From 4a78cdeb6b598940e9d9adb92deca6494628802a Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 1 Aug 2007 22:45:09 +0000
Subject: Support an optional asynchronous commit mode, in which we don't flush
 WAL before reporting a transaction committed.  Data consistency is still
 guaranteed (unlike setting fsync = off), but a crash may lose the effects of
 the last few transactions.  Patch by Simon, some editorialization by Tom.

---
 src/backend/utils/misc/guc.c                  | 14 +++++++++++---
 src/backend/utils/misc/postgresql.conf.sample |  1 +
 2 files changed, 12 insertions(+), 3 deletions(-)

(limited to 'src/backend/utils/misc')

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index b2d0ea9cae5..c30d8b50a05 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.407 2007/07/24 04:54:09 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.408 2007/08/01 22:45:09 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -553,6 +553,14 @@ static struct config_bool ConfigureNamesBool[] =
 		&enableFsync,
 		true, NULL, NULL
 	},
+	{
+		{"synchronous_commit", PGC_USERSET, WAL_SETTINGS,
+			gettext_noop("Sets immediate fsync at commit."),
+			NULL
+		},
+		&XactSyncCommit,
+		true, NULL, NULL
+	},
 	{
 		{"zero_damaged_pages", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Continues processing past damaged page headers."),
@@ -1521,7 +1529,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"commit_delay", PGC_USERSET, WAL_CHECKPOINTS,
+		{"commit_delay", PGC_USERSET, WAL_SETTINGS,
 			gettext_noop("Sets the delay in microseconds between transaction commit and "
 						 "flushing WAL to disk."),
 			NULL
@@ -1531,7 +1539,7 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	{
-		{"commit_siblings", PGC_USERSET, WAL_CHECKPOINTS,
+		{"commit_siblings", PGC_USERSET, WAL_SETTINGS,
 			gettext_noop("Sets the minimum concurrent open transactions before performing "
 						 "commit_delay."),
 			NULL
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 8bfad997ff3..c87e4baf43d 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -149,6 +149,7 @@
 # - Settings -
 
 #fsync = on				# turns forced synchronization on or off
+#synchronous_commit = on		# immediate fsync at commit
 #wal_sync_method = fsync		# the default is the first option 
 					# supported by the operating system:
 					#   open_datasync
-- 
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