Code review for ON COMMIT patch. Make the actual on-commit action happen

before commit, not after :-( --- the original coding is not only unsafe
if an error occurs while it's processing, but it generates an invalid
sequence of WAL entries.  Resurrect 7.2 logic for deleting items when
no longer needed.  Use an enum instead of random macros.  Editorialize
on names used for routines and constants.  Teach backend/nodes routines
about new field in CreateTable struct.  Add a regression test.

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.211 2002/11/09 23:56:39 momjian Exp $
+ * $Id: parsenodes.h,v 1.212 2002/11/11 22:19:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -911,6 +911,16 @@ typedef struct CopyStmt
  * implementation).
  * ----------------------
  */
+
+/* What to do at commit time for temporary relations */
+typedef enum OnCommitAction
+{
+	ONCOMMIT_NOOP,				/* No ON COMMIT clause (do nothing) */
+	ONCOMMIT_PRESERVE_ROWS,		/* ON COMMIT PRESERVE ROWS (do nothing) */
+	ONCOMMIT_DELETE_ROWS,		/* ON COMMIT DELETE ROWS */
+	ONCOMMIT_DROP				/* ON COMMIT DROP */
+} OnCommitAction;
+
 typedef struct CreateStmt
 {
 	NodeTag		type;
@@ -919,7 +929,7 @@ typedef struct CreateStmt
 	List	   *inhRelations;	/* relations to inherit from */
 	List	   *constraints;	/* constraints (list of Constraint nodes) */
 	bool		hasoids;		/* should it have OIDs? */
-	char		ateoxact;		/* what do we do at COMMIT for TEMP ? */
+	OnCommitAction oncommit;	/* what do we do at COMMIT? */
 } CreateStmt;
 
 /* ----------