From 6ed2d8584cc680a2d6898480de74a57cd96176b5 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Thu, 29 Sep 2016 12:00:00 -0400
Subject: [PATCH] pg_basebackup: Add --nosync option
This is useful for testing, similar to initdb's --nosync.
From: Michael Paquier <michael.paquier@gmail.com>
---
doc/src/sgml/ref/pg_basebackup.sgml | 15 ++++++++++++
src/bin/pg_basebackup/pg_basebackup.c | 28 ++++++++++++++-------
src/bin/pg_basebackup/pg_receivexlog.c | 1 +
src/bin/pg_basebackup/receivelog.c | 34 ++++++++++++++------------
src/bin/pg_basebackup/receivelog.h | 4 ++-
5 files changed, 56 insertions(+), 26 deletions(-)
diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml
index fe557ed002f..55e913f70de 100644
--- a/doc/src/sgml/ref/pg_basebackup.sgml
+++ b/doc/src/sgml/ref/pg_basebackup.sgml
@@ -438,6 +438,21 @@ PostgreSQL documentation
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>-N</option></term>
+ <term><option>--nosync</option></term>
+ <listitem>
+ <para>
+ By default, <command>pg_basebackup</command> will wait for all files
+ to be written safely to disk. This option causes
+ <command>pg_basebackup</command> to return without waiting, which is
+ faster, but means that a subsequent operating system crash can leave
+ the base backup corrupt. Generally, this option is useful for testing
+ but should not be used when creating a production installation.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>-v</option></term>
<term><option>--verbose</option></term>
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index cd7d095103d..0f5d9d6a87f 100644
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -69,6 +69,7 @@ static bool includewal = false;
static bool streamwal = false;
static bool fastcheckpoint = false;
static bool writerecoveryconf = false;
+static bool do_sync = true;
static int standby_message_timeout = 10 * 1000; /* 10 sec = default */
static pg_time_t last_progress_report = 0;
static int32 maxrate = 0; /* no limit by default */
@@ -329,6 +330,7 @@ usage(void)
" set fast or spread checkpointing\n"));
printf(_(" -l, --label=LABEL set backup label\n"));
printf(_(" -n, --noclean do not clean up after errors\n"));
+ printf(_(" -N, --nosync do not wait for changes to be written safely to disk\n"));
printf(_(" -P, --progress show progress information\n"));
printf(_(" -v, --verbose output verbose messages\n"));
printf(_(" -V, --version output version information, then exit\n"));
@@ -460,6 +462,7 @@ LogStreamerMain(logstreamer_param *param)
stream.stream_stop = reached_end_position;
stream.standby_message_timeout = standby_message_timeout;
stream.synchronous = false;
+ stream.do_sync = do_sync;
stream.mark_done = true;
stream.basedir = param->xlogdir;
stream.partial_suffix = NULL;
@@ -1199,7 +1202,7 @@ ReceiveTarFile(PGconn *conn, PGresult *res, int rownum)
PQfreemem(copybuf);
/* sync the resulting tar file, errors are not considered fatal */
- if (strcmp(basedir, "-") != 0)
+ if (do_sync && strcmp(basedir, "-") != 0)
(void) fsync_fname(filename, false, progname);
}
@@ -1967,14 +1970,17 @@ BaseBackup(void)
* all the data of the base directory is synced, taking into account
* all the tablespaces. Errors are not considered fatal.
*/
- if (format == 't')
+ if (do_sync)
{
- if (strcmp(basedir, "-") != 0)
- (void) fsync_fname(basedir, true, progname);
- }
- else
- {
- (void) fsync_pgdata(basedir, progname);
+ if (format == 't')
+ {
+ if (strcmp(basedir, "-") != 0)
+ (void) fsync_fname(basedir, true, progname);
+ }
+ else
+ {
+ (void) fsync_pgdata(basedir, progname);
+ }
}
if (verbose)
@@ -2001,6 +2007,7 @@ main(int argc, char **argv)
{"compress", required_argument, NULL, 'Z'},
{"label", required_argument, NULL, 'l'},
{"noclean", no_argument, NULL, 'n'},
+ {"nosync", no_argument, NULL, 'N'},
{"dbname", required_argument, NULL, 'd'},
{"host", required_argument, NULL, 'h'},
{"port", required_argument, NULL, 'p'},
@@ -2037,7 +2044,7 @@ main(int argc, char **argv)
atexit(cleanup_directories_atexit);
- while ((c = getopt_long(argc, argv, "D:F:r:RT:xX:l:nzZ:d:c:h:p:U:s:S:wWvP",
+ while ((c = getopt_long(argc, argv, "D:F:r:RT:xX:l:nNzZ:d:c:h:p:U:s:S:wWvP",
long_options, &option_index)) != -1)
{
switch (c)
@@ -2115,6 +2122,9 @@ main(int argc, char **argv)
case 'n':
noclean = true;
break;
+ case 'N':
+ do_sync = false;
+ break;
case 'z':
#ifdef HAVE_LIBZ
compresslevel = Z_DEFAULT_COMPRESSION;
diff --git a/src/bin/pg_basebackup/pg_receivexlog.c b/src/bin/pg_basebackup/pg_receivexlog.c
index 7f7ee9dc9ba..a58a251a59f 100644
--- a/src/bin/pg_basebackup/pg_receivexlog.c
+++ b/src/bin/pg_basebackup/pg_receivexlog.c
@@ -336,6 +336,7 @@ StreamLog(void)
stream.stream_stop = stop_streaming;
stream.standby_message_timeout = standby_message_timeout;
stream.synchronous = synchronous;
+ stream.do_sync = true;
stream.mark_done = false;
stream.basedir = basedir;
stream.partial_suffix = ".partial";
diff --git a/src/bin/pg_basebackup/receivelog.c b/src/bin/pg_basebackup/receivelog.c
index 6b78a60f278..8f29d191144 100644
--- a/src/bin/pg_basebackup/receivelog.c
+++ b/src/bin/pg_basebackup/receivelog.c
@@ -41,8 +41,8 @@ static PGresult *HandleCopyStream(PGconn *conn, StreamCtl *stream,
XLogRecPtr *stoppos);
static int CopyStreamPoll(PGconn *conn, long timeout_ms);
static int CopyStreamReceive(PGconn *conn, long timeout, char **buffer);
-static bool ProcessKeepaliveMsg(PGconn *conn, char *copybuf, int len,
- XLogRecPtr blockpos, int64 *last_status);
+static bool ProcessKeepaliveMsg(PGconn *conn, StreamCtl *stream, char *copybuf,
+ int len, XLogRecPtr blockpos, int64 *last_status);
static bool ProcessXLogDataMsg(PGconn *conn, StreamCtl *stream, char *copybuf, int len,
XLogRecPtr *blockpos);
static PGresult *HandleEndOfCopyStream(PGconn *conn, StreamCtl *stream, char *copybuf,
@@ -56,7 +56,7 @@ static bool ReadEndOfStreamingResult(PGresult *res, XLogRecPtr *startpos,
uint32 *timeline);
static bool
-mark_file_as_archived(const char *basedir, const char *fname)
+mark_file_as_archived(const char *basedir, const char *fname, bool do_sync)
{
int fd;
static char tmppath[MAXPGPATH];
@@ -74,10 +74,10 @@ mark_file_as_archived(const char *basedir, const char *fname)
close(fd);
- if (fsync_fname(tmppath, false, progname) != 0)
+ if (do_sync && fsync_fname(tmppath, false, progname) != 0)
return false;
- if (fsync_parent_path(tmppath, progname) != 0)
+ if (do_sync && fsync_parent_path(tmppath, progname) != 0)
return false;
return true;
@@ -134,9 +134,9 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
* fsync, in case of a previous crash between padding and fsyncing the
* file.
*/
- if (fsync_fname(fn, false, progname) != 0)
+ if (stream->do_sync && fsync_fname(fn, false, progname) != 0)
return false;
- if (fsync_parent_path(fn, progname) != 0)
+ if (stream->do_sync && fsync_parent_path(fn, progname) != 0)
return false;
return true;
@@ -173,9 +173,9 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
* using synchronous mode, where the file is modified and fsynced
* in-place, without a directory fsync.
*/
- if (fsync_fname(fn, false, progname) != 0)
+ if (stream->do_sync && fsync_fname(fn, false, progname) != 0)
return false;
- if (fsync_parent_path(fn, progname) != 0)
+ if (stream->do_sync && fsync_parent_path(fn, progname) != 0)
return false;
if (lseek(f, SEEK_SET, 0) != 0)
@@ -212,7 +212,7 @@ close_walfile(StreamCtl *stream, XLogRecPtr pos)
return false;
}
- if (fsync(walfile) != 0)
+ if (stream->do_sync && fsync(walfile) != 0)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
@@ -258,7 +258,8 @@ close_walfile(StreamCtl *stream, XLogRecPtr pos)
if (currpos == XLOG_SEG_SIZE && stream->mark_done)
{
/* writes error message if failed */
- if (!mark_file_as_archived(stream->basedir, current_walfile_name))
+ if (!mark_file_as_archived(stream->basedir, current_walfile_name,
+ stream->do_sync))
return false;
}
@@ -378,7 +379,8 @@ writeTimeLineHistoryFile(StreamCtl *stream, char *filename, char *content)
if (stream->mark_done)
{
/* writes error message if failed */
- if (!mark_file_as_archived(stream->basedir, histfname))
+ if (!mark_file_as_archived(stream->basedir, histfname,
+ stream->do_sync))
return false;
}
@@ -836,7 +838,7 @@ HandleCopyStream(PGconn *conn, StreamCtl *stream,
*/
if (stream->synchronous && lastFlushPosition < blockpos && walfile != -1)
{
- if (fsync(walfile) != 0)
+ if (stream->do_sync && fsync(walfile) != 0)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
@@ -890,7 +892,7 @@ HandleCopyStream(PGconn *conn, StreamCtl *stream,
/* Check the message type. */
if (copybuf[0] == 'k')
{
- if (!ProcessKeepaliveMsg(conn, copybuf, r, blockpos,
+ if (!ProcessKeepaliveMsg(conn, stream, copybuf, r, blockpos,
&last_status))
goto error;
}
@@ -1043,7 +1045,7 @@ CopyStreamReceive(PGconn *conn, long timeout, char **buffer)
* Process the keepalive message.
*/
static bool
-ProcessKeepaliveMsg(PGconn *conn, char *copybuf, int len,
+ProcessKeepaliveMsg(PGconn *conn, StreamCtl *stream, char *copybuf, int len,
XLogRecPtr blockpos, int64 *last_status)
{
int pos;
@@ -1079,7 +1081,7 @@ ProcessKeepaliveMsg(PGconn *conn, char *copybuf, int len,
* data has been successfully replicated or not, at the normal
* shutdown of the server.
*/
- if (fsync(walfile) != 0)
+ if (stream->do_sync && fsync(walfile) != 0)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
diff --git a/src/bin/pg_basebackup/receivelog.h b/src/bin/pg_basebackup/receivelog.h
index 554ff8b5b28..7a3bbc50800 100644
--- a/src/bin/pg_basebackup/receivelog.h
+++ b/src/bin/pg_basebackup/receivelog.h
@@ -34,8 +34,10 @@ typedef struct StreamCtl
* timeline */
int standby_message_timeout; /* Send status messages this
* often */
- bool synchronous; /* Flush data on write */
+ bool synchronous; /* Flush immediately WAL data on write */
bool mark_done; /* Mark segment as done in generated archive */
+ bool do_sync; /* Flush to disk to ensure consistent state
+ * of data */
stream_stop_callback stream_stop; /* Stop streaming when returns true */
--
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