From 1f7f5a664d15065aee2a431d1e1a3a3657dbd4f3 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Tue, 13 Sep 2016 13:07:12 +0900 Subject: [PATCH 3/4] Add --no-sync option to pg_basebackup This makes pg_basebackup, and is useful for testing. --- 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 | 20 +++++++++++--------- src/bin/pg_basebackup/receivelog.h | 4 +++- 5 files changed, 49 insertions(+), 19 deletions(-) diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml index 9f1eae1..3f1938a 100644 --- a/doc/src/sgml/ref/pg_basebackup.sgml +++ b/doc/src/sgml/ref/pg_basebackup.sgml @@ -439,6 +439,21 @@ PostgreSQL documentation + + + + + By default, pg_basebackup will wait for all files + to be written safely to disk. This option causes + pg_basebackup 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. + + + + + diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c index 2266e34..e2f1629 100644 --- a/src/bin/pg_basebackup/pg_basebackup.c +++ b/src/bin/pg_basebackup/pg_basebackup.c @@ -67,6 +67,7 @@ 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 */ @@ -326,6 +327,7 @@ usage(void) printf(_(" -c, --checkpoint=fast|spread\n" " set fast or spread checkpointing\n")); printf(_(" -l, --label=LABEL set backup label\n")); + printf(_(" -N, --no-sync do not wait for changes to be written safely to disk\n")); printf(_(" -n, --noclean do not clean up after errors\n")); printf(_(" -P, --progress show progress information\n")); printf(_(" -v, --verbose output verbose messages\n")); @@ -458,6 +460,7 @@ 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; @@ -1197,7 +1200,7 @@ 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); } @@ -1965,14 +1968,17 @@ 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) @@ -1999,6 +2005,7 @@ main(int argc, char **argv) {"compress", required_argument, NULL, 'Z'}, {"label", required_argument, NULL, 'l'}, {"noclean", no_argument, NULL, 'n'}, + {"no-sync", no_argument, NULL, 'N'}, {"dbname", required_argument, NULL, 'd'}, {"host", required_argument, NULL, 'h'}, {"port", required_argument, NULL, 'p'}, @@ -2035,7 +2042,7 @@ 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) @@ -2059,6 +2066,9 @@ main(int argc, char **argv) case 'r': maxrate = parse_max_rate(optarg); break; + case 'N': + do_sync = false; + break; case 'R': writerecoveryconf = true; break; diff --git a/src/bin/pg_basebackup/pg_receivexlog.c b/src/bin/pg_basebackup/pg_receivexlog.c index 7f7ee9d..a58a251 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 0a740ce..0c01bfc 100644 --- a/src/bin/pg_basebackup/receivelog.c +++ b/src/bin/pg_basebackup/receivelog.c @@ -53,7 +53,7 @@ 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]; @@ -71,10 +71,10 @@ 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; @@ -135,9 +135,9 @@ 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; @@ -174,9 +174,9 @@ 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) @@ -259,7 +259,8 @@ 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; } @@ -379,7 +380,8 @@ 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; } diff --git a/src/bin/pg_basebackup/receivelog.h b/src/bin/pg_basebackup/receivelog.h index 554ff8b..7a3bbc5 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 */ -- 2.10.0