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authorTom Lane <tgl@sss.pgh.pa.us>2010-12-08 20:01:09 -0500
committerTom Lane <tgl@sss.pgh.pa.us>2010-12-08 20:01:09 -0500
commit576477e73c4a9cb32c7471c1cec354fd5328140e (patch)
tree57f198feef6d233848f9aebc2f3c2a2c51d473ff /src/include/access/xlogdefs.h
parente620ee35b249b0af255ef788003d1c9edb815a35 (diff)
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/include/access/xlogdefs.h')
-rw-r--r--src/include/access/xlogdefs.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/src/include/access/xlogdefs.h b/src/include/access/xlogdefs.h
index 18b214e992a..072096ddff5 100644
--- a/src/include/access/xlogdefs.h
+++ b/src/include/access/xlogdefs.h
@@ -123,12 +123,12 @@ typedef uint32 TimeLineID;
#endif
#endif
-#if defined(OPEN_DATASYNC_FLAG)
+#if defined(PLATFORM_DEFAULT_SYNC_METHOD)
+#define DEFAULT_SYNC_METHOD PLATFORM_DEFAULT_SYNC_METHOD
+#elif defined(OPEN_DATASYNC_FLAG)
#define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN_DSYNC
#elif defined(HAVE_FDATASYNC)
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC
-#elif defined(HAVE_FSYNC_WRITETHROUGH_ONLY)
-#define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC_WRITETHROUGH
#else
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC
#endif