diff options
Diffstat (limited to 'src/backend/postmaster/postmaster.c')
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 811 |
1 files changed, 329 insertions, 482 deletions
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index 89a22815098..e7186c01b39 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -37,14 +37,13 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.399 2004/05/28 15:14:03 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.400 2004/05/29 22:48:19 tgl Exp $ * * NOTES * * Initialization: - * The Postmaster sets up a few shared memory data structures - * for the backends. It should at the very least initialize the - * lock manager. + * The Postmaster sets up shared memory data structures + * for the backends. * * Synchronization: * The Postmaster shares memory with the backends but should avoid @@ -97,6 +96,7 @@ #include "libpq/pqsignal.h" #include "miscadmin.h" #include "nodes/nodes.h" +#include "postmaster/postmaster.h" #include "pgtime.h" #include "storage/fd.h" #include "storage/ipc.h" @@ -113,22 +113,14 @@ #include "pgstat.h" -#ifdef HAVE_SIGPROCMASK -sigset_t UnBlockSig, - BlockSig, - AuthBlockSig; - -#else -int UnBlockSig, - BlockSig, - AuthBlockSig; -#endif - /* * List of active backends (or child processes anyway; we don't actually * know whether a given child has become a backend or is still in the * authorization phase). This is used mainly to keep track of how many * children we have and send them appropriate signals when necessary. + * + * "Special" children such as the startup and bgwriter tasks are not in + * this list. */ typedef struct bkend { @@ -149,15 +141,6 @@ char *UnixSocketDir; char *ListenAddresses; /* - * MaxBackends is the limit on the number of backends we can start. - * Note that a larger MaxBackends value will increase the size of the - * shared memory area as well as cause the postmaster to grab more - * kernel semaphores, even if you never actually use that many - * backends. - */ -int MaxBackends; - -/* * ReservedBackends is the number of backends reserved for superuser use. * This number is taken out of the pool size given by MaxBackends so * number of backend slots available to non-superusers is @@ -196,9 +179,6 @@ bool SilentMode = false; /* silent mode (-S) */ int PreAuthDelay = 0; int AuthenticationTimeout = 60; -int CheckPointTimeout = 300; -int CheckPointWarning = 30; -time_t LastSignalledCheckpoint = 0; bool log_hostname; /* for ps display and logging */ bool Log_connections = false; @@ -209,13 +189,11 @@ char *rendezvous_name; /* list of library:init-function to be preloaded */ char *preload_libraries_string = NULL; -/* Startup/shutdown state */ +/* PIDs of special child processes; 0 when not running */ static pid_t StartupPID = 0, - ShutdownPID = 0, - CheckPointPID = 0, BgWriterPID = 0; -static time_t checkpointed = 0; +/* Startup/shutdown state */ #define NoShutdown 0 #define SmartShutdown 1 #define FastShutdown 2 @@ -232,7 +210,6 @@ bool ClientAuthInProgress = false; /* T during new-client * Also, the global MyCancelKey passes the cancel key assigned to a given * backend from the postmaster to that backend (via fork). */ - static unsigned int random_seed = 0; static int debug_flag = 0; @@ -263,6 +240,7 @@ static void reaper(SIGNAL_ARGS); static void sigusr1_handler(SIGNAL_ARGS); static void dummy_handler(SIGNAL_ARGS); static void CleanupProc(int pid, int exitstatus); +static void HandleChildCrash(int pid, int exitstatus); static void LogChildExit(int lev, const char *procname, int pid, int exitstatus); static int BackendRun(Port *port); @@ -280,7 +258,7 @@ static void RandomSalt(char *cryptSalt, char *md5Salt); static void SignalChildren(int signal); static int CountChildren(void); static bool CreateOptsFile(int argc, char *argv[], char *fullprogname); -static pid_t SSDataBase(int xlop); +static pid_t StartChildProcess(int xlop); static void postmaster_error(const char *fmt,...) /* This lets gcc check the format string for consistency. */ @@ -311,10 +289,8 @@ static void ShmemBackendArrayRemove(pid_t pid); #endif /* EXEC_BACKEND */ -#define StartupDataBase() SSDataBase(BS_XLOG_STARTUP) -#define CheckPointDataBase() SSDataBase(BS_XLOG_CHECKPOINT) -#define StartBackgroundWriter() SSDataBase(BS_XLOG_BGWRITER) -#define ShutdownDataBase() SSDataBase(BS_XLOG_SHUTDOWN) +#define StartupDataBase() StartChildProcess(BS_XLOG_STARTUP) +#define StartBackgroundWriter() StartChildProcess(BS_XLOG_BGWRITER) /* @@ -325,14 +301,13 @@ PostmasterMain(int argc, char *argv[]) { int opt; int status; - char original_extraoptions[MAXPGPATH]; char *potential_DataDir = NULL; int i; - *original_extraoptions = '\0'; - progname = get_progname(argv[0]); + MyProcPid = PostmasterPid = getpid(); + IsPostmasterEnvironment = true; /* @@ -359,8 +334,6 @@ PostmasterMain(int argc, char *argv[]) */ umask((mode_t) 0077); - MyProcPid = PostmasterPid = getpid(); - /* * Fire up essential subsystems: memory management */ @@ -470,12 +443,10 @@ PostmasterMain(int argc, char *argv[]) case 'o': /* - * Other options to pass to the backend on the command - * line -- useful only for debugging. + * Other options to pass to the backend on the command line */ strcat(ExtraOptions, " "); strcat(ExtraOptions, optarg); - strcpy(original_extraoptions, optarg); break; case 'p': SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV); @@ -656,7 +627,7 @@ PostmasterMain(int argc, char *argv[]) * We want to do this before we try to grab the input sockets, because * the data directory interlock is more reliable than the socket-file * interlock (thanks to whoever decided to put socket files in /tmp - * :-(). For the same reason, it's best to grab the TCP socket before + * :-(). For the same reason, it's best to grab the TCP socket(s) before * the Unix socket. */ CreateDataDirLockFile(DataDir, true); @@ -766,12 +737,13 @@ PostmasterMain(int argc, char *argv[]) BackendList = DLNewList(); #ifdef WIN32 - /* - * Initialize the child pid/HANDLE arrays + * Initialize the child pid/HANDLE arrays for signal handling. */ - win32_childPIDArray = (pid_t *) malloc(NUM_BACKENDARRAY_ELEMS * sizeof(pid_t)); - win32_childHNDArray = (HANDLE *) malloc(NUM_BACKENDARRAY_ELEMS * sizeof(HANDLE)); + win32_childPIDArray = (pid_t *) + malloc(NUM_BACKENDARRAY_ELEMS * sizeof(pid_t)); + win32_childHNDArray = (HANDLE *) + malloc(NUM_BACKENDARRAY_ELEMS * sizeof(HANDLE)); if (!win32_childPIDArray || !win32_childHNDArray) ereport(FATAL, (errcode(ERRCODE_OUT_OF_MEMORY), @@ -791,16 +763,16 @@ PostmasterMain(int argc, char *argv[]) * * CAUTION: when changing this list, check for side-effects on the signal * handling setup of child processes. See tcop/postgres.c, - * bootstrap/bootstrap.c, and postmaster/pgstat.c. + * bootstrap/bootstrap.c, postmaster/bgwriter.c, and postmaster/pgstat.c. */ pqinitmask(); PG_SETMASK(&BlockSig); pqsignal(SIGHUP, SIGHUP_handler); /* reread config file and have * children do same */ - pqsignal(SIGINT, pmdie); /* send SIGTERM and ShutdownDataBase */ + pqsignal(SIGINT, pmdie); /* send SIGTERM and shut down */ pqsignal(SIGQUIT, pmdie); /* send SIGQUIT and die */ - pqsignal(SIGTERM, pmdie); /* wait for children and ShutdownDataBase */ + pqsignal(SIGTERM, pmdie); /* wait for children and shut down */ pqsignal(SIGALRM, SIG_IGN); /* ignored */ pqsignal(SIGPIPE, SIG_IGN); /* ignored */ pqsignal(SIGUSR1, sigusr1_handler); /* message from child process */ @@ -823,19 +795,6 @@ PostmasterMain(int argc, char *argv[]) whereToSendOutput = None; /* - * On many platforms, the first call of localtime() incurs significant - * overhead to load timezone info from the system configuration files. - * By doing it once in the postmaster, we avoid having to do it in - * every started child process. The savings are not huge, but they - * add up... - */ - { - time_t now = time(NULL); - - (void) pg_localtime(&now); - } - - /* * Initialize and try to startup the statistics collector process */ pgstat_init(); @@ -956,10 +915,7 @@ reg_reply(DNSServiceRegistrationReplyErrorType errorCode, void *context) static void pmdaemonize(void) { -#ifdef WIN32 - /* not supported */ - elog(FATAL, "SilentMode not supported under WIN32"); -#else +#ifndef WIN32 int i; pid_t pid; @@ -989,7 +945,7 @@ pmdaemonize(void) setitimer(ITIMER_PROF, &prof_itimer, NULL); #endif - MyProcPid = getpid(); /* reset MyProcPid to child */ + MyProcPid = PostmasterPid = getpid(); /* reset PID vars to child */ /* GH: If there's no setsid(), we hopefully don't need silent mode. * Until there's a better solution. @@ -1007,7 +963,10 @@ pmdaemonize(void) dup2(i, 1); dup2(i, 2); close(i); -#endif +#else /* WIN32 */ + /* not supported */ + elog(FATAL, "SilentMode not supported under WIN32"); +#endif /* WIN32 */ } @@ -1053,19 +1012,21 @@ usage(const char *progname) /* - * Main loop of postmaster + * Main idle loop of postmaster */ static int ServerLoop(void) { fd_set readmask; int nSockets; - struct timeval now, + time_t now, + last_touch_time; + struct timeval earlier, later; struct timezone tz; - int i; - gettimeofday(&now, &tz); + gettimeofday(&earlier, &tz); + last_touch_time = time(NULL); nSockets = initMasks(&readmask); @@ -1074,70 +1035,32 @@ ServerLoop(void) Port *port; fd_set rmask; struct timeval timeout; + int selres; + int i; /* - * The timeout for the select() below is normally set on the basis - * of the time to the next checkpoint. However, if for some - * reason we don't have a next-checkpoint time, time out after 60 - * seconds. This keeps checkpoint scheduling from locking up when - * we get new connection requests infrequently (since we are - * likely to detect checkpoint completion just after enabling - * signals below, after we've already made the decision about how - * long to wait this time). + * Wait for something to happen. + * + * We wait at most one minute, to ensure that the other background + * tasks handled below get done even when no requests are arriving. */ + memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set)); + timeout.tv_sec = 60; timeout.tv_usec = 0; - if (CheckPointPID == 0 && checkpointed && - StartupPID == 0 && Shutdown == NoShutdown && - !FatalError && random_seed != 0) - { - time_t now = time(NULL); - - if (CheckPointTimeout + checkpointed > now) - { - /* - * Not time for checkpoint yet, so set select timeout - */ - timeout.tv_sec = CheckPointTimeout + checkpointed - now; - } - else - { - /* Time to make the checkpoint... */ - CheckPointPID = CheckPointDataBase(); - - /* - * if fork failed, schedule another try at 0.1 normal - * delay - */ - if (CheckPointPID == 0) - { - timeout.tv_sec = CheckPointTimeout / 10; - checkpointed = now + timeout.tv_sec - CheckPointTimeout; - } - } - } + PG_SETMASK(&UnBlockSig); - /* - * If no background writer process is running and we should do - * background writing, start one. It doesn't matter if this fails, - * we'll just try again later. - */ - if (BgWriterPID == 0 && BgWriterPercent > 0 && - StartupPID == 0 && Shutdown == NoShutdown && - !FatalError && random_seed != 0) - BgWriterPID = StartBackgroundWriter(); + selres = select(nSockets, &rmask, NULL, NULL, &timeout); /* - * Wait for something to happen. + * Block all signals until we wait again. (This makes it safe for + * our signal handlers to do nontrivial work.) */ - memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set)); - - PG_SETMASK(&UnBlockSig); + PG_SETMASK(&BlockSig); - if (select(nSockets, &rmask, NULL, NULL, &timeout) < 0) + if (selres < 0) { - PG_SETMASK(&BlockSig); if (errno == EINTR || errno == EWOULDBLOCK) continue; ereport(LOG, @@ -1147,63 +1070,85 @@ ServerLoop(void) } /* - * Block all signals until we wait again. (This makes it safe for - * our signal handlers to do nontrivial work.) - */ - PG_SETMASK(&BlockSig); - - /* - * Select a random seed at the time of first receiving a request. + * New connection pending on any of our sockets? If so, fork a + * child process to deal with it. */ - while (random_seed == 0) + if (selres > 0) { - gettimeofday(&later, &tz); - /* - * We are not sure how much precision is in tv_usec, so we - * swap the nibbles of 'later' and XOR them with 'now'. On the - * off chance that the result is 0, we loop until it isn't. + * Select a random seed at the time of first receiving a request. */ - random_seed = now.tv_usec ^ - ((later.tv_usec << 16) | - ((later.tv_usec >> 16) & 0xffff)); - } + while (random_seed == 0) + { + gettimeofday(&later, &tz); - /* - * New connection pending on any of our sockets? If so, fork a - * child process to deal with it. - */ - for (i = 0; i < MAXLISTEN; i++) - { - if (ListenSocket[i] == -1) - break; - if (FD_ISSET(ListenSocket[i], &rmask)) + /* + * We are not sure how much precision is in tv_usec, so we + * swap the nibbles of 'later' and XOR them with 'earlier'. On + * the off chance that the result is 0, we loop until it isn't. + */ + random_seed = earlier.tv_usec ^ + ((later.tv_usec << 16) | + ((later.tv_usec >> 16) & 0xffff)); + } + + for (i = 0; i < MAXLISTEN; i++) { - port = ConnCreate(ListenSocket[i]); - if (port) + if (ListenSocket[i] == -1) + break; + if (FD_ISSET(ListenSocket[i], &rmask)) { - BackendStartup(port); - - /* - * We no longer need the open socket or port structure - * in this process - */ - StreamClose(port->sock); - ConnFree(port); + port = ConnCreate(ListenSocket[i]); + if (port) + { + BackendStartup(port); + + /* + * We no longer need the open socket or port structure + * in this process + */ + StreamClose(port->sock); + ConnFree(port); + } } } } + /* + * If no background writer process is running, and we are not in + * a state that prevents it, start one. It doesn't matter if this + * fails, we'll just try again later. + */ + if (BgWriterPID == 0 && StartupPID == 0 && !FatalError) + { + BgWriterPID = StartBackgroundWriter(); + /* If shutdown is pending, set it going */ + if (Shutdown > NoShutdown && BgWriterPID != 0) + kill(BgWriterPID, SIGUSR2); + } + /* If we have lost the stats collector, try to start a new one */ if (!pgstat_is_running) pgstat_start(); + + /* + * Touch the socket and lock file at least every ten minutes, to ensure + * that they are not removed by overzealous /tmp-cleaning tasks. + */ + now = time(NULL); + if (now - last_touch_time >= 10 * 60) + { + TouchSocketFile(); + TouchSocketLockFile(); + last_touch_time = now; + } } } /* - * Initialise the masks for select() for the ports - * we are listening on. Return the number of sockets to listen on. + * Initialise the masks for select() for the ports we are listening on. + * Return the number of sockets to listen on. */ static int initMasks(fd_set *rmask) @@ -1543,14 +1488,7 @@ processCancelRequest(Port *port, void *pkt) backendPID = (int) ntohl(canc->backendPID); cancelAuthCode = (long) ntohl(canc->cancelAuthCode); - if (backendPID == CheckPointPID) - { - ereport(DEBUG2, - (errmsg_internal("ignoring cancel request for checkpoint process %d", - backendPID))); - return; - } - else if (backendPID == BgWriterPID) + if (backendPID == BgWriterPID) { ereport(DEBUG2, (errmsg_internal("ignoring cancel request for bgwriter process %d", @@ -1561,7 +1499,7 @@ processCancelRequest(Port *port, void *pkt) /* * See if we have a matching backend. In the EXEC_BACKEND case, we * can no longer access the postmaster's own backend list, and must - * rely on the backup array in shared memory. + * rely on the duplicate array in shared memory. */ #ifndef EXEC_BACKEND for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr)) @@ -1687,7 +1625,7 @@ ConnFree(Port *conn) * them open, of course. */ void -ClosePostmasterPorts(bool pgstat_too) +ClosePostmasterPorts(void) { int i; @@ -1700,10 +1638,6 @@ ClosePostmasterPorts(bool pgstat_too) ListenSocket[i] = -1; } } - - /* Close pgstat control sockets, unless we're starting pgstat itself */ - if (pgstat_too) - pgstat_close_sockets(); } @@ -1741,6 +1675,8 @@ SIGHUP_handler(SIGNAL_ARGS) (errmsg("received SIGHUP, reloading configuration files"))); ProcessConfigFile(PGC_SIGHUP); SignalChildren(SIGHUP); + if (BgWriterPID != 0) + kill(BgWriterPID, SIGHUP); load_hba(); load_ident(); @@ -1748,13 +1684,6 @@ SIGHUP_handler(SIGNAL_ARGS) /* Update the starting-point file for future children */ write_nondefault_variables(PGC_SIGHUP); #endif - - /* - * Tell the background writer to terminate so that we will start a - * new one with a possibly changed config - */ - if (BgWriterPID != 0) - kill(BgWriterPID, SIGTERM); } PG_SETMASK(&UnBlockSig); @@ -1780,11 +1709,10 @@ pmdie(SIGNAL_ARGS) switch (postgres_signal_arg) { case SIGTERM: - /* * Smart Shutdown: * - * Wait for children to end their work and ShutdownDataBase. + * Wait for children to end their work, then shut down. */ if (Shutdown >= SmartShutdown) break; @@ -1792,36 +1720,28 @@ pmdie(SIGNAL_ARGS) ereport(LOG, (errmsg("received smart shutdown request"))); - /* Must tell bgwriter to quit, or it never will... */ - if (BgWriterPID != 0) - kill(BgWriterPID, SIGTERM); - - if (DLGetHead(BackendList)) /* let reaper() handle this */ - break; + if (DLGetHead(BackendList)) + break; /* let reaper() handle this */ /* - * No children left. Shutdown data base system. + * No children left. Begin shutdown of data base system. */ - if (StartupPID > 0 || FatalError) /* let reaper() handle - * this */ - break; - if (ShutdownPID > 0) - { - elog(PANIC, "shutdown process %d already running", - (int) ShutdownPID); - abort(); - } - - ShutdownPID = ShutdownDataBase(); + if (StartupPID != 0 || FatalError) + break; /* let reaper() handle this */ + /* Start the bgwriter if not running */ + if (BgWriterPID == 0) + BgWriterPID = StartBackgroundWriter(); + /* And tell it to shut down */ + if (BgWriterPID != 0) + kill(BgWriterPID, SIGUSR2); break; case SIGINT: - /* * Fast Shutdown: * * Abort all children with SIGTERM (rollback active transactions - * and exit) and ShutdownDataBase when they are gone. + * and exit) and shut down when they are gone. */ if (Shutdown >= FastShutdown) break; @@ -1842,33 +1762,34 @@ pmdie(SIGNAL_ARGS) } /* - * No children left. Shutdown data base system. + * No children left. Begin shutdown of data base system. * - * Unlike the previous case, it is not an error for the shutdown - * process to be running already (we could get SIGTERM - * followed shortly later by SIGINT). + * Note: if we previously got SIGTERM then we may send SIGUSR2 + * to the bgwriter a second time here. This should be harmless. */ - if (StartupPID > 0 || FatalError) /* let reaper() handle - * this */ - break; - if (ShutdownPID == 0) - ShutdownPID = ShutdownDataBase(); + if (StartupPID != 0 || FatalError) + break; /* let reaper() handle this */ + /* Start the bgwriter if not running */ + if (BgWriterPID == 0) + BgWriterPID = StartBackgroundWriter(); + /* And tell it to shut down */ + if (BgWriterPID != 0) + kill(BgWriterPID, SIGUSR2); break; case SIGQUIT: - /* * Immediate Shutdown: * * abort all children with SIGQUIT and exit without attempt to - * properly shutdown data base system. + * properly shut down data base system. */ ereport(LOG, (errmsg("received immediate shutdown request"))); - if (ShutdownPID > 0) - kill(ShutdownPID, SIGQUIT); - if (StartupPID > 0) + if (StartupPID != 0) kill(StartupPID, SIGQUIT); + if (BgWriterPID != 0) + kill(BgWriterPID, SIGQUIT); if (DLGetHead(BackendList)) SignalChildren(SIGQUIT); ExitPostmaster(0); @@ -1939,22 +1860,11 @@ reaper(SIGNAL_ARGS) } /* - * Check if this child was a shutdown or startup process. + * Check if this child was a startup process. */ - if (ShutdownPID > 0 && pid == ShutdownPID) - { - if (exitstatus != 0) - { - LogChildExit(LOG, gettext("shutdown process"), - pid, exitstatus); - ExitPostmaster(1); - } - /* Normal postmaster exit is here */ - ExitPostmaster(0); - } - - if (StartupPID > 0 && pid == StartupPID) + if (StartupPID != 0 && pid == StartupPID) { + StartupPID = 0; if (exitstatus != 0) { LogChildExit(LOG, gettext("startup process"), @@ -1963,7 +1873,6 @@ reaper(SIGNAL_ARGS) (errmsg("aborting startup due to startup process failure"))); ExitPostmaster(1); } - StartupPID = 0; /* * Startup succeeded - we are done with system startup or recovery. @@ -1971,33 +1880,51 @@ reaper(SIGNAL_ARGS) FatalError = false; /* - * Arrange for first checkpoint to occur after standard delay. + * Crank up the background writer. It doesn't matter if this + * fails, we'll just try again later. */ - CheckPointPID = 0; - checkpointed = time(NULL); + Assert(BgWriterPID == 0); + BgWriterPID = StartBackgroundWriter(); /* * Go to shutdown mode if a shutdown request was pending. */ - if (Shutdown > NoShutdown) + if (Shutdown > NoShutdown && BgWriterPID != 0) + kill(BgWriterPID, SIGUSR2); + + continue; + } + + /* + * Was it the bgwriter? + */ + if (BgWriterPID != 0 && pid == BgWriterPID) + { + if (exitstatus == 0 && Shutdown > NoShutdown && + !FatalError && !DLGetHead(BackendList)) { - if (ShutdownPID > 0) - { - elog(PANIC, "startup process %d died while shutdown process %d already running", - pid, (int) ShutdownPID); - abort(); - } - ShutdownPID = ShutdownDataBase(); + /* + * Normal postmaster exit is here: we've seen normal + * exit of the bgwriter after it's been told to shut down. + * We expect that it wrote a shutdown checkpoint. (If + * for some reason it didn't, recovery will occur on next + * postmaster start.) + */ + ExitPostmaster(0); } - - goto reaper_done; + /* + * Any unexpected exit of the bgwriter is treated as a crash. + */ + LogChildExit(DEBUG2, gettext("background writer process"), + pid, exitstatus); + HandleChildCrash(pid, exitstatus); + continue; } /* - * Else do standard child cleanup. + * Else do standard backend child cleanup. */ CleanupProc(pid, exitstatus); - } /* loop over pending child-death reports */ if (FatalError) @@ -2006,7 +1933,7 @@ reaper(SIGNAL_ARGS) * Wait for all children exit, then reset shmem and * StartupDataBase. */ - if (DLGetHead(BackendList) || StartupPID > 0 || ShutdownPID > 0) + if (DLGetHead(BackendList) || StartupPID != 0 || BgWriterPID != 0) goto reaper_done; ereport(LOG, (errmsg("all server processes terminated; reinitializing"))); @@ -2021,11 +1948,14 @@ reaper(SIGNAL_ARGS) if (Shutdown > NoShutdown) { - if (DLGetHead(BackendList)) - goto reaper_done; - if (StartupPID > 0 || ShutdownPID > 0) + if (DLGetHead(BackendList) || StartupPID != 0) goto reaper_done; - ShutdownPID = ShutdownDataBase(); + /* Start the bgwriter if not running */ + if (BgWriterPID == 0) + BgWriterPID = StartBackgroundWriter(); + /* And tell it to shut down */ + if (BgWriterPID != 0) + kill(BgWriterPID, SIGUSR2); } reaper_done: @@ -2044,11 +1974,9 @@ static void CleanupProc(int pid, int exitstatus) /* child's exit status. */ { - Dlelem *curr, - *next; - Backend *bp; + Dlelem *curr; - LogChildExit(DEBUG2, gettext("child process"), pid, exitstatus); + LogChildExit(DEBUG2, gettext("server process"), pid, exitstatus); /* * If a backend dies in an ugly way (i.e. exit status not 0) then we @@ -2056,61 +1984,81 @@ CleanupProc(int pid, * we assume everything is hunky dory and simply remove the backend * from the active backend list. */ - if (exitstatus == 0) + if (exitstatus != 0) + { + HandleChildCrash(pid, exitstatus); + return; + } + + for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr)) { - curr = DLGetHead(BackendList); - while (curr) + Backend *bp = (Backend *) DLE_VAL(curr); + + if (bp->pid == pid) { - bp = (Backend *) DLE_VAL(curr); - if (bp->pid == pid) - { + DLRemove(curr); + free(bp); + DLFreeElem(curr); #ifdef EXEC_BACKEND - ShmemBackendArrayRemove(bp->pid); + ShmemBackendArrayRemove(pid); #endif - DLRemove(curr); - free(bp); - DLFreeElem(curr); - break; - } - curr = DLGetSucc(curr); - } - - if (pid == CheckPointPID) - { - CheckPointPID = 0; - if (!FatalError) - { - checkpointed = time(NULL); - } - } - else if (pid == BgWriterPID) - BgWriterPID = 0; - else + /* Tell the collector about backend termination */ pgstat_beterm(pid); - - return; + break; + } } +} - /* below here we're dealing with a non-normal exit */ +/* + * HandleChildCrash -- cleanup after failed backend or bgwriter. + * + * The objectives here are to clean up our local state about the child + * process, and to signal all other remaining children to quickdie. + */ +static void +HandleChildCrash(int pid, + int exitstatus) /* child's exit status. */ +{ + Dlelem *curr, + *next; + Backend *bp; - /* Make log entry unless we did so already */ + /* + * Make log entry unless there was a previous crash (if so, nonzero + * exit status is to be expected in SIGQUIT response; don't clutter log) + */ if (!FatalError) { LogChildExit(LOG, - (pid == CheckPointPID) ? gettext("checkpoint process") : - (pid == BgWriterPID) ? gettext("bgwriter process") : + (pid == BgWriterPID) ? + gettext("background writer process") : gettext("server process"), pid, exitstatus); ereport(LOG, - (errmsg("terminating any other active server processes"))); + (errmsg("terminating any other active server processes"))); } - curr = DLGetHead(BackendList); - while (curr) + /* Process regular backends */ + for (curr = DLGetHead(BackendList); curr; curr = next) { next = DLGetSucc(curr); bp = (Backend *) DLE_VAL(curr); - if (bp->pid != pid) + if (bp->pid == pid) + { + /* + * Found entry for freshly-dead backend, so remove it. + */ + DLRemove(curr); + free(bp); + DLFreeElem(curr); +#ifdef EXEC_BACKEND + ShmemBackendArrayRemove(pid); +#endif + /* Tell the collector about backend termination */ + pgstat_beterm(pid); + /* Keep looping so we can signal remaining backends */ + } + else { /* * This backend is still alive. Unless we did so already, @@ -2130,34 +2078,18 @@ CleanupProc(int pid, kill(bp->pid, (SendStop ? SIGSTOP : SIGQUIT)); } } - else - { - /* - * Found entry for freshly-dead backend, so remove it. - */ -#ifdef EXEC_BACKEND - ShmemBackendArrayRemove(bp->pid); -#endif - DLRemove(curr); - free(bp); - DLFreeElem(curr); - } - curr = next; } - if (pid == CheckPointPID) - { - CheckPointPID = 0; - checkpointed = 0; - } - else if (pid == BgWriterPID) + /* Take care of the bgwriter too */ + if (pid == BgWriterPID) BgWriterPID = 0; - else + else if (BgWriterPID != 0 && !FatalError) { - /* - * Tell the collector about backend termination - */ - pgstat_beterm(pid); + ereport(DEBUG2, + (errmsg_internal("sending %s to process %d", + (SendStop ? "SIGSTOP" : "SIGQUIT"), + (int) BgWriterPID))); + kill(BgWriterPID, (SendStop ? SIGSTOP : SIGQUIT)); } FatalError = true; @@ -2204,26 +2136,16 @@ LogChildExit(int lev, const char *procname, int pid, int exitstatus) static void SignalChildren(int signal) { - Dlelem *curr, - *next; - Backend *bp; + Dlelem *curr; - curr = DLGetHead(BackendList); - while (curr) + for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr)) { - next = DLGetSucc(curr); - bp = (Backend *) DLE_VAL(curr); + Backend *bp = (Backend *) DLE_VAL(curr); - if (bp->pid != MyProcPid) - { - ereport(DEBUG2, - (errmsg_internal("sending signal %d to process %d", - signal, - (int) bp->pid))); - kill(bp->pid, signal); - } - - curr = next; + ereport(DEBUG4, + (errmsg_internal("sending signal %d to process %d", + signal, (int) bp->pid))); + kill(bp->pid, signal); } } @@ -2346,10 +2268,10 @@ BackendStartup(Port *port) */ bn->pid = pid; bn->cancel_key = MyCancelKey; + DLAddHead(BackendList, DLNewElem(bn)); #ifdef EXEC_BACKEND ShmemBackendArrayAdd(bn); #endif - DLAddHead(BackendList, DLNewElem(bn)); return STATUS_OK; } @@ -2438,9 +2360,9 @@ BackendRun(Port *port) /* * Let's clean up ourselves as the postmaster child, and close the - * postmaster's other sockets + * postmaster's listen sockets */ - ClosePostmasterPorts(true); + ClosePostmasterPorts(); /* We don't want the postmaster's proc_exit() handlers */ on_exit_reset(); @@ -2833,23 +2755,23 @@ SubPostmasterMain(int argc, char *argv[]) if (strcmp(argv[1], "-forkboot") == 0) { /* Close the postmaster's sockets */ - ClosePostmasterPorts(true); + ClosePostmasterPorts(); /* Attach process to shared segments */ CreateSharedMemoryAndSemaphores(false, MaxBackends, 0); BootstrapMain(argc - 2, argv + 2); - ExitPostmaster(0); + proc_exit(0); } if (strcmp(argv[1], "-forkbuf") == 0) { /* Close the postmaster's sockets */ - ClosePostmasterPorts(false); + ClosePostmasterPorts(); /* Do not want to attach to shared memory */ PgstatBufferMain(argc, argv); - ExitPostmaster(0); + proc_exit(0); } if (strcmp(argv[1], "-forkcol") == 0) { @@ -2861,7 +2783,7 @@ SubPostmasterMain(int argc, char *argv[]) /* Do not want to attach to shared memory */ PgstatCollectorMain(argc, argv); - ExitPostmaster(0); + proc_exit(0); } return 1; /* shouldn't get here */ @@ -2886,8 +2808,6 @@ ExitPostmaster(int status) * * MUST -- vadim 05-10-1999 */ - /* Should I use true instead? */ - ClosePostmasterPorts(false); proc_exit(status); } @@ -2902,45 +2822,6 @@ sigusr1_handler(SIGNAL_ARGS) PG_SETMASK(&BlockSig); - if (CheckPostmasterSignal(PMSIGNAL_DO_CHECKPOINT)) - { - if (CheckPointWarning != 0) - { - /* - * This only times checkpoints forced by running out of - * segment files. Other checkpoints could reduce the - * frequency of forced checkpoints. - */ - time_t now = time(NULL); - - if (LastSignalledCheckpoint != 0) - { - int elapsed_secs = now - LastSignalledCheckpoint; - - if (elapsed_secs < CheckPointWarning) - ereport(LOG, - (errmsg("checkpoints are occurring too frequently (%d seconds apart)", - elapsed_secs), - errhint("Consider increasing the configuration parameter \"checkpoint_segments\"."))); - } - LastSignalledCheckpoint = now; - } - - /* - * Request to schedule a checkpoint - * - * Ignore request if checkpoint is already running or checkpointing - * is currently disabled - */ - if (CheckPointPID == 0 && checkpointed && - StartupPID == 0 && Shutdown == NoShutdown && - !FatalError && random_seed != 0) - { - CheckPointPID = CheckPointDataBase(); - /* note: if fork fails, CheckPointPID stays 0; nothing happens */ - } - } - if (CheckPostmasterSignal(PMSIGNAL_PASSWORD_CHANGE)) { /* @@ -2957,7 +2838,7 @@ sigusr1_handler(SIGNAL_ARGS) * CatchupInterruptHandler). See storage/ipc/sinval[adt].c for the * use of this. */ - if (Shutdown == NoShutdown) + if (Shutdown <= SmartShutdown) SignalChildren(SIGUSR1); } @@ -2971,9 +2852,10 @@ sigusr1_handler(SIGNAL_ARGS) * Dummy signal handler * * We use this for signals that we don't actually use in the postmaster, - * but we do use in backends. If we SIG_IGN such signals in the postmaster, - * then a newly started backend might drop a signal that arrives before it's - * able to reconfigure its signal processing. (See notes in postgres.c.) + * but we do use in backends. If we were to SIG_IGN such signals in the + * postmaster, then a newly started backend might drop a signal that arrives + * before it's able to reconfigure its signal processing. (See notes in + * tcop/postgres.c.) */ static void dummy_handler(SIGNAL_ARGS) @@ -3057,37 +2939,28 @@ static int CountChildren(void) { Dlelem *curr; - Backend *bp; int cnt = 0; for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr)) { - bp = (Backend *) DLE_VAL(curr); - if (bp->pid != MyProcPid) - cnt++; - } - /* Checkpoint and bgwriter will be in the list, discount them */ - if (CheckPointPID != 0) - cnt--; - if (BgWriterPID != 0) - cnt--; + cnt++; + } return cnt; } /* - * SSDataBase -- start a non-backend child process for the postmaster + * StartChildProcess -- start a non-backend child process for the postmaster * * xlog determines what kind of child will be started. All child types * initially go to BootstrapMain, which will handle common setup. * - * Return value of SSDataBase is subprocess' PID, or 0 if failed to start - * subprocess (0 is returned only for checkpoint/bgwriter cases). + * Return value of StartChildProcess is subprocess' PID, or 0 if failed + * to start subprocess. */ static pid_t -SSDataBase(int xlop) +StartChildProcess(int xlop) { - Backend *bn; pid_t pid; char *av[10]; int ac = 0; @@ -3153,7 +3026,7 @@ SSDataBase(int xlop) IsUnderPostmaster = true; /* we are a postmaster subprocess now */ /* Close the postmaster's sockets */ - ClosePostmasterPorts(true); + ClosePostmasterPorts(); /* Lose the postmaster's on-exit routines and port connections */ on_exit_reset(); @@ -3180,17 +3053,9 @@ SSDataBase(int xlop) ereport(LOG, (errmsg("could not fork startup process: %m"))); break; - case BS_XLOG_CHECKPOINT: - ereport(LOG, - (errmsg("could not fork checkpoint process: %m"))); - break; case BS_XLOG_BGWRITER: ereport(LOG, - (errmsg("could not fork bgwriter process: %m"))); - break; - case BS_XLOG_SHUTDOWN: - ereport(LOG, - (errmsg("could not fork shutdown process: %m"))); + (errmsg("could not fork background writer process: %m"))); break; default: ereport(LOG, @@ -3199,50 +3064,17 @@ SSDataBase(int xlop) } /* - * fork failure is fatal during startup/shutdown, but there's no - * need to choke if a routine checkpoint or starting a background - * writer fails. + * fork failure is fatal during startup, but there's no need + * to choke immediately if starting other child types fails. */ - if (xlop == BS_XLOG_CHECKPOINT) - return 0; - if (xlop == BS_XLOG_BGWRITER) - return 0; - ExitPostmaster(1); + if (xlop == BS_XLOG_STARTUP) + ExitPostmaster(1); + return 0; } /* * in parent, successful fork - * - * The startup and shutdown processes are not considered normal - * backends, but the checkpoint and bgwriter processes are. They must - * be added to the list of backends. */ - if (xlop == BS_XLOG_CHECKPOINT || xlop == BS_XLOG_BGWRITER) - { - if (!(bn = (Backend *) malloc(sizeof(Backend)))) - { - ereport(LOG, - (errcode(ERRCODE_OUT_OF_MEMORY), - errmsg("out of memory"))); - ExitPostmaster(1); - } - - bn->pid = pid; - bn->cancel_key = PostmasterRandom(); -#ifdef EXEC_BACKEND - ShmemBackendArrayAdd(bn); -#endif - DLAddHead(BackendList, DLNewElem(bn)); - - /* - * Since this code is executed periodically, it's a fine place to - * do other actions that should happen every now and then on no - * particular schedule. Such as... - */ - TouchSocketFile(); - TouchSocketLockFile(); - } - return pid; } @@ -3316,6 +3148,8 @@ extern int pgStatSock; #define write_var(var,fp) fwrite((void*)&(var),sizeof(var),1,fp) #define read_var(var,fp) fread((void*)&(var),sizeof(var),1,fp) +#define write_array_var(var,fp) fwrite((void*)(var),sizeof(var),1,fp) +#define read_array_var(var,fp) fread((void*)(var),sizeof(var),1,fp) static bool write_backend_variables(char *filename, Port *port) @@ -3326,9 +3160,9 @@ write_backend_variables(char *filename, Port *port) /* Calculate name for temp file in caller's buffer */ Assert(DataDir); - snprintf(filename, MAXPGPATH, "%s/%s/%s.backend_var.%lu", + snprintf(filename, MAXPGPATH, "%s/%s/%s.backend_var.%d.%lu", DataDir, PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX, - ++tmpBackendFileNum); + MyProcPid, ++tmpBackendFileNum); /* Open file */ fp = AllocateFile(filename, PG_BINARY_W); @@ -3366,7 +3200,9 @@ write_backend_variables(char *filename, Port *port) */ StrNCpy(str_buf, DataDir, MAXPGPATH); - fwrite((void *) str_buf, MAXPGPATH, 1, fp); + write_array_var(str_buf, fp); + + write_array_var(ListenSocket, fp); write_var(MyCancelKey, fp); @@ -3386,14 +3222,15 @@ write_backend_variables(char *filename, Port *port) write_var(debug_flag, fp); write_var(PostmasterPid, fp); - fwrite((void *) my_exec_path, MAXPGPATH, 1, fp); + StrNCpy(str_buf, my_exec_path, MAXPGPATH); + write_array_var(str_buf, fp); - fwrite((void *) ExtraOptions, sizeof(ExtraOptions), 1, fp); + write_array_var(ExtraOptions, fp); StrNCpy(str_buf, setlocale(LC_COLLATE, NULL), MAXPGPATH); - fwrite((void *) str_buf, MAXPGPATH, 1, fp); + write_array_var(str_buf, fp); StrNCpy(str_buf, setlocale(LC_CTYPE, NULL), MAXPGPATH); - fwrite((void *) str_buf, MAXPGPATH, 1, fp); + write_array_var(str_buf, fp); /* Release file */ if (FreeFile(fp)) @@ -3430,9 +3267,11 @@ read_backend_variables(char *filename, Port *port) read_var(port->cryptSalt, fp); read_var(port->md5Salt, fp); - fread((void *) str_buf, MAXPGPATH, 1, fp); + read_array_var(str_buf, fp); SetDataDir(str_buf); + read_array_var(ListenSocket, fp); + read_var(MyCancelKey, fp); read_var(UsedShmemSegID, fp); @@ -3451,13 +3290,14 @@ read_backend_variables(char *filename, Port *port) read_var(debug_flag, fp); read_var(PostmasterPid, fp); - fread((void *) my_exec_path, MAXPGPATH, 1, fp); + read_array_var(str_buf, fp); + StrNCpy(my_exec_path, str_buf, MAXPGPATH); - fread((void *) ExtraOptions, sizeof(ExtraOptions), 1, fp); + read_array_var(ExtraOptions, fp); - fread((void *) str_buf, MAXPGPATH, 1, fp); + read_array_var(str_buf, fp); setlocale(LC_COLLATE, str_buf); - fread((void *) str_buf, MAXPGPATH, 1, fp); + read_array_var(str_buf, fp); setlocale(LC_CTYPE, str_buf); /* Release file */ @@ -3481,6 +3321,7 @@ ShmemBackendArrayAllocation(void) size_t size = ShmemBackendArraySize(); ShmemBackendArray = (Backend *) ShmemAlloc(size); + /* Mark all slots as empty */ memset(ShmemBackendArray, 0, size); } @@ -3489,9 +3330,9 @@ ShmemBackendArrayAdd(Backend *bn) { int i; + /* Find an empty slot */ for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++) { - /* Find an empty slot */ if (ShmemBackendArray[i].pid == 0) { ShmemBackendArray[i] = *bn; @@ -3500,7 +3341,7 @@ ShmemBackendArrayAdd(Backend *bn) } ereport(FATAL, - (errmsg_internal("unable to add backend entry"))); + (errmsg_internal("no free slots in shmem backend array"))); } static void @@ -3597,13 +3438,14 @@ win32_forkexec(const char *path, char *argv[]) } /* - * Note: The following three functions must not be interrupted (eg. by signals). - * As the Postgres Win32 signalling architecture (currently) requires polling, - * or APC checking functions which aren't used here, this is not an issue. + * Note: The following three functions must not be interrupted (eg. by + * signals). As the Postgres Win32 signalling architecture (currently) + * requires polling, or APC checking functions which aren't used here, this + * is not an issue. * - * We keep two separate arrays, instead of a single array of pid/HANDLE structs, - * to avoid having to re-create a handle array for WaitForMultipleObjects on - * each call to win32_waitpid. + * We keep two separate arrays, instead of a single array of pid/HANDLE + * structs, to avoid having to re-create a handle array for + * WaitForMultipleObjects on each call to win32_waitpid. */ static void @@ -3662,15 +3504,17 @@ win32_waitpid(int *exitstatus) */ int index; DWORD exitCode; - DWORD ret = WaitForMultipleObjects(win32_numChildren, win32_childHNDArray, FALSE, 0); + DWORD ret; + ret = WaitForMultipleObjects(win32_numChildren, win32_childHNDArray, + FALSE, 0); switch (ret) { case WAIT_FAILED: - ereport(ERROR, - (errmsg_internal("failed to wait on %lu children: %i", + ereport(LOG, + (errmsg_internal("failed to wait on %lu children: %d", win32_numChildren, (int) GetLastError()))); - /* Fall through to WAIT_TIMEOUTs return */ + return -1; case WAIT_TIMEOUT: /* No children have finished */ @@ -3685,7 +3529,7 @@ win32_waitpid(int *exitstatus) index = ret - WAIT_OBJECT_0; Assert(index >= 0 && index < win32_numChildren); if (!GetExitCodeProcess(win32_childHNDArray[index], &exitCode)) - + { /* * If we get this far, this should never happen, but, * then again... No choice other than to assume a @@ -3694,6 +3538,7 @@ win32_waitpid(int *exitstatus) ereport(FATAL, (errmsg_internal("failed to get exit code for child %lu", win32_childPIDArray[index]))); + } *exitstatus = (int) exitCode; return win32_childPIDArray[index]; } @@ -3703,8 +3548,10 @@ win32_waitpid(int *exitstatus) return -1; } -/* Note! Code belows executes on separate threads, one for - each child process created */ +/* + * Note! Code below executes on separate threads, one for + * each child process created + */ static DWORD WINAPI win32_sigchld_waiter(LPVOID param) { |