Change StoreCatalogInheritance() to work from a list of parent relation

OIDs rather than names.  Aside from being simpler and faster, this way
doesn't blow up in the face of 'create temp table foo () inherits (foo)'.
Which is a rather odd thing to do, but it seems some people want to.

Author: tglsfdc

src/backend/commands/creatinh.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/creatinh.c,v 1.67 2000/11/16 22:30:18 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/Attic/creatinh.c,v 1.68 2000/12/14 00:41:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -34,10 +34,10 @@
 
 static int checkAttrExists(const char *attributeName,
 				const char *attributeType, List *schema);
-static List *MergeAttributes(List *schema, List *supers, List **supconstr);
+static List *MergeAttributes(List *schema, List *supers,
+							 List **supOids, List **supconstr);
 static void StoreCatalogInheritance(Oid relationId, List *supers);
-static void
-setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
+static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
 
 
 /* ----------------------------------------------------------------
@@ -53,8 +53,8 @@ DefineRelation(CreateStmt *stmt, char relkind)
 	int			numberOfAttributes;
 	Oid			relationId;
 	Relation	rel;
-	List	   *inheritList;
 	TupleDesc	descriptor;
+	List	   *inheritOids;
 	List	   *old_constraints;
 	List	   *rawDefaults;
 	List	   *listptr;
@@ -67,24 +67,16 @@ DefineRelation(CreateStmt *stmt, char relkind)
 	StrNCpy(relname, stmt->relname, NAMEDATALEN);
 
 	/* ----------------
-	 *	Handle parameters
-	 *	XXX parameter handling missing below.
+	 *	Look up inheritance ancestors and generate relation schema,
+	 *	including inherited attributes.
 	 * ----------------
 	 */
-	inheritList = stmt->inhRelnames;
-
-	/* ----------------
-	 *	generate relation schema, including inherited attributes.
-	 * ----------------
-	 */
-	schema = MergeAttributes(schema, inheritList, &old_constraints);
+	schema = MergeAttributes(schema, stmt->inhRelnames,
+							 &inheritOids, &old_constraints);
 
 	numberOfAttributes = length(schema);
 	if (numberOfAttributes <= 0)
-	{
-		elog(ERROR, "DefineRelation: %s",
-			 "please inherit from a relation or define an attribute");
-	}
+		elog(ERROR, "DefineRelation: please inherit from a relation or define an attribute");
 
 	/* ----------------
 	 *	create a relation descriptor from the relation schema
@@ -147,7 +139,7 @@ DefineRelation(CreateStmt *stmt, char relkind)
 										  relkind, stmt->istemp,
 										  allowSystemTableMods);
 
-	StoreCatalogInheritance(relationId, inheritList);
+	StoreCatalogInheritance(relationId, inheritOids);
 
 	/*
 	 * We must bump the command counter to make the newly-created relation
@@ -286,10 +278,15 @@ change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
  * MergeAttributes
  *		Returns new schema given initial schema and supers.
  *
+ * Input arguments:
  *
  * 'schema' is the column/attribute definition for the table. (It's a list
  *		of ColumnDef's.) It is destructively changed.
- * 'inheritList' is the list of inherited relations (a list of Value(str)'s).
+ * 'supers' is a list of names (as Value objects) of parent relations.
+ *
+ * Output arguments:
+ * 'supOids' receives an integer list of the OIDs of the parent relations.
+ * 'supconstr' receives a list of constraints belonging to the parents.
  *
  * Notes:
  *	  The order in which the attributes are inherited is very important.
@@ -314,12 +311,14 @@ change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
  *						   stud_emp {7:percent}
  */
 static List *
-MergeAttributes(List *schema, List *supers, List **supconstr)
+MergeAttributes(List *schema, List *supers,
+				List **supOids, List **supconstr)
 {
 	List	   *entry;
 	List	   *inhSchema = NIL;
+	List	   *parentOids = NIL;
 	List	   *constraints = NIL;
-	int		attnums;
+	int			attnums;
 
 	/*
 	 * Validates that there are no duplications. Validity checking of
@@ -338,7 +337,7 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 			 */
 			ColumnDef  *restdef = lfirst(rest);
 
-			if (!strcmp(coldef->colname, restdef->colname))
+			if (strcmp(coldef->colname, restdef->colname) == 0)
 			{
 				elog(ERROR, "CREATE TABLE: attribute \"%s\" duplicated",
 					 coldef->colname);
@@ -351,7 +350,7 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 
 		foreach(rest, lnext(entry))
 		{
-			if (!strcmp(strVal(lfirst(entry)), strVal(lfirst(rest))))
+			if (strcmp(strVal(lfirst(entry)), strVal(lfirst(rest))) == 0)
 			{
 				elog(ERROR, "CREATE TABLE: inherited relation \"%s\" duplicated",
 					 strVal(lfirst(entry)));
@@ -376,6 +375,11 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 		int		i, attidx, attno_exist;
 
 		relation = heap_openr(name, AccessShareLock);
+
+		if (relation->rd_rel->relkind != RELKIND_RELATION)
+			elog(ERROR, "CREATE TABLE: inherited relation \"%s\" is not a table", name);
+
+		parentOids = lappendi(parentOids, relation->rd_id);
 		setRelhassubclassInRelation(relation->rd_id, true);
 		tupleDesc = RelationGetDescr(relation);
 		/* allocate a new attribute number table and initialize */
@@ -391,9 +395,6 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 			partialAttidx [i] = 0;
 		constr = tupleDesc->constr;
 
-		if (relation->rd_rel->relkind != RELKIND_RELATION)
-			elog(ERROR, "CREATE TABLE: inherited relation \"%s\" is not a table", name);
-
 		attidx = 0;
 		for (attrno = relation->rd_rel->relnatts - 1; attrno >= 0; attrno--)
 		{
@@ -519,13 +520,18 @@ MergeAttributes(List *schema, List *supers, List **supconstr)
 	 * put the inherited schema before our the schema for this table
 	 */
 	schema = nconc(inhSchema, schema);
+
+	*supOids = parentOids;
 	*supconstr = constraints;
 	return schema;
 }
 
 /*
  * StoreCatalogInheritance
  *		Updates the system catalogs with proper inheritance information.
+ *
+ * supers is an integer list of the OIDs of the new relation's direct
+ * ancestors.  NB: it is destructively changed to include indirect ancestors.
  */
 static void
 StoreCatalogInheritance(Oid relationId, List *supers)
@@ -534,7 +540,6 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 	TupleDesc	desc;
 	int16		seqNumber;
 	List	   *entry;
-	List	   *idList;
 	HeapTuple	tuple;
 
 	/* ----------------
@@ -547,32 +552,19 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 		return;
 
 	/* ----------------
-	 * Catalog INHERITS information.
+	 * Catalog INHERITS information using direct ancestors only.
 	 * ----------------
 	 */
 	relation = heap_openr(InheritsRelationName, RowExclusiveLock);
 	desc = RelationGetDescr(relation);
 
 	seqNumber = 1;
-	idList = NIL;
 	foreach(entry, supers)
 	{
-		Oid			entryOid;
+		Oid			entryOid = lfirsti(entry);
 		Datum		datum[Natts_pg_inherits];
 		char		nullarr[Natts_pg_inherits];
 
-		entryOid = GetSysCacheOid(RELNAME,
-								  PointerGetDatum(strVal(lfirst(entry))),
-								  0, 0, 0);
-		if (!OidIsValid(entryOid))
-			elog(ERROR, "StoreCatalogInheritance: cache lookup failed for relation \"%s\"",
-				 strVal(lfirst(entry)));
-
-		/*
-		 * build idList for use below
-		 */
-		idList = lappendi(idList, entryOid);
-
 		datum[0] = ObjectIdGetDatum(relationId);	/* inhrel */
 		datum[1] = ObjectIdGetDatum(entryOid);		/* inhparent */
 		datum[2] = Int16GetDatum(seqNumber);		/* inhseqno */
@@ -602,21 +594,20 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 	heap_close(relation, RowExclusiveLock);
 
 	/* ----------------
-	 * Catalog IPL information.
+	 * Expand supers list to include indirect ancestors as well.
 	 *
 	 * Algorithm:
-	 *	0. list superclasses (by Oid) in order given (see idList).
+	 *	0. begin with list of direct superclasses.
 	 *	1. append after each relationId, its superclasses, recursively.
-	 *	3. remove all but last of duplicates.
-	 *	4. store result.
+	 *	2. remove all but last of duplicates.
 	 * ----------------
 	 */
 
 	/* ----------------
-	 *	1.
+	 *	1. append after each relationId, its superclasses, recursively.
 	 * ----------------
 	 */
-	foreach(entry, idList)
+	foreach(entry, supers)
 	{
 		HeapTuple	tuple;
 		Oid			id;
@@ -649,20 +640,21 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 	}
 
 	/* ----------------
-	 *	2.
+	 *	2. remove all but last of duplicates.
 	 * ----------------
 	 */
-	foreach(entry, idList)
+	foreach(entry, supers)
 	{
-		Oid			name;
+		Oid			thisone;
+		bool		found;
 		List	   *rest;
-		bool		found = false;
 
 again:
-		name = lfirsti(entry);
+		thisone = lfirsti(entry);
+		found = false;
 		foreach(rest, lnext(entry))
 		{
-			if (name == lfirsti(rest))
+			if (thisone == lfirsti(rest))
 			{
 				found = true;
 				break;
@@ -672,28 +664,25 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 		{
 
 			/*
-			 * entry list must be of length >= 2 or else no match
-			 *
-			 * so, remove this entry.
+			 * found a later duplicate, so remove this entry.
 			 */
-			lfirst(entry) = lfirst(lnext(entry));
+			lfirsti(entry) = lfirsti(lnext(entry));
 			lnext(entry) = lnext(lnext(entry));
 
-			found = false;
 			goto again;
 		}
 	}
 
 	/* ----------------
-	 *	3.
+	 * Catalog IPL information using expanded list.
 	 * ----------------
 	 */
 	relation = heap_openr(InheritancePrecidenceListRelationName, RowExclusiveLock);
 	desc = RelationGetDescr(relation);
 
 	seqNumber = 1;
 
-	foreach(entry, idList)
+	foreach(entry, supers)
 	{
 		Datum		datum[Natts_pg_ipl];
 		char		nullarr[Natts_pg_ipl];
@@ -721,10 +710,12 @@ StoreCatalogInheritance(Oid relationId, List *supers)
 
 
 /*
- * returns the index(star with 1) if attribute already exists in schema, 0 otherwise.
+ * returns the index (starting with 1) if attribute already exists in schema,
+ * 0 if it doesn't.
  */
 static int
-checkAttrExists(const char *attributeName, const char *attributeType, List *schema)
+checkAttrExists(const char *attributeName, const char *attributeType,
+				List *schema)
 {
 	List	   *s;
 	int	i = 0;