelation, tuple);
+		CatalogCloseIndices(Num_pg_class_indices, idescs);
+	}
+	else
+	{
+		/* no need to change tuple, but force relcache rebuild anyway */
+		CacheInvalidateRelcache(relationId);
+	}
 
 	heap_freetuple(tuple);
 	heap_close(relationRelation, RowExclusiveLock);