From ec74369931687885cfb6ce9dac55deefdb410086 Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Sat, 1 Sep 2018 19:46:49 +0300 Subject: [PATCH] Implement "pg_ctl logrotate" command Currently there are two ways to trigger log rotation in logging collector process: call pg_rotate_logfile() SQL-function or send SIGUSR1 signal directly to logging collector process. However, it's nice to have more suitable way for external tools to do that, which wouldn't require SQL connection or knowledge of logging collector pid. This commit implements triggering log rotation by "pg_ctl logrotate" command. Discussion: https://postgr.es/m/20180416.115435.28153375.horiguchi.kyotaro%40lab.ntt.co.jp Author: Kyotaro Horiguchi, Alexander Kuzmenkov, Alexander Korotkov --- doc/src/sgml/maintenance.sgml | 34 ++++++++++- doc/src/sgml/ref/pg_ctl-ref.sgml | 13 +++++ src/backend/postmaster/postmaster.c | 18 ++++-- src/backend/postmaster/syslogger.c | 29 +++++++++- src/bin/pg_ctl/pg_ctl.c | 89 +++++++++++++++++++++++++---- src/bin/pg_ctl/t/004_logrotate.pl | 42 ++++++++++++++ src/include/postmaster/syslogger.h | 3 + src/test/perl/PostgresNode.pm | 21 +++++++ 8 files changed, 230 insertions(+), 19 deletions(-) create mode 100644 src/bin/pg_ctl/t/004_logrotate.pl diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml index 4a68ec3b40..02c512f8bc 100644 --- a/doc/src/sgml/maintenance.sgml +++ b/doc/src/sgml/maintenance.sgml @@ -932,8 +932,8 @@ analyze threshold = analyze base threshold + analyze scale factor * number of tu program if you have one that you are already using with other server software. For example, the rotatelogs tool included in the Apache distribution - can be used with PostgreSQL. To do this, - just pipe the server's + can be used with PostgreSQL. One way to + do this is to pipe the server's stderr output to the desired program. If you start the server with pg_ctl, then stderr @@ -945,6 +945,36 @@ pg_ctl start | rotatelogs /var/log/pgsql_log 86400 + + You can combine these approaches by setting up logrotate + to collect log files produced by PostgreSQL built-in + logging collector. In this case, the logging collector defines the names and + location of the log files, while logrotate + periodically archives these files. When initiating log rotation, + logrotate must ensure that the application + sends further output to the new file. This is commonly done with a + postrotate script that sends a SIGHUP + signal to the application, which then reopens the log file. + In PostgreSQL, you can run pg_ctl + with the logrotate option instead. When the server receives + this command, the server either switches to a new log file or reopens the + existing file, depending on the logging configuration + (see ). + + + + + When using static log file names, the server might fail to reopen the log + file if the max open file limit is reached or a file table overflow occurs. + In this case, log messages are sent to the old log file until a + successful log rotation. If logrotate is + configured to compress the log file and delete it, the server may lose + the messages logged in this timeframe. To avoid this issue, you can + configure the logging collector to dynamically assign log file names + and use a prerotate script to ignore open log files. + + + Another production-grade approach to managing log output is to send it to syslog and let diff --git a/doc/src/sgml/ref/pg_ctl-ref.sgml b/doc/src/sgml/ref/pg_ctl-ref.sgml index 304a64d6a6..e31275a04e 100644 --- a/doc/src/sgml/ref/pg_ctl-ref.sgml +++ b/doc/src/sgml/ref/pg_ctl-ref.sgml @@ -97,6 +97,13 @@ PostgreSQL documentation + + pg_ctl + + datadir + + + pg_ctl @@ -226,6 +233,12 @@ PostgreSQL documentation and begin read-write operations. + + mode rotates the server log file. + For details on how to use this mode with external log rotation tools, see + . + + mode sends a signal to a specified process. This is primarily valuable on Microsoft Windows diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 2215ebbb5a..7fb4296b7a 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -1268,6 +1268,9 @@ PostmasterMain(int argc, char *argv[]) */ RemovePromoteSignalFiles(); + /* Do the same for logrotate signal file */ + RemoveLogrotateSignalFiles(); + /* Remove any outdated file holding the current log filenames. */ if (unlink(LOG_METAINFO_DATAFILE) < 0 && errno != ENOENT) ereport(LOG, @@ -5100,11 +5103,18 @@ sigusr1_handler(SIGNAL_ARGS) signal_child(PgArchPID, SIGUSR1); } - if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE) && - SysLoggerPID != 0) + /* Tell syslogger to rotate logfile if requested */ + if (SysLoggerPID != 0) { - /* Tell syslogger to rotate logfile */ - signal_child(SysLoggerPID, SIGUSR1); + if (CheckLogrotateSignal()) + { + signal_child(SysLoggerPID, SIGUSR1); + RemoveLogrotateSignalFiles(); + } + else if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE)) + { + signal_child(SysLoggerPID, SIGUSR1); + } } if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER) && diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c index 2959d1374e..29bdcec895 100644 --- a/src/backend/postmaster/syslogger.c +++ b/src/backend/postmaster/syslogger.c @@ -57,6 +57,9 @@ */ #define READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE) +/* Log rotation signal file path, relative to $PGDATA */ +#define LOGROTATE_SIGNAL_FILE "logrotate" + /* * GUC parameters. Logging_collector cannot be changed after postmaster @@ -405,7 +408,7 @@ SysLoggerMain(int argc, char *argv[]) { /* * Force rotation when both values are zero. It means the request - * was sent by pg_rotate_logfile. + * was sent by pg_rotate_logfile() or "pg_ctl logrotate". */ if (!time_based_rotation && size_rotation_for == 0) size_rotation_for = LOG_DESTINATION_STDERR | LOG_DESTINATION_CSVLOG; @@ -1506,6 +1509,30 @@ update_metainfo_datafile(void) * -------------------------------- */ +/* + * Check to see if a log rotation request has arrived. Should be + * called by postmaster after receiving SIGUSR1. + */ +bool +CheckLogrotateSignal(void) +{ + struct stat stat_buf; + + if (stat(LOGROTATE_SIGNAL_FILE, &stat_buf) == 0) + return true; + + return false; +} + +/* + * Remove the file signaling a log rotateion request. + */ +void +RemoveLogrotateSignalFiles(void) +{ + unlink(LOGROTATE_SIGNAL_FILE); +} + /* SIGHUP: set flag to reload config file */ static void sigHupHandler(SIGNAL_ARGS) diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c index ed2396aa6c..1d0b056dde 100644 --- a/src/bin/pg_ctl/pg_ctl.c +++ b/src/bin/pg_ctl/pg_ctl.c @@ -61,6 +61,7 @@ typedef enum RELOAD_COMMAND, STATUS_COMMAND, PROMOTE_COMMAND, + LOGROTATE_COMMAND, KILL_COMMAND, REGISTER_COMMAND, UNREGISTER_COMMAND, @@ -100,6 +101,7 @@ static char version_file[MAXPGPATH]; static char pid_file[MAXPGPATH]; static char backup_file[MAXPGPATH]; static char promote_file[MAXPGPATH]; +static char logrotate_file[MAXPGPATH]; #ifdef WIN32 static DWORD pgctl_start_type = SERVICE_AUTO_START; @@ -125,6 +127,7 @@ static void do_restart(void); static void do_reload(void); static void do_status(void); static void do_promote(void); +static void do_logrotate(void); static void do_kill(pgpid_t pid); static void print_msg(const char *msg); static void adjust_data_dir(void); @@ -1171,6 +1174,62 @@ do_promote(void) print_msg(_("server promoting\n")); } +/* + * log rotate + */ + +static void +do_logrotate(void) +{ + FILE *logrotatefile; + pgpid_t pid; + + pid = get_pgpid(false); + + if (pid == 0) /* no pid file */ + { + write_stderr(_("%s: PID file \"%s\" does not exist\n"), progname, pid_file); + write_stderr(_("Is server running?\n")); + exit(1); + } + else if (pid < 0) /* standalone backend, not postmaster */ + { + pid = -pid; + write_stderr(_("%s: cannot rotate log file; " + "single-user server is running (PID: %ld)\n"), + progname, pid); + exit(1); + } + + snprintf(logrotate_file, MAXPGPATH, "%s/logrotate", pg_data); + + if ((logrotatefile = fopen(logrotate_file, "w")) == NULL) + { + write_stderr(_("%s: could not create log rotation signal file \"%s\": %s\n"), + progname, logrotate_file, strerror(errno)); + exit(1); + } + if (fclose(logrotatefile)) + { + write_stderr(_("%s: could not write log rotation signal file \"%s\": %s\n"), + progname, logrotate_file, strerror(errno)); + exit(1); + } + + sig = SIGUSR1; + if (kill((pid_t) pid, sig) != 0) + { + write_stderr(_("%s: could not send log rotation signal (PID: %ld): %s\n"), + progname, pid, strerror(errno)); + if (unlink(logrotate_file) != 0) + write_stderr(_("%s: could not remove log rotation signal file \"%s\": %s\n"), + progname, logrotate_file, strerror(errno)); + exit(1); + } + + print_msg(_("server signaled to rotate log file\n")); +} + /* * utility routines @@ -1912,19 +1971,20 @@ do_help(void) { printf(_("%s is a utility to initialize, start, stop, or control a PostgreSQL server.\n\n"), progname); printf(_("Usage:\n")); - printf(_(" %s init[db] [-D DATADIR] [-s] [-o OPTIONS]\n"), progname); - printf(_(" %s start [-D DATADIR] [-l FILENAME] [-W] [-t SECS] [-s]\n" - " [-o OPTIONS] [-p PATH] [-c]\n"), progname); - printf(_(" %s stop [-D DATADIR] [-m SHUTDOWN-MODE] [-W] [-t SECS] [-s]\n"), progname); - printf(_(" %s restart [-D DATADIR] [-m SHUTDOWN-MODE] [-W] [-t SECS] [-s]\n" - " [-o OPTIONS] [-c]\n"), progname); - printf(_(" %s reload [-D DATADIR] [-s]\n"), progname); - printf(_(" %s status [-D DATADIR]\n"), progname); - printf(_(" %s promote [-D DATADIR] [-W] [-t SECS] [-s]\n"), progname); - printf(_(" %s kill SIGNALNAME PID\n"), progname); + printf(_(" %s init[db] [-D DATADIR] [-s] [-o OPTIONS]\n"), progname); + printf(_(" %s start [-D DATADIR] [-l FILENAME] [-W] [-t SECS] [-s]\n" + " [-o OPTIONS] [-p PATH] [-c]\n"), progname); + printf(_(" %s stop [-D DATADIR] [-m SHUTDOWN-MODE] [-W] [-t SECS] [-s]\n"), progname); + printf(_(" %s restart [-D DATADIR] [-m SHUTDOWN-MODE] [-W] [-t SECS] [-s]\n" + " [-o OPTIONS] [-c]\n"), progname); + printf(_(" %s reload [-D DATADIR] [-s]\n"), progname); + printf(_(" %s status [-D DATADIR]\n"), progname); + printf(_(" %s promote [-D DATADIR] [-W] [-t SECS] [-s]\n"), progname); + printf(_(" %s logrotate [-D DATADIR] [-s]\n"), progname); + printf(_(" %s kill SIGNALNAME PID\n"), progname); #ifdef WIN32 - printf(_(" %s register [-D DATADIR] [-N SERVICENAME] [-U USERNAME] [-P PASSWORD]\n" - " [-S START-TYPE] [-e SOURCE] [-W] [-t SECS] [-s] [-o OPTIONS]\n"), progname); + printf(_(" %s register [-D DATADIR] [-N SERVICENAME] [-U USERNAME] [-P PASSWORD]\n" + " [-S START-TYPE] [-e SOURCE] [-W] [-t SECS] [-s] [-o OPTIONS]\n"), progname); printf(_(" %s unregister [-N SERVICENAME]\n"), progname); #endif @@ -2337,6 +2397,8 @@ main(int argc, char **argv) ctl_command = STATUS_COMMAND; else if (strcmp(argv[optind], "promote") == 0) ctl_command = PROMOTE_COMMAND; + else if (strcmp(argv[optind], "logrotate") == 0) + ctl_command = LOGROTATE_COMMAND; else if (strcmp(argv[optind], "kill") == 0) { if (argc - optind < 3) @@ -2443,6 +2505,9 @@ main(int argc, char **argv) case PROMOTE_COMMAND: do_promote(); break; + case LOGROTATE_COMMAND: + do_logrotate(); + break; case KILL_COMMAND: do_kill(killproc); break; diff --git a/src/bin/pg_ctl/t/004_logrotate.pl b/src/bin/pg_ctl/t/004_logrotate.pl new file mode 100644 index 0000000000..fa5ab74817 --- /dev/null +++ b/src/bin/pg_ctl/t/004_logrotate.pl @@ -0,0 +1,42 @@ +use strict; +use warnings; + +use PostgresNode; +use TestLib; +use Test::More tests => 1; +use Time::HiRes qw(usleep); + +my $tempdir = TestLib::tempdir; + +my $node = get_new_node('primary'); +$node->init(allows_streaming => 1); +$node->append_conf( + 'postgresql.conf', qq( +logging_collector = on +log_directory = 'log' +log_filename = 'postgresql.log' +)); + +$node->start(); + +# Rename log file and rotate log. Then log file should appear again. + +my $logfile = $node->data_dir . '/log/postgresql.log'; +my $old_logfile = $node->data_dir . '/log/postgresql.old'; +rename($logfile, $old_logfile); + +$node->logrotate(); + +# pg_ctl logrotate doesn't wait until rotation request being completed. So +# we have to wait some time until log file appears. +my $attempts = 0; +my $max_attempts = 180 * 10; +while (not -e $logfile and $attempts < $max_attempts) +{ + usleep(100_000); + $attempts++; +} + +ok(-e $logfile, "log file exists"); + +$node->stop(); diff --git a/src/include/postmaster/syslogger.h b/src/include/postmaster/syslogger.h index b35fadc1bd..3fcb26cdb8 100644 --- a/src/include/postmaster/syslogger.h +++ b/src/include/postmaster/syslogger.h @@ -87,6 +87,9 @@ extern void write_syslogger_file(const char *buffer, int count, int dest); extern void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn(); #endif +extern bool CheckLogrotateSignal(void); +extern void RemoveLogrotateSignalFiles(void); + /* * Name of files saving meta-data information about the log * files currently in use by the syslogger diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm index 79fb457075..ae3d8ee10c 100644 --- a/src/test/perl/PostgresNode.pm +++ b/src/test/perl/PostgresNode.pm @@ -804,6 +804,27 @@ sub promote return; } +=pod + +=item $node->logrotate() + +Wrapper for pg_ctl logrotate + +=cut + +sub logrotate +{ + my ($self) = @_; + my $port = $self->port; + my $pgdata = $self->data_dir; + my $logfile = $self->logfile; + my $name = $self->name; + print "### Rotating log in node \"$name\"\n"; + TestLib::system_or_bail('pg_ctl', '-D', $pgdata, '-l', $logfile, + 'logrotate'); + return; +} + # Internal routine to enable streaming replication on a standby node. sub enable_streaming {