postgresql/contrib/pg_test_fsync/pg_test_fsync.c
Robert Haas a016555361 Avoid file descriptor leak in pg_test_fsync.
This can cause problems on Windows, where files that are still open
can't be unlinked.

Jeff Janes
2014-11-19 12:06:24 -05:00

604 lines
13 KiB
C

/*
* pg_test_fsync.c
* tests all supported fsync() methods
*/
#include "postgres_fe.h"
#include <sys/stat.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include <signal.h>
#include "getopt_long.h"
#include "access/xlogdefs.h"
/*
* put the temp files in the local directory
* unless the user specifies otherwise
*/
#define FSYNC_FILENAME "./pg_test_fsync.out"
#define XLOG_BLCKSZ_K (XLOG_BLCKSZ / 1024)
#define LABEL_FORMAT " %-30s"
#define NA_FORMAT "%20s"
#define OPS_FORMAT "%13.3f ops/sec %6.0f usecs/op"
#define USECS_SEC 1000000
/* These are macros to avoid timing the function call overhead. */
#ifndef WIN32
#define START_TIMER \
do { \
alarm_triggered = false; \
alarm(secs_per_test); \
gettimeofday(&start_t, NULL); \
} while (0)
#else
/* WIN32 doesn't support alarm, so we create a thread and sleep there */
#define START_TIMER \
do { \
alarm_triggered = false; \
if (CreateThread(NULL, 0, process_alarm, NULL, 0, NULL) == \
INVALID_HANDLE_VALUE) \
{ \
fprintf(stderr, "Cannot create thread for alarm\n"); \
exit(1); \
} \
gettimeofday(&start_t, NULL); \
} while (0)
#endif
#define STOP_TIMER \
do { \
gettimeofday(&stop_t, NULL); \
print_elapse(start_t, stop_t, ops); \
} while (0)
static const char *progname;
static int secs_per_test = 5;
static int needs_unlink = 0;
static char full_buf[XLOG_SEG_SIZE],
*buf,
*filename = FSYNC_FILENAME;
static struct timeval start_t,
stop_t;
static bool alarm_triggered = false;
static void handle_args(int argc, char *argv[]);
static void prepare_buf(void);
static void test_open(void);
static void test_non_sync(void);
static void test_sync(int writes_per_op);
static void test_open_syncs(void);
static void test_open_sync(const char *msg, int writes_size);
static void test_file_descriptor_sync(void);
#ifndef WIN32
static void process_alarm(int sig);
#else
static DWORD WINAPI process_alarm(LPVOID param);
#endif
static void signal_cleanup(int sig);
#ifdef HAVE_FSYNC_WRITETHROUGH
static int pg_fsync_writethrough(int fd);
#endif
static void print_elapse(struct timeval start_t, struct timeval stop_t, int ops);
static void die(const char *str);
int
main(int argc, char *argv[])
{
progname = get_progname(argv[0]);
handle_args(argc, argv);
/* Prevent leaving behind the test file */
pqsignal(SIGINT, signal_cleanup);
pqsignal(SIGTERM, signal_cleanup);
#ifndef WIN32
pqsignal(SIGALRM, process_alarm);
#endif
#ifdef SIGHUP
/* Not defined on win32 */
pqsignal(SIGHUP, signal_cleanup);
#endif
prepare_buf();
test_open();
/* Test using 1 XLOG_BLCKSZ write */
test_sync(1);
/* Test using 2 XLOG_BLCKSZ writes */
test_sync(2);
test_open_syncs();
test_file_descriptor_sync();
test_non_sync();
unlink(filename);
return 0;
}
static void
handle_args(int argc, char *argv[])
{
static struct option long_options[] = {
{"filename", required_argument, NULL, 'f'},
{"secs-per-test", required_argument, NULL, 's'},
{NULL, 0, NULL, 0}
};
int option; /* Command line option */
int optindex = 0; /* used by getopt_long */
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
printf("Usage: %s [-f FILENAME] [-s SECS-PER-TEST]\n", progname);
exit(0);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
puts("pg_test_fsync (PostgreSQL) " PG_VERSION);
exit(0);
}
}
while ((option = getopt_long(argc, argv, "f:s:",
long_options, &optindex)) != -1)
{
switch (option)
{
case 'f':
filename = strdup(optarg);
break;
case 's':
secs_per_test = atoi(optarg);
break;
default:
fprintf(stderr, "Try \"%s --help\" for more information.\n",
progname);
exit(1);
break;
}
}
if (argc > optind)
{
fprintf(stderr,
"%s: too many command-line arguments (first is \"%s\")\n",
progname, argv[optind]);
fprintf(stderr, "Try \"%s --help\" for more information.\n",
progname);
exit(1);
}
printf("%d seconds per test\n", secs_per_test);
#if PG_O_DIRECT != 0
printf("O_DIRECT supported on this platform for open_datasync and open_sync.\n");
#else
printf("Direct I/O is not supported on this platform.\n");
#endif
}
static void
prepare_buf(void)
{
int ops;
/* write random data into buffer */
for (ops = 0; ops < XLOG_SEG_SIZE; ops++)
full_buf[ops] = random();
buf = (char *) TYPEALIGN(XLOG_BLCKSZ, full_buf);
}
static void
test_open(void)
{
int tmpfile;
/*
* test if we can open the target file
*/
if ((tmpfile = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR)) == -1)
die("could not open output file");
needs_unlink = 1;
if (write(tmpfile, full_buf, XLOG_SEG_SIZE) != XLOG_SEG_SIZE)
die("write failed");
/* fsync now so that dirty buffers don't skew later tests */
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
}
static void
test_sync(int writes_per_op)
{
int tmpfile,
ops,
writes;
bool fs_warning = false;
if (writes_per_op == 1)
printf("\nCompare file sync methods using one %dkB write:\n", XLOG_BLCKSZ_K);
else
printf("\nCompare file sync methods using two %dkB writes:\n", XLOG_BLCKSZ_K);
printf("(in wal_sync_method preference order, except fdatasync is Linux's default)\n");
/*
* Test open_datasync if available
*/
printf(LABEL_FORMAT, "open_datasync");
fflush(stdout);
#ifdef OPEN_DATASYNC_FLAG
if ((tmpfile = open(filename, O_RDWR | O_DSYNC | PG_O_DIRECT, 0)) == -1)
{
printf(NA_FORMAT, "n/a*\n");
fs_warning = true;
}
else
{
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
}
#else
printf(NA_FORMAT, "n/a\n");
#endif
/*
* Test fdatasync if available
*/
printf(LABEL_FORMAT, "fdatasync");
fflush(stdout);
#ifdef HAVE_FDATASYNC
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
fdatasync(tmpfile);
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
#else
printf(NA_FORMAT, "n/a\n");
#endif
/*
* Test fsync
*/
printf(LABEL_FORMAT, "fsync");
fflush(stdout);
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
if (fsync(tmpfile) != 0)
die("fsync failed");
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
/*
* If fsync_writethrough is available, test as well
*/
printf(LABEL_FORMAT, "fsync_writethrough");
fflush(stdout);
#ifdef HAVE_FSYNC_WRITETHROUGH
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
if (pg_fsync_writethrough(tmpfile) != 0)
die("fsync failed");
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
#else
printf(NA_FORMAT, "n/a\n");
#endif
/*
* Test open_sync if available
*/
printf(LABEL_FORMAT, "open_sync");
fflush(stdout);
#ifdef OPEN_SYNC_FLAG
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
{
printf(NA_FORMAT, "n/a*\n");
fs_warning = true;
}
else
{
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < writes_per_op; writes++)
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
/*
* This can generate write failures if the filesystem has
* a large block size, e.g. 4k, and there is no support
* for O_DIRECT writes smaller than the file system block
* size, e.g. XFS.
*/
die("write failed");
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
}
#else
printf(NA_FORMAT, "n/a\n");
#endif
if (fs_warning)
{
printf("* This file system and its mount options do not support direct\n");
printf("I/O, e.g. ext4 in journaled mode.\n");
}
}
static void
test_open_syncs(void)
{
printf("\nCompare open_sync with different write sizes:\n");
printf("(This is designed to compare the cost of writing 16kB in different write\n"
"open_sync sizes.)\n");
test_open_sync(" 1 * 16kB open_sync write", 16);
test_open_sync(" 2 * 8kB open_sync writes", 8);
test_open_sync(" 4 * 4kB open_sync writes", 4);
test_open_sync(" 8 * 2kB open_sync writes", 2);
test_open_sync("16 * 1kB open_sync writes", 1);
}
/*
* Test open_sync with different size files
*/
static void
test_open_sync(const char *msg, int writes_size)
{
#ifdef OPEN_SYNC_FLAG
int tmpfile,
ops,
writes;
#endif
printf(LABEL_FORMAT, msg);
fflush(stdout);
#ifdef OPEN_SYNC_FLAG
if ((tmpfile = open(filename, O_RDWR | OPEN_SYNC_FLAG | PG_O_DIRECT, 0)) == -1)
printf(NA_FORMAT, "n/a*\n");
else
{
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
for (writes = 0; writes < 16 / writes_size; writes++)
if (write(tmpfile, buf, writes_size * 1024) !=
writes_size * 1024)
die("write failed");
if (lseek(tmpfile, 0, SEEK_SET) == -1)
die("seek failed");
}
STOP_TIMER;
close(tmpfile);
}
#else
printf(NA_FORMAT, "n/a\n");
#endif
}
static void
test_file_descriptor_sync(void)
{
int tmpfile,
ops;
/*
* 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 on a different\n"
"descriptor.)\n");
/*
* first write, fsync and close, which is the normal behavior without
* multiple descriptors
*/
printf(LABEL_FORMAT, "write, fsync, close");
fflush(stdout);
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
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("could not open output file");
close(tmpfile);
}
STOP_TIMER;
/*
* Now open, write, close, open again and fsync This simulates processes
* fsyncing each other's writes.
*/
printf(LABEL_FORMAT, "write, close, fsync");
fflush(stdout);
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
close(tmpfile);
/* reopen file */
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
if (fsync(tmpfile) != 0)
die("fsync failed");
close(tmpfile);
}
STOP_TIMER;
}
static void
test_non_sync(void)
{
int tmpfile,
ops;
/*
* Test a simple write without fsync
*/
printf("\nNon-sync'ed %dkB writes:\n", XLOG_BLCKSZ_K);
printf(LABEL_FORMAT, "write");
fflush(stdout);
START_TIMER;
for (ops = 0; alarm_triggered == false; ops++)
{
if ((tmpfile = open(filename, O_RDWR, 0)) == -1)
die("could not open output file");
if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
die("write failed");
close(tmpfile);
}
STOP_TIMER;
}
static void
signal_cleanup(int signum)
{
/* Delete the file if it exists. Ignore errors */
if (needs_unlink)
unlink(filename);
/* Finish incomplete line on stdout */
puts("");
exit(signum);
}
#ifdef HAVE_FSYNC_WRITETHROUGH
static int
pg_fsync_writethrough(int fd)
{
#ifdef WIN32
return _commit(fd);
#elif defined(F_FULLFSYNC)
return (fcntl(fd, F_FULLFSYNC, 0) == -1) ? -1 : 0;
#else
errno = ENOSYS;
return -1;
#endif
}
#endif
/*
* print out the writes per second for tests
*/
static void
print_elapse(struct timeval start_t, struct timeval stop_t, int ops)
{
double total_time = (stop_t.tv_sec - start_t.tv_sec) +
(stop_t.tv_usec - start_t.tv_usec) * 0.000001;
double per_second = ops / total_time;
double avg_op_time_us = (total_time / ops) * USECS_SEC;
printf(OPS_FORMAT "\n", per_second, avg_op_time_us);
}
#ifndef WIN32
static void
process_alarm(int sig)
{
alarm_triggered = true;
}
#else
static DWORD WINAPI
process_alarm(LPVOID param)
{
/* WIN32 doesn't support alarm, so we create a thread and sleep here */
Sleep(secs_per_test * 1000);
alarm_triggered = true;
ExitThread(0);
}
#endif
static void
die(const char *str)
{
fprintf(stderr, "%s: %s\n", str, strerror(errno));
exit(1);
}