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Move fsync method macro defines into /include/access/xlogdefs.h so they

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can be used by src/tools/fsync/test_fsync.c.
This commit is contained in:
Bruce Momjian
2007-02-14 05:00:40 +00:00
parent 5c63829f2f
commit a9eb53969a
3 changed files with 75 additions and 151 deletions
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73
src/include/access/xlogdefs.h
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@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/xlogdefs.h,v 1.16 2007/01/05 22:19:51 momjian Exp $
* $PostgreSQL: pgsql/src/include/access/xlogdefs.h,v 1.17 2007/02/14 05:00:40 momjian Exp $
*/
#ifndef XLOG_DEFS_H
#define XLOG_DEFS_H
@@ -63,4 +63,75 @@ typedef struct XLogRecPtr
*/
typedef uint32 TimeLineID;
/*
* Because O_DIRECT bypasses the kernel buffers, and because we never
* read those buffers except during crash recovery, it is a win to use
* it in all cases where we sync on each write(). We could allow O_DIRECT
* with fsync(), but because skipping the kernel buffer forces writes out
* quickly, it seems best just to use it for O_SYNC. It is hard to imagine
* how fsync() could be a win for O_DIRECT compared to O_SYNC and O_DIRECT.
* Also, O_DIRECT is never enough to force data to the drives, it merely
* tries to bypass the kernel cache, so we still need O_SYNC or fsync().
*/
#ifdef O_DIRECT
#define PG_O_DIRECT O_DIRECT
#else
#define PG_O_DIRECT 0
#endif
/*
* This chunk of hackery attempts to determine which file sync methods
* are available on the current platform, and to choose an appropriate
* default method. We assume that fsync() is always available, and that
* configure determined whether fdatasync() is.
*/
#if defined(O_SYNC)
#define BARE_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)
#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)
#endif
#else /* !defined(OPEN_SYNC_FLAG) */
/* Win32 only has O_DSYNC */
#define OPEN_DATASYNC_FLAG (O_DSYNC | PG_O_DIRECT)
#endif
#endif
#if defined(OPEN_DATASYNC_FLAG)
#define DEFAULT_SYNC_METHOD_STR "open_datasync"
#define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN
#define DEFAULT_SYNC_FLAGBIT OPEN_DATASYNC_FLAG
#elif defined(HAVE_FDATASYNC)
#define DEFAULT_SYNC_METHOD_STR "fdatasync"
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC
#define DEFAULT_SYNC_FLAGBIT 0
#elif defined(HAVE_FSYNC_WRITETHROUGH_ONLY)
#define DEFAULT_SYNC_METHOD_STR "fsync_writethrough"
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC_WRITETHROUGH
#define DEFAULT_SYNC_FLAGBIT 0
#else
#define DEFAULT_SYNC_METHOD_STR "fsync"
#define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC
#define DEFAULT_SYNC_FLAGBIT 0
#endif
/*
* Limitation of buffer-alignment for direct IO depends on OS and filesystem,
* but XLOG_BLCKSZ is assumed to be enough for it.
*/
#ifdef O_DIRECT
#define ALIGNOF_XLOG_BUFFER XLOG_BLCKSZ
#else
#define ALIGNOF_XLOG_BUFFER ALIGNOF_BUFFER
#endif
#endif /* XLOG_DEFS_H */