diff options
Diffstat (limited to 'src/backend/postmaster/checkpointer.c')
| -rw-r--r-- | src/backend/postmaster/checkpointer.c | 127 |
1 files changed, 95 insertions, 32 deletions
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c index dd2c8376c6e..b94f9cdff21 100644 --- a/src/backend/postmaster/checkpointer.c +++ b/src/backend/postmaster/checkpointer.c @@ -10,10 +10,13 @@ * fill WAL segments; the checkpointer itself doesn't watch for the * condition.) * - * Normal termination is by SIGUSR2, which instructs the checkpointer to - * execute a shutdown checkpoint and then exit(0). (All backends must be - * stopped before SIGUSR2 is issued!) Emergency termination is by SIGQUIT; - * like any backend, the checkpointer will simply abort and exit on SIGQUIT. + * The normal termination sequence is that checkpointer is instructed to + * execute the shutdown checkpoint by SIGINT. After that checkpointer waits + * to be terminated via SIGUSR2, which instructs the checkpointer to exit(0). + * All backends must be stopped before SIGINT or SIGUSR2 is issued! + * + * Emergency termination is by SIGQUIT; like any backend, the checkpointer + * will simply abort and exit on SIGQUIT. * * If the checkpointer exits unexpectedly, the postmaster treats that the same * as a backend crash: shared memory may be corrupted, so remaining backends @@ -51,6 +54,7 @@ #include "storage/fd.h" #include "storage/ipc.h" #include "storage/lwlock.h" +#include "storage/pmsignal.h" #include "storage/proc.h" #include "storage/procsignal.h" #include "storage/shmem.h" @@ -141,6 +145,7 @@ double CheckPointCompletionTarget = 0.9; * Private state */ static bool ckpt_active = false; +static volatile sig_atomic_t ShutdownXLOGPending = false; /* these values are valid when ckpt_active is true: */ static pg_time_t ckpt_start_time; @@ -159,6 +164,9 @@ static bool ImmediateCheckpointRequested(void); static bool CompactCheckpointerRequestQueue(void); static void UpdateSharedMemoryConfig(void); +/* Signal handlers */ +static void ReqShutdownXLOG(SIGNAL_ARGS); + /* * Main entry point for checkpointer process @@ -188,7 +196,7 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) * tell us it's okay to shut down (via SIGUSR2). */ pqsignal(SIGHUP, SignalHandlerForConfigReload); - pqsignal(SIGINT, SIG_IGN); + pqsignal(SIGINT, ReqShutdownXLOG); pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */ /* SIGQUIT handler was already set up by InitPostmasterChild */ pqsignal(SIGALRM, SIG_IGN); @@ -211,8 +219,11 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) * process during a normal shutdown, and since checkpointer is shut down * very late... * - * Walsenders are shut down after the checkpointer, but currently don't - * report stats. If that changes, we need a more complicated solution. + * While e.g. walsenders are active after the shutdown checkpoint has been + * written (and thus could produce more stats), checkpointer stays around + * after the shutdown checkpoint has been written. postmaster will only + * signal checkpointer to exit after all processes that could emit stats + * have been shut down. */ before_shmem_exit(pgstat_before_server_shutdown, 0); @@ -327,7 +338,8 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) ProcGlobal->checkpointerProc = MyProcNumber; /* - * Loop forever + * Loop until we've been asked to write the shutdown checkpoint or + * terminate. */ for (;;) { @@ -346,7 +358,10 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) * Process any requests or signals received recently. */ AbsorbSyncRequests(); + HandleCheckpointerInterrupts(); + if (ShutdownXLOGPending || ShutdownRequestPending) + break; /* * Detect a pending checkpoint request by checking whether the flags @@ -517,8 +532,13 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) ckpt_active = false; - /* We may have received an interrupt during the checkpoint. */ + /* + * We may have received an interrupt during the checkpoint and the + * latch might have been reset (e.g. in CheckpointWriteDelay). + */ HandleCheckpointerInterrupts(); + if (ShutdownXLOGPending || ShutdownRequestPending) + break; } /* Check for archive_timeout and switch xlog files if necessary. */ @@ -557,6 +577,57 @@ CheckpointerMain(char *startup_data, size_t startup_data_len) cur_timeout * 1000L /* convert to ms */ , WAIT_EVENT_CHECKPOINTER_MAIN); } + + /* + * From here on, elog(ERROR) should end with exit(1), not send control + * back to the sigsetjmp block above. + */ + ExitOnAnyError = true; + + if (ShutdownXLOGPending) + { + /* + * Close down the database. + * + * Since ShutdownXLOG() creates restartpoint or checkpoint, and + * updates the statistics, increment the checkpoint request and flush + * out pending statistic. + */ + PendingCheckpointerStats.num_requested++; + ShutdownXLOG(0, 0); + pgstat_report_checkpointer(); + pgstat_report_wal(true); + + /* + * Tell postmaster that we're done. + */ + SendPostmasterSignal(PMSIGNAL_XLOG_IS_SHUTDOWN); + ShutdownXLOGPending = false; + } + + /* + * Wait until we're asked to shut down. By separating the writing of the + * shutdown checkpoint from checkpointer exiting, checkpointer can perform + * some should-be-as-late-as-possible work like writing out stats. + */ + for (;;) + { + /* Clear any already-pending wakeups */ + ResetLatch(MyLatch); + + HandleCheckpointerInterrupts(); + + if (ShutdownRequestPending) + break; + + (void) WaitLatch(MyLatch, + WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, + 0, + WAIT_EVENT_CHECKPOINTER_SHUTDOWN); + } + + /* Normal exit from the checkpointer is here */ + proc_exit(0); /* done */ } /* @@ -586,29 +657,6 @@ HandleCheckpointerInterrupts(void) */ UpdateSharedMemoryConfig(); } - if (ShutdownRequestPending) - { - /* - * From here on, elog(ERROR) should end with exit(1), not send control - * back to the sigsetjmp block above - */ - ExitOnAnyError = true; - - /* - * Close down the database. - * - * Since ShutdownXLOG() creates restartpoint or checkpoint, and - * updates the statistics, increment the checkpoint request and flush - * out pending statistic. - */ - PendingCheckpointerStats.num_requested++; - ShutdownXLOG(0, 0); - pgstat_report_checkpointer(); - pgstat_report_wal(true); - - /* Normal exit from the checkpointer is here */ - proc_exit(0); /* done */ - } /* Perform logging of memory contexts of this process */ if (LogMemoryContextPending) @@ -729,6 +777,7 @@ CheckpointWriteDelay(int flags, double progress) * in which case we just try to catch up as quickly as possible. */ if (!(flags & CHECKPOINT_IMMEDIATE) && + !ShutdownXLOGPending && !ShutdownRequestPending && !ImmediateCheckpointRequested() && IsCheckpointOnSchedule(progress)) @@ -858,6 +907,20 @@ IsCheckpointOnSchedule(double progress) /* -------------------------------- + * signal handler routines + * -------------------------------- + */ + +/* SIGINT: set flag to trigger writing of shutdown checkpoint */ +static void +ReqShutdownXLOG(SIGNAL_ARGS) +{ + ShutdownXLOGPending = true; + SetLatch(MyLatch); +} + + +/* -------------------------------- * communication with backends * -------------------------------- */ |