Make CREATE/ALTER/DROP USER/GROUP transaction-safe, or at least pretty

nearly so, by postponing write of flat password file until transaction
commit.

src/backend/access/transam/xact.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.132 2002/09/04 20:31:13 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.133 2002/10/21 19:46:45 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -167,6 +167,7 @@
 #include "catalog/namespace.h"
 #include "commands/async.h"
 #include "commands/trigger.h"
+#include "commands/user.h"
 #include "executor/spi.h"
 #include "libpq/be-fsstubs.h"
 #include "miscadmin.h"
@@ -959,18 +960,25 @@ CommitTransaction(void)
 	s->state = TRANS_COMMIT;
 
 	/*
-	 * do commit processing
+	 * Do pre-commit processing (most of this stuff requires database
+	 * access, and in fact could still cause an error...)
 	 */
 
+	AtEOXact_portals();
+
 	/* handle commit for large objects [ PA, 7/17/98 ] */
+	/* XXX probably this does not belong here */
 	lo_commit(true);
 
-	/* NOTIFY commit must also come before lower-level cleanup */
+	/* NOTIFY commit must come before lower-level cleanup */
 	AtCommit_Notify();
 
-	AtEOXact_portals();
+	/* Update the flat password file if we changed pg_shadow or pg_group */
+	AtEOXact_UpdatePasswordFile(true);
 
-	/* Here is where we really truly commit. */
+	/*
+	 * Here is where we really truly commit.
+	 */
 	RecordTransactionCommit();
 
 	/*
@@ -1013,7 +1021,6 @@ CommitTransaction(void)
 	AtEOXact_CatCache(true);
 	AtCommit_Memory();
 	AtEOXact_Buffers(true);
-	smgrabort();
 	AtEOXact_Files();
 
 	/* Count transaction commit in statistics collector */
@@ -1080,9 +1087,10 @@ AbortTransaction(void)
 	 * do abort processing
 	 */
 	DeferredTriggerAbortXact();
+	AtEOXact_portals();
 	lo_commit(false);			/* 'false' means it's abort */
 	AtAbort_Notify();
-	AtEOXact_portals();
+	AtEOXact_UpdatePasswordFile(false);
 
 	/* Advertise the fact that we aborted in pg_clog. */
 	RecordTransactionAbort();
@@ -1114,6 +1122,7 @@ AbortTransaction(void)
 	AtEOXact_CatCache(false);
 	AtAbort_Memory();
 	AtEOXact_Buffers(false);
+	smgrabort();
 	AtEOXact_Files();
 	AtAbort_Locks();
 

src/include/commands/user.h

 /*-------------------------------------------------------------------------
  *
  * user.h
+ *	  Commands for manipulating users and groups.
  *
  *
- * $Id: user.h,v 1.19 2002/09/04 20:31:42 momjian Exp $
+ * $Id: user.h,v 1.20 2002/10/21 19:46:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -13,13 +14,10 @@
 #include "fmgr.h"
 #include "nodes/parsenodes.h"
 
-#define PWD_FILE	"pg_pwd"
-
-#define USER_GROUP_FILE "pg_group"
-
 
 extern char *group_getfilename(void);
 extern char *user_getfilename(void);
+
 extern void CreateUser(CreateUserStmt *stmt);
 extern void AlterUser(AlterUserStmt *stmt);
 extern void AlterUserSet(AlterUserSetStmt *stmt);
@@ -31,4 +29,6 @@ extern void DropGroup(DropGroupStmt *stmt);
 
 extern Datum update_pg_pwd_and_pg_group(PG_FUNCTION_ARGS);
 
+extern void AtEOXact_UpdatePasswordFile(bool isCommit);
+
 #endif   /* USER_H */