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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2010-12-08 20:01:19 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2010-12-08 20:01:19 -0500 |
| commit | f3224e010dbd372a5411c5ddf0aae27f35007b65 (patch) | |
| tree | d2862e387b88cefaf4b66f7cb97eaa809f0e12e2 /src/backend | |
| parent | 234ad01f9ea08514b1368bbf214e6c779e372a1a (diff) | |
| download | postgresql-f3224e010dbd372a5411c5ddf0aae27f35007b65.tar.gz postgresql-f3224e010dbd372a5411c5ddf0aae27f35007b65.zip | |
Force default wal_sync_method to be fdatasync on Linux.
Recent versions of the Linux system header files cause xlogdefs.h to
believe that open_datasync should be the default sync method, whereas
formerly fdatasync was the default on Linux. open_datasync is a bad
choice, first because it doesn't actually outperform fdatasync (in fact
the reverse), and second because we try to use O_DIRECT with it, causing
failures on certain filesystems (e.g., ext4 with data=journal option).
This part of the patch is largely per a proposal from Marti Raudsepp.
More extensive changes are likely to follow in HEAD, but this is as much
change as we want to back-patch.
Also clean up confusing code and incorrect documentation surrounding the
fsync_writethrough option. Those changes shouldn't result in any actual
behavioral change, but I chose to back-patch them anyway to keep the
branches looking similar in this area.
In 9.0 and HEAD, also do some copy-editing on the WAL Reliability
documentation section.
Back-patch to all supported branches, since any of them might get used
on modern Linux versions.
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/storage/file/fd.c | 9 | ||||
| -rw-r--r-- | src/backend/utils/misc/postgresql.conf.sample | 2 |
2 files changed, 6 insertions, 5 deletions
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c index 7acc72f0d4b..5b7e60a4fd9 100644 --- a/src/backend/storage/file/fd.c +++ b/src/backend/storage/file/fd.c @@ -256,12 +256,13 @@ static void RemovePgTempFilesInDir(const char *tmpdirname); int pg_fsync(int fd) { -#ifndef HAVE_FSYNC_WRITETHROUGH_ONLY - if (sync_method != SYNC_METHOD_FSYNC_WRITETHROUGH) - return pg_fsync_no_writethrough(fd); + /* #if is to skip the sync_method test if there's no need for it */ +#if defined(HAVE_FSYNC_WRITETHROUGH) && !defined(FSYNC_WRITETHROUGH_IS_FSYNC) + if (sync_method == SYNC_METHOD_FSYNC_WRITETHROUGH) + return pg_fsync_writethrough(fd); else #endif - return pg_fsync_writethrough(fd); + return pg_fsync_no_writethrough(fd); } diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index fabfc75f55d..ae839c634f6 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -153,7 +153,7 @@ #wal_sync_method = fsync # the default is the first option # supported by the operating system: # open_datasync - # fdatasync + # fdatasync (default on Linux) # fsync # fsync_writethrough # open_sync |