Make OIDs optional, per discussions in pghackers. WITH OIDS is still the

default, but OIDS are removed from many system catalogs that don't need them.
Some interesting side effects: TOAST pointers are 20 bytes not 32 now;
pg_description has a three-column key instead of one.

Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey
has some usefulness; pg_dump dumps comments on indexes, rules, and
triggers in a valid order.

initdb forced.

1 files changed, 27 insertions, 8 deletions

diff --git a/src/include/catalog/pg_description.h b/src/include/catalog/pg_description.h
index 0b5d342c0d..e3f21a49b6 100644
--- a/src/include/catalog/pg_description.h
+++ b/src/include/catalog/pg_description.h
@@ -3,11 +3,26 @@
  * pg_description.h
  *	  definition of the system "description" relation (pg_description)
  *
+ * NOTE: an object is identified by the OID of the row that primarily
+ * defines the object, plus the OID of the table that that row appears in.
+ * For example, a function is identified by the OID of its pg_proc row
+ * plus the pg_class OID of table pg_proc.  This allows unique identification
+ * of objects without assuming that OIDs are unique across tables.
+ *
+ * Since attributes don't have OIDs of their own, we identify an attribute
+ * comment by the objoid+classoid of its parent table, plus an "objsubid"
+ * giving the attribute column number.  "objsubid" must be zero in a comment
+ * for a table itself, so that it is distinct from any column comment.
+ * Currently, objsubid is unused and zero for all other kinds of objects,
+ * but perhaps it might be useful someday to associate comments with
+ * constituent elements of other kinds of objects (arguments of a function,
+ * for example).
+ *
  *
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: pg_description.h,v 1.12 2001/01/24 19:43:21 momjian Exp $
+ * $Id: pg_description.h,v 1.13 2001/08/10 18:57:40 tgl Exp $
  *
  * NOTES
  *		the genbki.sh script reads this file and generates .bki
@@ -33,10 +48,12 @@
  *		typedef struct FormData_pg_description
  * ----------------
  */
-CATALOG(pg_description)
+CATALOG(pg_description) BKI_WITHOUT_OIDS
 {
-	Oid			objoid;
-	text		description;
+	Oid			objoid;			/* OID of object itself */
+	Oid			classoid;		/* OID of table containing object */
+	int4		objsubid;		/* column number, or 0 if not used */
+	text		description;	/* description of object */
 } FormData_pg_description;
 
 /* ----------------
@@ -50,9 +67,11 @@ typedef FormData_pg_description *Form_pg_description;
  *		compiler constants for pg_descrpition
  * ----------------
  */
-#define Natts_pg_description			2
+#define Natts_pg_description			4
 #define Anum_pg_description_objoid		1
-#define Anum_pg_description_description 2
+#define Anum_pg_description_classoid	2
+#define Anum_pg_description_objsubid	3
+#define Anum_pg_description_description 4
 
 /* ----------------
  *		initial contents of pg_description
@@ -61,8 +80,8 @@ typedef FormData_pg_description *Form_pg_description;
 
 /*
  *	Because the contents of this table are taken from the other *.h files,
- *	there is no initialization. It is loaded from initdb using a COPY
- *	statement.
+ *	there is no initialization here.  The initial contents are extracted
+ *	by genbki.sh and loaded during initdb.
  */
 
 #endif	 /* PG_DESCRIPTION_H */