diff options
| -rw-r--r-- | src/bin/pg_basebackup/pg_basebackup.c | 47 | ||||
| -rw-r--r-- | src/bin/pg_basebackup/t/010_pg_basebackup.pl | 34 |
2 files changed, 79 insertions, 2 deletions
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c index 8c77c533e64..c1ed7aeeee1 100644 --- a/src/bin/pg_basebackup/pg_basebackup.c +++ b/src/bin/pg_basebackup/pg_basebackup.c @@ -174,6 +174,8 @@ static int bgpipe[2] = {-1, -1}; /* Handle to child process */ static pid_t bgchild = -1; static bool in_log_streamer = false; +/* Flag to indicate if child process exited unexpectedly */ +static volatile sig_atomic_t bgchild_exited = false; /* End position for xlog streaming, empty string if unknown yet */ static XLogRecPtr xlogendptr; @@ -278,6 +280,18 @@ disconnect_atexit(void) #ifndef WIN32 /* + * If the bgchild exits prematurely and raises a SIGCHLD signal, we can abort + * processing rather than wait until the backup has finished and error out at + * that time. On Windows, we use a background thread which can communicate + * without the need for a signal handler. + */ +static void +sigchld_handler(SIGNAL_ARGS) +{ + bgchild_exited = true; +} + +/* * On windows, our background thread dies along with the process. But on * Unix, if we have started a subprocess, we want to kill it off so it * doesn't remain running trying to stream data. @@ -285,7 +299,7 @@ disconnect_atexit(void) static void kill_bgchild_atexit(void) { - if (bgchild > 0) + if (bgchild > 0 && !bgchild_exited) kill(bgchild, SIGTERM); } #endif @@ -572,17 +586,28 @@ LogStreamerMain(logstreamer_param *param) stream.do_sync); if (!ReceiveXlogStream(param->bgconn, &stream)) - + { /* * Any errors will already have been reported in the function process, * but we need to tell the parent that we didn't shutdown in a nice * way. */ +#ifdef WIN32 + /* + * In order to signal the main thread of an ungraceful exit we + * set the same flag that we use on Unix to signal SIGCHLD. + */ + bgchild_exited = true; +#endif return 1; + } if (!stream.walmethod->finish()) { pg_log_error("could not finish writing WAL files: %m"); +#ifdef WIN32 + bgchild_exited = true; +#endif return 1; } @@ -1134,6 +1159,12 @@ ReceiveCopyData(PGconn *conn, WriteDataCallback callback, exit(1); } + if (bgchild_exited) + { + pg_log_error("background process terminated unexpectedly"); + exit(1); + } + (*callback) (r, copybuf, callback_data); PQfreemem(copybuf); @@ -2882,6 +2913,18 @@ main(int argc, char **argv) } atexit(disconnect_atexit); +#ifndef WIN32 + /* + * Trap SIGCHLD to be able to handle the WAL stream process exiting. There + * is no SIGCHLD on Windows, there we rely on the background thread setting + * the signal variable on unexpected but graceful exit. If the WAL stream + * thread crashes on Windows it will bring down the entire process as it's + * a thread, so there is nothing to catch should that happen. A crash on + * UNIX will be caught by the signal handler. + */ + pqsignal(SIGCHLD, sigchld_handler); +#endif + /* * Set umask so that directories/files are created with the same * permissions as directories/files in the source data directory. diff --git a/src/bin/pg_basebackup/t/010_pg_basebackup.pl b/src/bin/pg_basebackup/t/010_pg_basebackup.pl index 75d6810d3e6..8cb8cfe045e 100644 --- a/src/bin/pg_basebackup/t/010_pg_basebackup.pl +++ b/src/bin/pg_basebackup/t/010_pg_basebackup.pl @@ -776,4 +776,38 @@ SKIP: rmtree("$tempdir/backup_gzip3"); } +# Test background stream process terminating before the basebackup has +# finished, the main process should exit gracefully with an error message on +# stderr. To reduce the risk of timing related issues we invoke the base +# backup with rate throttling enabled. +$node->safe_psql('postgres', + q{CREATE TABLE t AS SELECT a FROM generate_series(1,10000) AS a;}); + +my $sigchld_bb_timeout = IPC::Run::timer(60); +my ($sigchld_bb_stdin, $sigchld_bb_stdout, $sigchld_bb_stderr) = ('', '', ''); +my $sigchld_bb = IPC::Run::start( + [ + @pg_basebackup_defs, '--wal-method=stream', '-D', "$tempdir/sigchld", + '--max-rate=32', '-d', $node->connstr('postgres') + ], + '<', + \$sigchld_bb_stdin, + '>', + \$sigchld_bb_stdout, + '2>', + \$sigchld_bb_stderr, + $sigchld_bb_timeout); + +is($node->poll_query_until('postgres', + "SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE " . + "application_name = '010_pg_basebackup.pl' AND wait_event = 'WalSenderMain' " . + "AND backend_type = 'walsender' AND query ~ 'START_REPLICATION'"), + "1", + "Walsender killed"); + +ok(pump_until($sigchld_bb, $sigchld_bb_timeout, \$sigchld_bb_stderr, + qr/background process terminated unexpectedly/), + 'background process exit message'); +$sigchld_bb->finish(); + done_testing(); |