diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml index 4a68ec3..b028246 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 @@ -946,6 +946,34 @@ pg_ctl start | rotatelogs /var/log/pgsql_log 86400 + A combined approach is also possible, where logrotate + collects log files produced by the built-in logging collector of + PostgreSQL. In this setup, the location and names of + the log files are determined by logging collector, and + logrotate periodically archives these files. There + must be some way for logrotate to inform the + application that the log file it is using is going to be archived, and that it + must direct further output to a 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, the same effect is achieved with the + logrotate command of pg_ctl. When + the server receives this command, it switches to the new log files according to + its configuration (see ). If the + server is configured to use a static log file name, it just reopens the file. + Note that a setup with a static log file name might lose some log + messages on busy systems, where the server might temporarily fail to reopen + the log file due to max open file limit or file table overflow. When the server + encounters these errors, it continues to use the old log file. Given this behavior, + if logrotate is configured, for example, to compress + the log file and delete it, the server might continue using the already + unlinked file, and the messages logged until the next successful rotation will + be lost. One way to avoid this problem is to configure the logging collector to + use a dynamic log file name, 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 syslog deal with file rotation. To do this, set the @@ -958,7 +986,6 @@ pg_ctl start | rotatelogs /var/log/pgsql_log 86400 configured to work with log files from syslog. - On many systems, however, syslog is not very reliable, particularly with large log messages; it might truncate or drop messages diff --git a/doc/src/sgml/ref/pg_ctl-ref.sgml b/doc/src/sgml/ref/pg_ctl-ref.sgml index 0816bc1..acd1d91 100644 --- a/doc/src/sgml/ref/pg_ctl-ref.sgml +++ b/doc/src/sgml/ref/pg_ctl-ref.sgml @@ -102,6 +102,12 @@ PostgreSQL documentation signal_name process_id + + + + pg_ctl + + datadir On Microsoft Windows, also: @@ -234,6 +240,12 @@ PostgreSQL documentation + mode commands the server to rotate its log file. + For the discussion of how to use this with external log rotation tools, see + . + + + mode registers the PostgreSQL server as a system service on Microsoft Windows. The option allows selection of service start type, diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index d948369..4549f2e 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -385,6 +385,9 @@ static bool LoadedSSL = false; static DNSServiceRef bonjour_sdref = NULL; #endif +/* Log rotation signal file path, relative to $PGDATA */ +#define LOGROTATE_SIGNAL_FILE "logrotate" + /* * postmaster.c - function prototypes */ @@ -398,6 +401,7 @@ static void reset_shared(int port); static void SIGHUP_handler(SIGNAL_ARGS); static void pmdie(SIGNAL_ARGS); static void reaper(SIGNAL_ARGS); +static bool checkLogrotateSignal(void); static void sigusr1_handler(SIGNAL_ARGS); static void startup_die(SIGNAL_ARGS); static void dummy_handler(SIGNAL_ARGS); @@ -4995,6 +4999,24 @@ ExitPostmaster(int status) } /* + * Check to see if a log rotation request has arrived. Should be + * called by postmaster after receiving SIGUSR1. + */ +static bool +checkLogrotateSignal(void) +{ + struct stat stat_buf; + + if (stat(LOGROTATE_SIGNAL_FILE, &stat_buf) == 0) + { + unlink(LOGROTATE_SIGNAL_FILE); + return true; + } + + return false; +} + +/* * sigusr1_handler - handle signal conditions from child processes */ static void @@ -5092,7 +5114,8 @@ sigusr1_handler(SIGNAL_ARGS) signal_child(PgArchPID, SIGUSR1); } - if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE) && + if ((checkLogrotateSignal() || + CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE)) && SysLoggerPID != 0) { /* Tell syslogger to rotate logfile */ diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c index 58b759f..41f036f 100644 --- a/src/backend/postmaster/syslogger.c +++ b/src/backend/postmaster/syslogger.c @@ -388,7 +388,7 @@ 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; diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c index 143021d..5abafb2 100644 --- a/src/bin/pg_ctl/pg_ctl.c +++ b/src/bin/pg_ctl/pg_ctl.c @@ -59,6 +59,7 @@ typedef enum STOP_COMMAND, RESTART_COMMAND, RELOAD_COMMAND, + LOGROTATE_COMMAND, STATUS_COMMAND, PROMOTE_COMMAND, KILL_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(_("commanded to rotate log file\n")); +} + /* * utility routines @@ -2332,6 +2391,8 @@ main(int argc, char **argv) ctl_command = RESTART_COMMAND; else if (strcmp(argv[optind], "reload") == 0) ctl_command = RELOAD_COMMAND; + else if (strcmp(argv[optind], "logrotate") == 0) + ctl_command = LOGROTATE_COMMAND; else if (strcmp(argv[optind], "status") == 0) ctl_command = STATUS_COMMAND; else if (strcmp(argv[optind], "promote") == 0) @@ -2442,6 +2503,9 @@ main(int argc, char **argv) case PROMOTE_COMMAND: do_promote(); break; + case LOGROTATE_COMMAND: + do_logrotate(); + break; case KILL_COMMAND: do_kill(killproc); break;