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Postgres FD Implementation
Commit 0d9e0d9d authored by Bruce Momjian's avatar Bruce Momjian
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Copy fsync() defines into test_fsync.c, someday place them in an 

include.

Propery align for O_DIRECT.

Check for write()/fsync() failures.
parent f14d43d2
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Showing with 136 additions and 41 deletions
src/tools/fsync/test_fsync.c
View file @ 0d9e0d9d
/*
* test_fsync.c
* tests if fsync can be done from another process than the original write
* test various fsync() methods
*/
#include "../../include/pg_config.h"
#include "../../include/pg_config_os.h"
#include "postgres.h"
#include "access/xlog_internal.h"
#include "access/xlog.h"
#include <sys/types.h>
#include <sys/stat.h>
......@@ -14,29 +16,94 @@
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#ifdef WIN32
#define FSYNC_FILENAME "./test_fsync.out"
/* ---------------------------------------------------------------
* Copied from xlog.c. Some day this should be moved an include file.
*/
/*
* 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 FSYNC_FILENAME "/var/tmp/test_fsync.out"
#define PG_O_DIRECT 0
#endif
/* O_SYNC and O_FSYNC are the same */
/*
* 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 OPEN_SYNC_FLAG O_SYNC
#define BARE_OPEN_SYNC_FLAG O_SYNC
#elif defined(O_FSYNC)
#define OPEN_SYNC_FLAG O_FSYNC
#elif defined(O_DSYNC)
#define OPEN_DATASYNC_FLAG O_DSYNC
#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)
#if defined(O_DSYNC) && (O_DSYNC != OPEN_SYNC_FLAG)
#define OPEN_DATASYNC_FLAG O_DSYNC
/* 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
/* ------------ from xlog.c --------------- */
#ifdef WIN32
#define FSYNC_FILENAME "./test_fsync.out"
#else
/* /tmp might be a memory file system */
#define FSYNC_FILENAME "/var/tmp/test_fsync.out"
#endif
#define WAL_FILE_SIZE (16 * 1024 * 1024)
#define WRITE_SIZE (16 * 1024)
void die(char *str);
void print_elapse(struct timeval start_t, struct timeval elapse_t);
......@@ -49,7 +116,7 @@ main(int argc, char *argv[])
int tmpfile,
i,
loops = 1000;
char *strout = (char *) malloc(WAL_FILE_SIZE);
char *full_buf = (char *) malloc(XLOG_SEG_SIZE), *buf;
char *filename = FSYNC_FILENAME;
if (argc > 2 && strcmp(argv[1], "-f") == 0)
......@@ -62,15 +129,20 @@ main(int argc, char *argv[])
if (argc > 1)
loops = atoi(argv[1]);
for (i = 0; i < WAL_FILE_SIZE; i++)
strout[i] = 'a';
for (i = 0; i < XLOG_SEG_SIZE; i++)
full_buf[i] = 'a';
if ((tmpfile = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) == -1)
die("Cannot open output file.");
write(tmpfile, strout, WAL_FILE_SIZE);
fsync(tmpfile); /* fsync so later fsync's don't have to do it */
if (write(tmpfile, full_buf, XLOG_SEG_SIZE) != XLOG_SEG_SIZE)
die("write failed");
/* fsync so later fsync's don't have to do it */
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
buf = (char *)TYPEALIGN(ALIGNOF_XLOG_BUFFER, full_buf);
printf("Simple write timing:\n");
/* write only */
gettimeofday(&start_t, NULL);
......@@ -78,7 +150,8 @@ main(int argc, char *argv[])
{
if ((tmpfile = open(filename, O_RDWR)) == -1)
die("Cannot open output file.");
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
close(tmpfile);
}
gettimeofday(&elapse_t, NULL);
......@@ -95,8 +168,10 @@ main(int argc, char *argv[])
{
if ((tmpfile = open(filename, O_RDWR)) == -1)
die("Cannot open output file.");
write(tmpfile, strout, 8192);
fsync(tmpfile);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
if ((tmpfile = open(filename, O_RDWR)) == -1)
die("Cannot open output file.");
......@@ -114,12 +189,14 @@ main(int argc, char *argv[])
{
if ((tmpfile = open(filename, O_RDWR)) == -1)
die("Cannot open output file.");
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
close(tmpfile);
/* reopen file */
if ((tmpfile = open(filename, O_RDWR)) == -1)
die("Cannot open output file.");
fsync(tmpfile);
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
}
gettimeofday(&elapse_t, NULL);
......@@ -135,7 +212,8 @@ main(int argc, char *argv[])
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
write(tmpfile, strout, 16384);
if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\tone 16k o_sync write ");
......@@ -148,8 +226,10 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
......@@ -169,7 +249,8 @@ main(int argc, char *argv[])
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_dsync, write ");
......@@ -181,7 +262,8 @@ main(int argc, char *argv[])
die("Cannot open output file.");
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
gettimeofday(&elapse_t, NULL);
close(tmpfile);
printf("\topen o_sync, write ");
......@@ -199,7 +281,8 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
fdatasync(tmpfile);
}
gettimeofday(&elapse_t, NULL);
......@@ -217,8 +300,10 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
fsync(tmpfile);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
......@@ -235,8 +320,10 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
......@@ -254,8 +341,10 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
......@@ -271,8 +360,10 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
write(tmpfile, strout, 8192);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
fdatasync(tmpfile);
}
gettimeofday(&elapse_t, NULL);
......@@ -290,9 +381,12 @@ main(int argc, char *argv[])
gettimeofday(&start_t, NULL);
for (i = 0; i < loops; i++)
{
write(tmpfile, strout, 8192);
write(tmpfile, strout, 8192);
fsync(tmpfile);
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (write(tmpfile, buf, WRITE_SIZE/2) != WRITE_SIZE/2)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
}
gettimeofday(&elapse_t, NULL);
close(tmpfile);
......@@ -300,6 +394,7 @@ main(int argc, char *argv[])
print_elapse(start_t, elapse_t);
printf("\n");
free(full_buf);
unlink(filename);
return 0;
......
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