Restructure local-buffer handling per recent pghackers discussion.

The local buffer manager is no longer used for newly-created relations
(unless they are TEMP); a new non-TEMP relation goes through the shared
bufmgr and thus will participate normally in checkpoints.  But TEMP relations
use the local buffer manager throughout their lifespan.  Also, operations
in TEMP relations are not logged in WAL, thus improving performance.
Since it's no longer necessary to fsync relations as they move out of the
local buffers into shared buffers, quite a lot of smgr.c/md.c/fd.c code
is no longer needed and has been removed: there's no concept of a dirty
relation anymore in md.c/fd.c, and we never fsync anything but WAL.
Still TODO: improve local buffer management algorithms so that it would
be reasonable to increase NLocBuffer.

1 files changed, 13 insertions, 5 deletions

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 872722b856c..fbe61e5691c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.100 2002/08/05 01:24:13 thomas Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/transam/xlog.c,v 1.101 2002/08/06 02:36:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -136,11 +136,20 @@ bool		InRecovery = false;
  * to be set true.  The latter can be used to test whether the current xact
  * made any loggable changes (including out-of-xact changes, such as
  * sequence updates).
+ *
+ * When we insert/update/delete a tuple in a temporary relation, we do not
+ * make any XLOG record, since we don't care about recovering the state of
+ * the temp rel after a crash.  However, we will still need to remember
+ * whether our transaction committed or aborted in that case.  So, we must
+ * set MyXactMadeTempRelUpdate true to indicate that the XID will be of
+ * interest later.
  */
 XLogRecPtr	MyLastRecPtr = {0, 0};
 
 bool		MyXactMadeXLogEntry = false;
 
+bool		MyXactMadeTempRelUpdate = false;
+
 /*
  * ProcLastRecPtr points to the start of the last XLOG record inserted by the
  * current backend.  It is updated for all inserts, transaction-controlled
@@ -2923,6 +2932,7 @@ ShutdownXLOG(void)
 	/* suppress in-transaction check in CreateCheckPoint */
 	MyLastRecPtr.xrecoff = 0;
 	MyXactMadeXLogEntry = false;
+	MyXactMadeTempRelUpdate = false;
 
 	CritSectionCount++;
 	CreateDummyCaches();
@@ -3084,12 +3094,10 @@ CreateCheckPoint(bool shutdown)
 
 	/*
 	 * Having constructed the checkpoint record, ensure all shmem disk
-	 * buffers are flushed to disk.
+	 * buffers and commit-log buffers are flushed to disk.
 	 */
-	FlushBufferPool();
-
-	/* And commit-log buffers, too */
 	CheckPointCLOG();
+	FlushBufferPool();
 
 	/*
 	 * Now insert the checkpoint record into XLOG.