Clean up backend-exit-time cleanup behavior. Use on_shmem_exit callbacks

to ensure that we have released buffer refcounts and so forth, rather than
putting ad-hoc operations before (some of the calls to) proc_exit.  Add
commentary to discourage future hackers from repeating that mistake.

2 files changed, 22 insertions, 20 deletions

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 6cd089fd959..c8c9e680f5f 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.88 2000/12/07 10:03:46 inoue Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.89 2000/12/18 00:44:45 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -1095,6 +1095,15 @@ AbortTransaction(void)
 		MyProc->xmin = InvalidTransactionId;
 	}
 
+	/*
+	 * Release any spinlocks or buffer context locks we might be holding
+	 * as quickly as possible.  (Real locks, however, must be held till
+	 * we finish aborting.)  Releasing spinlocks is critical since we
+	 * might try to grab them again while cleaning up!
+	 */
+	ProcReleaseSpins(NULL);
+	UnlockBuffers();
+
 	/* ----------------
 	 *	check the current transaction state
 	 * ----------------
@@ -1105,18 +1114,6 @@ AbortTransaction(void)
 	if (s->state != TRANS_INPROGRESS)
 		elog(NOTICE, "AbortTransaction and not in in-progress state");
 
-	/*
-	 * Reset user id which might have been changed transiently
-	 */
-	SetUserId(GetSessionUserId());
-
-	/* ----------------
-	 *	Tell the trigger manager that this transaction is about to be
-	 *	aborted.
-	 * ----------------
-	 */
-	DeferredTriggerAbortXact();
-
 	/* ----------------
 	 *	set the current transaction state information
 	 *	appropriately during the abort processing
@@ -1124,12 +1121,17 @@ AbortTransaction(void)
 	 */
 	s->state = TRANS_ABORT;
 
+	/*
+	 * Reset user id which might have been changed transiently
+	 */
+	SetUserId(GetSessionUserId());
+
 	/* ----------------
 	 *	do abort processing
 	 * ----------------
 	 */
+	DeferredTriggerAbortXact();
 	lo_commit(false);			/* 'false' means it's abort */
-	UnlockBuffers();
 	AtAbort_Notify();
 	CloseSequences();
 	AtEOXact_portals();
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 3b2c5461dcd..ba85f4b60d0 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.42 2000/12/11 19:27:42 vadim Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.43 2000/12/18 00:44:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -40,7 +40,7 @@
 
 int			XLOGbuffers = 8;
 XLogRecPtr	MyLastRecPtr = {0, 0};
-uint32		StopIfError = 0;
+uint32		CritSectionCount = 0;
 bool		InRecovery = false;
 StartUpID	ThisStartUpID = 0;
 
@@ -1531,7 +1531,7 @@ StartupXLOG()
 	char		buffer[MAXLOGRECSZ + SizeOfXLogRecord];
 
 	elog(LOG, "starting up");
-	StopIfError++;
+	CritSectionCount++;
 
 	XLogCtl->xlblocks = (XLogRecPtr *) (((char *) XLogCtl) + sizeof(XLogCtlData));
 	XLogCtl->pages = ((char *) XLogCtl->xlblocks + sizeof(XLogRecPtr) * XLOGbuffers);
@@ -1748,7 +1748,7 @@ StartupXLOG()
 	XLogCtl->ThisStartUpID = ThisStartUpID;
 
 	elog(LOG, "database system is in production state");
-	StopIfError--;
+	CritSectionCount--;
 
 	return;
 }
@@ -1771,10 +1771,10 @@ ShutdownXLOG()
 {
 	elog(LOG, "shutting down");
 
-	StopIfError++;
+	CritSectionCount++;
 	CreateDummyCaches();
 	CreateCheckPoint(true);
-	StopIfError--;
+	CritSectionCount--;
 
 	elog(LOG, "database system is shut down");
 }