mirror of https://github.com/postgres/postgres
Startup process now has its own dedicated file, just like all other special/background processes. Reduces role and size of xlog.cpull/1/head
Simon Riggs
14 years ago
parent
86e3364899
commit
9aceb6ab3c
@ -0,0 +1,259 @@ |
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/*-------------------------------------------------------------------------
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* |
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* startup.c |
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* |
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* The Startup process initialises the server and performs any recovery |
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* actions that have been specified. Notice that there is no "main loop" |
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* since the Startup process ends as soon as initialisation is complete. |
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* |
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* |
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* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group |
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* |
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* |
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* IDENTIFICATION |
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* src/backend/postmaster/startup.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#include "postgres.h" |
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#include <signal.h> |
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#include <unistd.h> |
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#include "access/xlog.h" |
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#include "libpq/pqsignal.h" |
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#include "miscadmin.h" |
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#include "postmaster/startup.h" |
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#include "storage/ipc.h" |
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#include "storage/latch.h" |
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#include "storage/pmsignal.h" |
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#include "storage/proc.h" |
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#include "utils/guc.h" |
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/*
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* Flags set by interrupt handlers for later service in the redo loop. |
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*/ |
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static volatile sig_atomic_t got_SIGHUP = false; |
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static volatile sig_atomic_t shutdown_requested = false; |
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static volatile sig_atomic_t promote_triggered = false; |
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/*
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* Flag set when executing a restore command, to tell SIGTERM signal handler |
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* that it's safe to just proc_exit. |
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*/ |
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static volatile sig_atomic_t in_restore_command = false; |
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/* Signal handlers */ |
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static void startupproc_quickdie(SIGNAL_ARGS); |
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static void StartupProcSigUsr1Handler(SIGNAL_ARGS); |
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static void StartupProcTriggerHandler(SIGNAL_ARGS); |
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static void StartupProcSigHupHandler(SIGNAL_ARGS); |
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/* --------------------------------
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* signal handler routines |
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* -------------------------------- |
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*/ |
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/*
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* startupproc_quickdie() occurs when signalled SIGQUIT by the postmaster. |
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* |
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* Some backend has bought the farm, |
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* so we need to stop what we're doing and exit. |
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*/ |
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static void |
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startupproc_quickdie(SIGNAL_ARGS) |
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{ |
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PG_SETMASK(&BlockSig); |
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/*
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* We DO NOT want to run proc_exit() callbacks -- we're here because |
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* shared memory may be corrupted, so we don't want to try to clean up our |
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* transaction. Just nail the windows shut and get out of town. Now that |
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* there's an atexit callback to prevent third-party code from breaking |
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* things by calling exit() directly, we have to reset the callbacks |
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* explicitly to make this work as intended. |
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*/ |
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on_exit_reset(); |
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/*
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* Note we do exit(2) not exit(0). This is to force the postmaster into a |
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* system reset cycle if some idiot DBA sends a manual SIGQUIT to a random |
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* backend. This is necessary precisely because we don't clean up our |
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* shared memory state. (The "dead man switch" mechanism in pmsignal.c |
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* should ensure the postmaster sees this as a crash, too, but no harm in |
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* being doubly sure.) |
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*/ |
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exit(2); |
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} |
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/* SIGUSR1: let latch facility handle the signal */ |
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static void |
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StartupProcSigUsr1Handler(SIGNAL_ARGS) |
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{ |
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int save_errno = errno; |
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latch_sigusr1_handler(); |
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errno = save_errno; |
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} |
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/* SIGUSR2: set flag to finish recovery */ |
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static void |
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StartupProcTriggerHandler(SIGNAL_ARGS) |
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{ |
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int save_errno = errno; |
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promote_triggered = true; |
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WakeupRecovery(); |
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errno = save_errno; |
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} |
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/* SIGHUP: set flag to re-read config file at next convenient time */ |
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static void |
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StartupProcSigHupHandler(SIGNAL_ARGS) |
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{ |
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int save_errno = errno; |
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got_SIGHUP = true; |
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WakeupRecovery(); |
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errno = save_errno; |
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} |
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/* SIGTERM: set flag to abort redo and exit */ |
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static void |
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StartupProcShutdownHandler(SIGNAL_ARGS) |
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{ |
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int save_errno = errno; |
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if (in_restore_command) |
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proc_exit(1); |
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else |
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shutdown_requested = true; |
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WakeupRecovery(); |
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errno = save_errno; |
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} |
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/* Handle SIGHUP and SIGTERM signals of startup process */ |
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void |
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HandleStartupProcInterrupts(void) |
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{ |
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/*
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* Check if we were requested to re-read config file. |
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*/ |
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if (got_SIGHUP) |
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{ |
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got_SIGHUP = false; |
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ProcessConfigFile(PGC_SIGHUP); |
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} |
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/*
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* Check if we were requested to exit without finishing recovery. |
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*/ |
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if (shutdown_requested) |
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proc_exit(1); |
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/*
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* Emergency bailout if postmaster has died. This is to avoid the |
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* necessity for manual cleanup of all postmaster children. |
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*/ |
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if (IsUnderPostmaster && !PostmasterIsAlive()) |
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exit(1); |
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} |
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/* ----------------------------------
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* Startup Process main entry point |
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* ---------------------------------- |
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*/ |
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void |
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StartupProcessMain(void) |
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{ |
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/*
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* If possible, make this process a group leader, so that the postmaster |
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* can signal any child processes too. |
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*/ |
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#ifdef HAVE_SETSID |
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if (setsid() < 0) |
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elog(FATAL, "setsid() failed: %m"); |
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#endif |
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/*
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* Properly accept or ignore signals the postmaster might send us. |
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* |
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* Note: ideally we'd not enable handle_standby_sig_alarm unless actually |
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* doing hot standby, but we don't know that yet. Rely on it to not do |
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* anything if it shouldn't. |
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*/ |
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pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */ |
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pqsignal(SIGINT, SIG_IGN); /* ignore query cancel */ |
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pqsignal(SIGTERM, StartupProcShutdownHandler); /* request shutdown */ |
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pqsignal(SIGQUIT, startupproc_quickdie); /* hard crash time */ |
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if (EnableHotStandby) |
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pqsignal(SIGALRM, handle_standby_sig_alarm); /* ignored unless
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* InHotStandby */ |
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else |
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pqsignal(SIGALRM, SIG_IGN); |
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pqsignal(SIGPIPE, SIG_IGN); |
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pqsignal(SIGUSR1, StartupProcSigUsr1Handler); |
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pqsignal(SIGUSR2, StartupProcTriggerHandler); |
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/*
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* Reset some signals that are accepted by postmaster but not here |
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*/ |
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pqsignal(SIGCHLD, SIG_DFL); |
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pqsignal(SIGTTIN, SIG_DFL); |
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pqsignal(SIGTTOU, SIG_DFL); |
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pqsignal(SIGCONT, SIG_DFL); |
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pqsignal(SIGWINCH, SIG_DFL); |
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/*
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* Unblock signals (they were blocked when the postmaster forked us) |
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*/ |
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PG_SETMASK(&UnBlockSig); |
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StartupXLOG(); |
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/*
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* Exit normally. Exit code 0 tells postmaster that we completed recovery |
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* successfully. |
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*/ |
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proc_exit(0); |
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} |
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void |
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PreRestoreCommand(void) |
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{ |
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/*
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* Set in_restore_command to tell the signal handler that we should exit |
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* right away on SIGTERM. We know that we're at a safe point to do that. |
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* Check if we had already received the signal, so that we don't miss a |
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* shutdown request received just before this. |
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*/ |
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in_restore_command = true; |
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if (shutdown_requested) |
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proc_exit(1); |
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} |
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void |
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PostRestoreCommand(void) |
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{ |
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in_restore_command = false; |
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} |
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bool |
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IsPromoteTriggered(void) |
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{ |
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return promote_triggered; |
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} |
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void |
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ResetPromoteTriggered(void) |
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{ |
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promote_triggered = false; |
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} |
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@ -0,0 +1,22 @@ |
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/*-------------------------------------------------------------------------
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* |
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* startup.h |
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* Exports from postmaster/startup.c. |
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* |
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* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group |
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* |
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* src/include/postmaster/startup.h |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef _STARTUP_H |
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#define _STARTUP_H |
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extern void HandleStartupProcInterrupts(void); |
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extern void StartupProcessMain(void); |
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extern void PreRestoreCommand(void); |
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extern void PostRestoreCommand(void); |
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extern bool IsPromoteTriggered(void); |
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extern void ResetPromoteTriggered(void); |
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#endif /* _STARTUP_H */ |
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