diff --git a/src/tools/fsync/Makefile b/src/tools/fsync/Makefile
index fe3e626223..44419eef49 100644
--- a/src/tools/fsync/Makefile
+++ b/src/tools/fsync/Makefile
@@ -16,9 +16,9 @@ override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
OBJS= test_fsync.o
-all: test_fsync
+all: submake-libpq submake-libpgport test_fsync
-test_fsync: test_fsync.o | submake-libpq submake-libpgport
+test_fsync: test_fsync.o $(libpq_builddir)/libpq.a
$(CC) $(CFLAGS) test_fsync.o $(libpq_pgport) $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
clean distclean maintainer-clean:
diff --git a/src/tools/fsync/README b/src/tools/fsync/README
index 6d9acd333f..a1c2ae4594 100644
--- a/src/tools/fsync/README
+++ b/src/tools/fsync/README
@@ -1,11 +1,20 @@
-src/tools/fsync/README
-
-fsync
-=====
+test_fsync
+==========
This program tests fsync. The tests are described as part of the program output.
Usage: test_fsync [-f filename] [loops]
+
+test_fsync is intended to give you a reasonable idea of what the fastest
+fsync_method is on your specific system, as well as supplying diagnostic
+information in the event of an identified I/O problem. However,
+differences shown by test_fsync might not make any difference in real
+database throughput, especially since many database servers are not
+speed-limited by their transaction logs.
+
+The output filename defaults to test_fsync.out in the current directory.
+test_fsync should be run in the same filesystem as your transaction log
+directory (pg_xlog).
+
+Loops default to 2000. Increase this to get more accurate measurements.
-Loops defaults to 5000. The default output file is /var/tmp/test_fsync.out.
-Consider that /tmp or /var/tmp might be memory-based file systems.
diff --git a/src/tools/fsync/test_fsync.c b/src/tools/fsync/test_fsync.c
index 28c211929e..831e2a008f 100644
--- a/src/tools/fsync/test_fsync.c
+++ b/src/tools/fsync/test_fsync.c
@@ -3,7 +3,7 @@
*
*
* test_fsync.c
- * test various fsync() methods
+ * tests all supported fsync() methods
*/
#include "postgres.h"
@@ -22,19 +22,18 @@
#include <unistd.h>
#include <string.h>
-
-#ifdef WIN32
+/*
+ * put the temp files in the local directory
+ * unless the user specifies otherwise
+ */
#define FSYNC_FILENAME "./test_fsync.out"
-#else
-/* /tmp might be a memory file system */
-#define FSYNC_FILENAME "/var/tmp/test_fsync.out"
-#endif
#define WRITE_SIZE (8 * 1024) /* 8k */
#define LABEL_FORMAT "\t%-30s"
-int loops = 10000;
+
+int loops = 2000;
void die(char *str);
void print_elapse(struct timeval start_t, struct timeval stop_t);
@@ -42,14 +41,14 @@ void print_elapse(struct timeval start_t, struct timeval stop_t);
int
main(int argc, char *argv[])
{
- struct timeval start_t;
- struct timeval stop_t;
- int tmpfile,
- i;
+ struct timeval start_t, stop_t;
+ int tmpfile, i;
char *full_buf = (char *) malloc(XLOG_SEG_SIZE),
- *buf;
- char *filename = FSYNC_FILENAME;
+ *buf, *filename = FSYNC_FILENAME;
+ /*
+ * arguments: loops and filename (optional)
+ */
if (argc > 2 && strcmp(argv[1], "-f") == 0)
{
filename = argv[2];
@@ -57,17 +56,22 @@ main(int argc, char *argv[])
argc -= 2;
}
- if (argc > 1)
+ if (argc > 1)
loops = atoi(argv[1]);
for (i = 0; i < XLOG_SEG_SIZE; i++)
full_buf[i] = random();
+ /*
+ * test if we can open the target file
+ */
if ((tmpfile = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) == -1)
die("Cannot open output file.");
if (write(tmpfile, full_buf, XLOG_SEG_SIZE) != XLOG_SEG_SIZE)
die("write failed");
- /* fsync now so later fsync's don't have to do it */
+ /*
+ * fsync now so that dirty buffers don't skew later tests
+ */
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
@@ -77,7 +81,7 @@ main(int argc, char *argv[])
printf("Loops = %d\n\n", loops);
/*
- * Simple write
+ * Test a simple write without fsync
*/
printf("Simple write:\n");
printf(LABEL_FORMAT, "8k write");
@@ -95,10 +99,13 @@ main(int argc, char *argv[])
print_elapse(start_t, stop_t);
/*
- * Compare file sync methods with one 8k write
+ * Test all fsync methods using single 8k writes
*/
printf("\nCompare file sync methods using one write:\n");
+ /*
+ * Test open_datasync if available
+ */
#ifdef OPEN_DATASYNC_FLAG
printf(LABEL_FORMAT, "open_datasync 8k write");
fflush(stdout);
@@ -115,10 +122,40 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+ /*
+ * If O_DIRECT is enabled, test that with open_datasync
+ */
+#if PG_O_DIRECT != 0
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
+ printf("\t(unavailable: o_direct on this filesystem)\n");
+ else
+ {
+ printf(LABEL_FORMAT, "open_datasync 8k direct I/O write");
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+ }
+#else
+ printf("\t(unavailable: o_direct)\n");
+#endif
+
#else
printf("\t(unavailable: open_datasync)\n");
#endif
+/*
+ * Test open_sync if available
+ */
#ifdef OPEN_SYNC_FLAG
printf(LABEL_FORMAT, "open_sync 8k write");
fflush(stdout);
@@ -135,10 +172,40 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+ /*
+ * If O_DIRECT is enabled, test that with open_sync
+ */
+#if PG_O_DIRECT != 0
+ printf(LABEL_FORMAT, "open_sync 8k direct I/O write");
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
+ printf("\t(unavailable: o_direct on this filesystem)\n");
+ else
+ {
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+ }
+#else
+ printf("\t(unavailable: o_direct)\n");
+#endif
+
#else
printf("\t(unavailable: open_sync)\n");
#endif
+/*
+ * Test fdatasync if available
+ */
#ifdef HAVE_FDATASYNC
printf(LABEL_FORMAT, "8k write, fdatasync");
fflush(stdout);
@@ -160,6 +227,9 @@ main(int argc, char *argv[])
printf("\t(unavailable: fdatasync)\n");
#endif
+/*
+ * Test fsync
+ */
printf(LABEL_FORMAT, "8k write, fsync");
fflush(stdout);
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
@@ -177,14 +247,43 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+/*
+ * If fsync_writethrough is available, test as well
+ */
+#ifdef HAVE_FSYNC_WRITETHROUGH
+ printf(LABEL_FORMAT, "8k write, fsync_writethrough");
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+ die("Cannot open output file.");
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (fcntl(tmpfile, F_FULLFSYNC ) != 0)
+ die("fsync failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+#else
+ printf("\t(unavailable: fsync_writethrough)\n");
+#endif
/*
- * Compare file sync methods with two 8k write
+ * Compare some of the file sync methods with
+ * two 8k writes to see if timing is different
*/
printf("\nCompare file sync methods using two writes:\n");
+/*
+ * Test open_datasync with and without o_direct
+ */
#ifdef OPEN_DATASYNC_FLAG
- printf(LABEL_FORMAT, "2 open_datasync 8k writes");
+ printf(LABEL_FORMAT, "2 open_datasync 8k writes");
fflush(stdout);
if ((tmpfile = open(filename, O_RDWR | O_DSYNC, 0)) == -1)
die("Cannot open output file.");
@@ -201,10 +300,36 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+#if PG_O_DIRECT != 0
+ printf(LABEL_FORMAT, "2 open_datasync direct I/O 8k writes");
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
+ die("Cannot open output file.");
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+#else
+ printf("\t(unavailable: o_direct)\n");
+#endif
+
#else
printf("\t(unavailable: open_datasync)\n");
#endif
+/*
+ * Test open_sync with and without o_direct
+ */
#ifdef OPEN_SYNC_FLAG
printf(LABEL_FORMAT, "2 open_sync 8k writes");
fflush(stdout);
@@ -223,8 +348,36 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+#if PG_O_DIRECT != 0
+ printf(LABEL_FORMAT, "2 open_sync direct I/O 8k writes");
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
+ die("Cannot open output file.");
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+#else
+ printf("\t(unavailable: o_direct)\n");
#endif
+#else
+ printf("\t(unavailable: open_sync)\n");
+#endif
+
+/*
+ * Test fdatasync
+ */
#ifdef HAVE_FDATASYNC
printf(LABEL_FORMAT, "8k write, 8k write, fdatasync");
fflush(stdout);
@@ -248,6 +401,9 @@ main(int argc, char *argv[])
printf("\t(unavailable: fdatasync)\n");
#endif
+/*
+ * Test basic fsync
+ */
printf(LABEL_FORMAT, "8k write, 8k write, fsync");
fflush(stdout);
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
@@ -267,12 +423,44 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
close(tmpfile);
print_elapse(start_t, stop_t);
+
+/*
+ * Test fsync_writethrough if available
+ */
+#ifdef HAVE_FSYNC_WRITETHROUGH
+ printf(LABEL_FORMAT, "8k write, 8k write, fsync_writethrough");
+ fflush(stdout);
+ if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
+ die("Cannot open output file.");
+ gettimeofday(&start_t, NULL);
+ for (i = 0; i < loops; i++)
+ {
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (write(tmpfile, buf, WRITE_SIZE) != WRITE_SIZE)
+ die("write failed");
+ if (fcntl(tmpfile, F_FULLFSYNC) != 0)
+ die("fsync failed");
+ if (lseek(tmpfile, 0, SEEK_SET) == -1)
+ die("seek failed");
+ }
+ gettimeofday(&stop_t, NULL);
+ close(tmpfile);
+ print_elapse(start_t, stop_t);
+#else
+ printf("\t(unavailable: fsync_writethrough)\n");
+#endif
/*
* Compare 1 to 2 writes
*/
printf("\nCompare open_sync with different sizes:\n");
+ printf("(This is designed to compare the cost of one large\n");
+ printf("sync'ed write and two smaller sync'ed writes.)\n");
+/*
+ * Test open_sync with different size files
+ */
#ifdef OPEN_SYNC_FLAG
printf(LABEL_FORMAT, "open_sync 16k write");
fflush(stdout);
@@ -312,12 +500,20 @@ main(int argc, char *argv[])
#endif
/*
- * Fsync another file descriptor?
+ * Test whether fsync can sync data written on a different
+ * descriptor for the same file. This checks the efficiency
+ * of multi-process fsyncs against the same file.
+ * Possibly this should be done with writethrough on platforms
+ * which support it.
*/
printf("\nTest if fsync on non-write file descriptor is honored:\n");
printf("(If the times are similar, fsync() can sync data written\n");
printf("on a different descriptor.)\n");
+ /*
+ * first write, fsync and close, which is the
+ * normal behavior without multiple descriptors
+ */
printf(LABEL_FORMAT, "8k write, fsync, close");
fflush(stdout);
gettimeofday(&start_t, NULL);
@@ -330,14 +526,22 @@ main(int argc, char *argv[])
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
+ /*
+ * open and close the file again to be consistent
+ * with the following test
+ */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("Cannot open output file.");
- /* do nothing but the open/close the tests are consistent. */
close(tmpfile);
}
gettimeofday(&stop_t, NULL);
print_elapse(start_t, stop_t);
+ /*
+ * Now open, write, close, open again and fsync
+ * This simulates processes fsyncing each other's
+ * writes.
+ */
printf(LABEL_FORMAT, "8k write, close, fsync");
fflush(stdout);
gettimeofday(&start_t, NULL);
@@ -358,18 +562,22 @@ main(int argc, char *argv[])
gettimeofday(&stop_t, NULL);
print_elapse(start_t, stop_t);
- /* cleanup */
+ /*
+ * cleanup
+ */
free(full_buf);
unlink(filename);
return 0;
}
+/*
+ * print out the writes per second for tests
+ */
void
print_elapse(struct timeval start_t, struct timeval stop_t)
{
double total_time = (stop_t.tv_sec - start_t.tv_sec) +
- /* usec subtraction might be negative, e.g. 5.4 - 4.8 */
(stop_t.tv_usec - start_t.tv_usec) * 0.000001;
double per_second = loops / total_time;