From aad88158d889e92a5c46bf47e94e87f7b6a09a36 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Thu, 19 Mar 2020 13:40:17 +1300 Subject: [PATCH v25 3/5] Make archiver process an auxiliary process. Author: Kyotaro Horiguchi Discussion: https://postgre.es/m/20180629.173418.190173462.horiguchi.kyotaro%40lab.ntt.co.jp --- src/backend/bootstrap/bootstrap.c | 8 +++ src/backend/postmaster/pgarch.c | 98 +++++++---------------------- src/backend/postmaster/postmaster.c | 43 ++++++++----- src/backend/utils/init/miscinit.c | 6 +- src/include/miscadmin.h | 2 + src/include/postmaster/pgarch.h | 4 +- 6 files changed, 66 insertions(+), 95 deletions(-) diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c index 5480a024e0..423bf99958 100644 --- a/src/backend/bootstrap/bootstrap.c +++ b/src/backend/bootstrap/bootstrap.c @@ -319,6 +319,9 @@ AuxiliaryProcessMain(int argc, char *argv[]) case StartupProcess: MyBackendType = B_STARTUP; break; + case ArchiverProcess: + MyBackendType = B_ARCHIVER; + break; case BgWriterProcess: MyBackendType = B_BG_WRITER; break; @@ -443,6 +446,11 @@ AuxiliaryProcessMain(int argc, char *argv[]) StartupProcessMain(); proc_exit(1); /* should never return */ + case ArchiverProcess: + /* don't set signals, archiver has its own agenda */ + PgArchiverMain(); + proc_exit(1); /* should never return */ + case BgWriterProcess: /* don't set signals, bgwriter has its own agenda */ BackgroundWriterMain(); diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c index 01ffd6513c..589637c2de 100644 --- a/src/backend/postmaster/pgarch.c +++ b/src/backend/postmaster/pgarch.c @@ -78,7 +78,6 @@ * Local data * ---------- */ -static time_t last_pgarch_start_time; static time_t last_sigterm_time = 0; /* @@ -95,7 +94,6 @@ static volatile sig_atomic_t ready_to_stop = false; static pid_t pgarch_forkexec(void); #endif -NON_EXEC_STATIC void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn(); static void pgarch_exit(SIGNAL_ARGS); static void pgarch_waken(SIGNAL_ARGS); static void pgarch_waken_stop(SIGNAL_ARGS); @@ -111,75 +109,6 @@ static void pgarch_archiveDone(char *xlog); * ------------------------------------------------------------ */ -/* - * pgarch_start - * - * Called from postmaster at startup or after an existing archiver - * died. Attempt to fire up a fresh archiver process. - * - * Returns PID of child process, or 0 if fail. - * - * Note: if fail, we will be called again from the postmaster main loop. - */ -int -pgarch_start(void) -{ - time_t curtime; - pid_t pgArchPid; - - /* - * Do nothing if no archiver needed - */ - if (!XLogArchivingActive()) - return 0; - - /* - * Do nothing if too soon since last archiver start. This is a safety - * valve to protect against continuous respawn attempts if the archiver is - * dying immediately at launch. Note that since we will be re-called from - * the postmaster main loop, we will get another chance later. - */ - curtime = time(NULL); - if ((unsigned int) (curtime - last_pgarch_start_time) < - (unsigned int) PGARCH_RESTART_INTERVAL) - return 0; - last_pgarch_start_time = curtime; - -#ifdef EXEC_BACKEND - switch ((pgArchPid = pgarch_forkexec())) -#else - switch ((pgArchPid = fork_process())) -#endif - { - case -1: - ereport(LOG, - (errmsg("could not fork archiver: %m"))); - return 0; - -#ifndef EXEC_BACKEND - case 0: - /* in postmaster child ... */ - InitPostmasterChild(); - - /* Close the postmaster's sockets */ - ClosePostmasterPorts(false); - - /* Drop our connection to postmaster's shared memory, as well */ - dsm_detach_all(); - PGSharedMemoryDetach(); - - PgArchiverMain(0, NULL); - break; -#endif - - default: - return (int) pgArchPid; - } - - /* shouldn't get here */ - return 0; -} - /* ------------------------------------------------------------ * Local functions called by archiver follow * ------------------------------------------------------------ @@ -219,8 +148,8 @@ pgarch_forkexec(void) * The argc/argv parameters are valid only in EXEC_BACKEND case. However, * since we don't use 'em, it hardly matters... */ -NON_EXEC_STATIC void -PgArchiverMain(int argc, char *argv[]) +void +PgArchiverMain(void) { /* * Ignore all signals usually bound to some action in the postmaster, @@ -250,8 +179,27 @@ PgArchiverMain(int argc, char *argv[]) static void pgarch_exit(SIGNAL_ARGS) { - /* SIGQUIT means curl up and die ... */ - exit(1); + PG_SETMASK(&BlockSig); + + /* + * We DO NOT want to run proc_exit() callbacks -- we're here because + * shared memory may be corrupted, so we don't want to try to clean up our + * transaction. Just nail the windows shut and get out of town. Now that + * there's an atexit callback to prevent third-party code from breaking + * things by calling exit() directly, we have to reset the callbacks + * explicitly to make this work as intended. + */ + on_exit_reset(); + + /* + * Note we do exit(2) not exit(0). This is to force the postmaster into a + * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random + * process. This is necessary precisely because we don't clean up our + * shared memory state. (The "dead man switch" mechanism in pmsignal.c + * should ensure the postmaster sees this as a crash, too, but no harm in + * being doubly sure.) + */ + exit(2); } /* SIGUSR1 signal handler for archiver process */ diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 2b9ab32293..cab7fb5381 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -146,7 +146,8 @@ #define BACKEND_TYPE_AUTOVAC 0x0002 /* autovacuum worker process */ #define BACKEND_TYPE_WALSND 0x0004 /* walsender process */ #define BACKEND_TYPE_BGWORKER 0x0008 /* bgworker process */ -#define BACKEND_TYPE_ALL 0x000F /* OR of all the above */ +#define BACKEND_TYPE_ARCHIVER 0x0010 /* archiver process */ +#define BACKEND_TYPE_ALL 0x001F /* OR of all the above */ #define BACKEND_TYPE_WORKER (BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER) @@ -539,6 +540,7 @@ static void ShmemBackendArrayRemove(Backend *bn); #endif /* EXEC_BACKEND */ #define StartupDataBase() StartChildProcess(StartupProcess) +#define StartArchiver() StartChildProcess(ArchiverProcess) #define StartBackgroundWriter() StartChildProcess(BgWriterProcess) #define StartCheckpointer() StartChildProcess(CheckpointerProcess) #define StartWalWriter() StartChildProcess(WalWriterProcess) @@ -1785,7 +1787,7 @@ ServerLoop(void) /* If we have lost the archiver, try to start a new one. */ if (PgArchPID == 0 && PgArchStartupAllowed()) - PgArchPID = pgarch_start(); + PgArchPID = StartArchiver(); /* If we need to signal the autovacuum launcher, do so now */ if (avlauncher_needs_signal) @@ -3055,7 +3057,7 @@ reaper(SIGNAL_ARGS) if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0) AutoVacPID = StartAutoVacLauncher(); if (PgArchStartupAllowed() && PgArchPID == 0) - PgArchPID = pgarch_start(); + PgArchPID = StartArchiver(); if (PgStatPID == 0) PgStatPID = pgstat_start(); @@ -3190,20 +3192,16 @@ reaper(SIGNAL_ARGS) } /* - * Was it the archiver? If so, just try to start a new one; no need - * to force reset of the rest of the system. (If fail, we'll try - * again in future cycles of the main loop.). Unless we were waiting - * for it to shut down; don't restart it in that case, and - * PostmasterStateMachine() will advance to the next shutdown step. + * Was it the archiver? Normal exit can be ignored; we'll start a new + * one at the next iteration of the postmaster's main loop, if + * necessary. Any other exit condition is treated as a crash. */ if (pid == PgArchPID) { PgArchPID = 0; if (!EXIT_STATUS_0(exitstatus)) - LogChildExit(LOG, _("archiver process"), - pid, exitstatus); - if (PgArchStartupAllowed()) - PgArchPID = pgarch_start(); + HandleChildCrash(pid, exitstatus, + _("archiver process")); continue; } @@ -3451,7 +3449,7 @@ CleanupBackend(int pid, /* * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer, - * walwriter, autovacuum, or background worker. + * walwriter, autovacuum, archiver or background worker. * * The objectives here are to clean up our local state about the child * process, and to signal all other remaining children to quickdie. @@ -3656,6 +3654,18 @@ HandleChildCrash(int pid, int exitstatus, const char *procname) signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT)); } + /* Take care of the archiver too */ + if (pid == PgArchPID) + PgArchPID = 0; + else if (PgArchPID != 0 && take_action) + { + ereport(DEBUG2, + (errmsg_internal("sending %s to process %d", + (SendStop ? "SIGSTOP" : "SIGQUIT"), + (int) PgArchPID))); + signal_child(PgArchPID, (SendStop ? SIGSTOP : SIGQUIT)); + } + /* * Force a power-cycle of the pgarch process too. (This isn't absolutely * necessary, but it seems like a good idea for robustness, and it @@ -3928,6 +3938,7 @@ PostmasterStateMachine(void) Assert(CheckpointerPID == 0); Assert(WalWriterPID == 0); Assert(AutoVacPID == 0); + Assert(PgArchPID == 0); /* syslogger is not considered here */ pmState = PM_NO_CHILDREN; } @@ -5208,7 +5219,7 @@ sigusr1_handler(SIGNAL_ARGS) */ Assert(PgArchPID == 0); if (XLogArchivingAlways()) - PgArchPID = pgarch_start(); + PgArchPID = StartArchiver(); /* * If we aren't planning to enter hot standby mode later, treat @@ -5493,6 +5504,10 @@ StartChildProcess(AuxProcType type) ereport(LOG, (errmsg("could not fork startup process: %m"))); break; + case ArchiverProcess: + ereport(LOG, + (errmsg("could not fork archiver process: %m"))); + break; case BgWriterProcess: ereport(LOG, (errmsg("could not fork background writer process: %m"))); diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index a7b7b12249..1d1ebd6a23 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -199,6 +199,9 @@ GetBackendTypeDesc(BackendType backendType) case B_INVALID: backendDesc = "not initialized"; break; + case B_ARCHIVER: + backendDesc = "archiver"; + break; case B_AUTOVAC_LAUNCHER: backendDesc = "autovacuum launcher"; break; @@ -229,9 +232,6 @@ GetBackendTypeDesc(BackendType backendType) case B_WAL_WRITER: backendDesc = "walwriter"; break; - case B_ARCHIVER: - backendDesc = "archiver"; - break; case B_STATS_COLLECTOR: backendDesc = "stats collector"; break; diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index 14fa127ab1..619b2f9c71 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -417,6 +417,7 @@ typedef enum BootstrapProcess, StartupProcess, BgWriterProcess, + ArchiverProcess, CheckpointerProcess, WalWriterProcess, WalReceiverProcess, @@ -429,6 +430,7 @@ extern AuxProcType MyAuxProcType; #define AmBootstrapProcess() (MyAuxProcType == BootstrapProcess) #define AmStartupProcess() (MyAuxProcType == StartupProcess) #define AmBackgroundWriterProcess() (MyAuxProcType == BgWriterProcess) +#define AmArchiverProcess() (MyAuxProcType == ArchiverProcess) #define AmCheckpointerProcess() (MyAuxProcType == CheckpointerProcess) #define AmWalWriterProcess() (MyAuxProcType == WalWriterProcess) #define AmWalReceiverProcess() (MyAuxProcType == WalReceiverProcess) diff --git a/src/include/postmaster/pgarch.h b/src/include/postmaster/pgarch.h index b3200874ca..e3ffc63f14 100644 --- a/src/include/postmaster/pgarch.h +++ b/src/include/postmaster/pgarch.h @@ -32,8 +32,6 @@ */ extern int pgarch_start(void); -#ifdef EXEC_BACKEND -extern void PgArchiverMain(int argc, char *argv[]) pg_attribute_noreturn(); -#endif +extern void PgArchiverMain(void) pg_attribute_noreturn(); #endif /* _PGARCH_H */ -- 2.20.1