* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.376 2010/02/19 01:04:03 itagaki Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.377 2010/02/19 10:51:03 heikki Exp $
*
*-------------------------------------------------------------------------
*/
* WAL segment files will not be re-read in normal operation, so we advise
* the OS to release any cached pages. But do not do so if WAL archiving
* or streaming is active, because archiver and walsender process could use
- * the cache to read the WAL segment. Also, don't bother with it if we
- * are using O_DIRECT, since the kernel is presumably not caching in that
- * case.
+ * the cache to read the WAL segment.
*/
#if defined(USE_POSIX_FADVISE) && defined(POSIX_FADV_DONTNEED)
- if (!XLogIsNeeded() &&
- (get_sync_bit(sync_method) & PG_O_DIRECT) == 0)
+ if (!XLogIsNeeded())
(void) posix_fadvise(openLogFile, 0, 0, POSIX_FADV_DONTNEED);
#endif
static int
get_sync_bit(int method)
{
+ int o_direct_flag = 0;
+
/* If fsync is disabled, never open in sync mode */
if (!enableFsync)
return 0;
+ /*
+ * Optimize writes by bypassing kernel cache with O_DIRECT when using
+ * O_SYNC, O_DSYNC or O_FSYNC. But only if archiving and streaming are
+ * disabled, otherwise the archive command or walsender process will
+ * read the WAL soon after writing it, which is guaranteed to cause a
+ * physical read if we bypassed the kernel cache. We also skip the
+ * posix_fadvise(POSIX_FADV_DONTNEED) call in XLogFileClose() for the
+ * same reason.
+ *
+ * Never use O_DIRECT in walreceiver process for similar reasons; the WAL
+ * written by walreceiver is normally read by the startup process soon
+ * after its written. Also, walreceiver performs unaligned writes, which
+ * don't work with O_DIRECT, so it is required for correctness too.
+ */
+ if (!XLogIsNeeded() && !am_walreceiver)
+ o_direct_flag = PG_O_DIRECT;
+
switch (method)
{
/*
return 0;
#ifdef OPEN_SYNC_FLAG
case SYNC_METHOD_OPEN:
- return OPEN_SYNC_FLAG;
+ return OPEN_SYNC_FLAG | o_direct_flag;
#endif
#ifdef OPEN_DATASYNC_FLAG
case SYNC_METHOD_OPEN_DSYNC:
- return OPEN_DATASYNC_FLAG;
+ return OPEN_DATASYNC_FLAG | o_direct_flag;
#endif
default:
/* can't happen (unless we are out of sync with option array) */
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/replication/walreceiver.c,v 1.4 2010/02/17 04:19:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/replication/walreceiver.c,v 1.5 2010/02/19 10:51:04 heikki Exp $
*
*-------------------------------------------------------------------------
*/
#include "utils/ps_status.h"
#include "utils/resowner.h"
+/* Global variable to indicate if this process is a walreceiver process */
+bool am_walreceiver;
+
/* libpqreceiver hooks to these when loaded */
walrcv_connect_type walrcv_connect = NULL;
walrcv_receive_type walrcv_receive = NULL;
/* use volatile pointer to prevent code rearrangement */
volatile WalRcvData *walrcv = WalRcv;
+ am_walreceiver = true;
+
/*
* WalRcv should be set up already (if we are a backend, we inherit
* this by fork() or EXEC_BACKEND mechanism from the postmaster).
bool use_existent;
/*
- * XLOG segment files will be re-read in recovery operation soon,
- * so we don't need to advise the OS to release any cache page.
+ * fsync() and close current file before we switch to next one.
+ * We would otherwise have to reopen this file to fsync it later
*/
if (recvFile >= 0)
{
+ XLogWalRcvFlush();
+
/*
- * fsync() before we switch to next file. We would otherwise
- * have to reopen this file to fsync it later
+ * XLOG segment files will be re-read by recovery in startup
+ * process soon, so we don't advise the OS to release cache
+ * pages associated with the file like XLogFileClose() does.
*/
- XLogWalRcvFlush();
if (close(recvFile) != 0)
ereport(PANIC,
(errcode_for_file_access(),
/* Create/use new log file */
XLByteToSeg(recptr, recvId, recvSeg);
use_existent = true;
- recvFile = XLogFileInit(recvId, recvSeg,
- &use_existent, true);
+ recvFile = XLogFileInit(recvId, recvSeg, &use_existent, true);
recvOff = 0;
}
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/access/xlogdefs.h,v 1.25 2010/01/15 09:19:06 heikki Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlogdefs.h,v 1.26 2010/02/19 10:51:04 heikki Exp $
*/
#ifndef XLOG_DEFS_H
#define XLOG_DEFS_H
* configure determined whether fdatasync() is.
*/
#if defined(O_SYNC)
-#define BARE_OPEN_SYNC_FLAG O_SYNC
+#define OPEN_SYNC_FLAG O_SYNC
#elif defined(O_FSYNC)
-#define BARE_OPEN_SYNC_FLAG O_FSYNC
-#endif
-#ifdef BARE_OPEN_SYNC_FLAG
-#define OPEN_SYNC_FLAG (BARE_OPEN_SYNC_FLAG | PG_O_DIRECT)
+#define OPEN_SYNC_FLAG O_FSYNC
#endif
#if defined(O_DSYNC)
#if defined(OPEN_SYNC_FLAG)
/* O_DSYNC is distinct? */
-#if O_DSYNC != BARE_OPEN_SYNC_FLAG
-#define OPEN_DATASYNC_FLAG (O_DSYNC | PG_O_DIRECT)
+#if O_DSYNC != OPEN_SYNC_FLAG
+#define OPEN_DATASYNC_FLAG O_DSYNC
#endif
#else /* !defined(OPEN_SYNC_FLAG) */
/* Win32 only has O_DSYNC */
-#define OPEN_DATASYNC_FLAG (O_DSYNC | PG_O_DIRECT)
+#define OPEN_DATASYNC_FLAG O_DSYNC
#endif
#endif
*
* Portions Copyright (c) 2010-2010, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/include/replication/walreceiver.h,v 1.6 2010/02/03 09:47:19 heikki Exp $
+ * $PostgreSQL: pgsql/src/include/replication/walreceiver.h,v 1.7 2010/02/19 10:51:04 heikki Exp $
*
*-------------------------------------------------------------------------
*/
#include "access/xlogdefs.h"
#include "storage/spin.h"
+extern bool am_walreceiver;
+
/*
* MAXCONNINFO: maximum size of a connection string.
*
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