Use pg_pwrite() in pg_test_fsync.

For consistency with the PostgreSQL behavior this test program is
intended to simulate, use pwrite() instead of lseek() + write().

Also fix the final "non-sync" test, which was opening and closing the
file for every write.

Discussion: https://postgr.es/m/CA%2BhUKGJjjid2BJsvjMALBTduo1ogdx2SPYaTQL3wAy8y2hc4nw%40mail.gmail.com

diff --git a/src/bin/pg_test_fsync/pg_test_fsync.c b/src/bin/pg_test_fsync/pg_test_fsync.c
index 3eddd983c63ba6c7e761f6cd519e0941dcf9f444..29ee7c7d6f174b8683b66fb14c39b443292eedbc 100644 (file)
--- a/src/bin/pg_test_fsync/pg_test_fsync.c
+++ b/src/bin/pg_test_fsync/pg_test_fsync.c
@@ -290,10 +290,11 @@ test_sync(int writes_per_op)
                for (ops = 0; alarm_triggered == false; ops++)
                {
                        for (writes = 0; writes < writes_per_op; writes++)
-                               if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+                               if (pg_pwrite(tmpfile,
+                                                         buf,
+                                                         XLOG_BLCKSZ,
+                                                         writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
                                        die("write failed");
-                       if (lseek(tmpfile, 0, SEEK_SET) == -1)
-                               die("seek failed");
                }
                STOP_TIMER;
                close(tmpfile);
@@ -315,11 +316,12 @@ test_sync(int writes_per_op)
        for (ops = 0; alarm_triggered == false; ops++)
        {
                for (writes = 0; writes < writes_per_op; writes++)
-                       if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+                       if (pg_pwrite(tmpfile,
+                                                 buf,
+                                                 XLOG_BLCKSZ,
+                                                 writes * XLOG_BLCKSZ) != XLOG_BLCKSZ)
                                die("write failed");
                fdatasync(tmpfile);
-               if (lseek(tmpfile, 0, SEEK_SET) == -1)
-                       die("seek failed");
        }
        STOP_TIMER;
        close(tmpfile);
@@ -339,12 +341,13 @@ test_sync(int writes_per_op)
        for (ops = 0; alarm_triggered == false; ops++)
        {
                for (writes = 0; writes < writes_per_op; writes++)
-                       if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+                       if (pg_pwrite(tmpfile,
+                                                 buf,
+                                                 XLOG_BLCKSZ,
+                                                 writes * 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);
@@ -362,12 +365,13 @@ test_sync(int writes_per_op)
        for (ops = 0; alarm_triggered == false; ops++)
        {
                for (writes = 0; writes < writes_per_op; writes++)
-                       if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+                       if (pg_pwrite(tmpfile,
+                                                 buf,
+                                                 XLOG_BLCKSZ,
+                                                 writes * 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);
@@ -393,8 +397,10 @@ test_sync(int writes_per_op)
                for (ops = 0; alarm_triggered == false; ops++)
                {
                        for (writes = 0; writes < writes_per_op; writes++)
-                               if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
-
+                               if (pg_pwrite(tmpfile,
+                                                         buf,
+                                                         XLOG_BLCKSZ,
+                                                         writes * 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
@@ -402,8 +408,6 @@ test_sync(int writes_per_op)
                                         * size, e.g. XFS.
                                         */
                                        die("write failed");
-                       if (lseek(tmpfile, 0, SEEK_SET) == -1)
-                               die("seek failed");
                }
                STOP_TIMER;
                close(tmpfile);
@@ -457,11 +461,12 @@ test_open_sync(const char *msg, int writes_size)
                for (ops = 0; alarm_triggered == false; ops++)
                {
                        for (writes = 0; writes < 16 / writes_size; writes++)
-                               if (write(tmpfile, buf, writes_size * 1024) !=
+                               if (pg_pwrite(tmpfile,
+                                                         buf,
+                                                         writes_size * 1024,
+                                                         writes * writes_size * 1024) !=
                                        writes_size * 1024)
                                        die("write failed");
-                       if (lseek(tmpfile, 0, SEEK_SET) == -1)
-                               die("seek failed");
                }
                STOP_TIMER;
                close(tmpfile);
@@ -553,16 +558,16 @@ test_non_sync(void)
        printf(LABEL_FORMAT, "write");
        fflush(stdout);
 
+       if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
+               die("could not open output file");
        START_TIMER;
        for (ops = 0; alarm_triggered == false; ops++)
        {
-               if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
-                       die("could not open output file");
-               if (write(tmpfile, buf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+               if (pg_pwrite(tmpfile, buf, XLOG_BLCKSZ, 0) != XLOG_BLCKSZ)
                        die("write failed");
-               close(tmpfile);
        }
        STOP_TIMER;
+       close(tmpfile);
 }
 
 static void