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5891c7a8ed
Previously the statistics collector received statistics updates via UDP and shared statistics data by writing them out to temporary files regularly. These files can reach tens of megabytes and are written out up to twice a second. This has repeatedly prevented us from adding additional useful statistics. Now statistics are stored in shared memory. Statistics for variable-numbered objects are stored in a dshash hashtable (backed by dynamic shared memory). Fixed-numbered stats are stored in plain shared memory. The header for pgstat.c contains an overview of the architecture. The stats collector is not needed anymore, remove it. By utilizing the transactional statistics drop infrastructure introduced in a prior commit statistics entries cannot "leak" anymore. Previously leaked statistics were dropped by pgstat_vacuum_stat(), called from [auto-]vacuum. On systems with many small relations pgstat_vacuum_stat() could be quite expensive. Now that replicas drop statistics entries for dropped objects, it is not necessary anymore to reset stats when starting from a cleanly shut down replica. Subsequent commits will perform some further code cleanup, adapt docs and add tests. Bumps PGSTAT_FILE_FORMAT_ID. Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-By: Andres Freund <andres@anarazel.de> Reviewed-By: Thomas Munro <thomas.munro@gmail.com> Reviewed-By: Justin Pryzby <pryzby@telsasoft.com> Reviewed-By: "David G. Johnston" <david.g.johnston@gmail.com> Reviewed-By: Tomas Vondra <tomas.vondra@2ndquadrant.com> (in a much earlier version) Reviewed-By: Arthur Zakirov <a.zakirov@postgrespro.ru> (in a much earlier version) Reviewed-By: Antonin Houska <ah@cybertec.at> (in a much earlier version) Discussion: https://postgr.es/m/20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de Discussion: https://postgr.es/m/20220308205351.2xcn6k4x5yivcxyd@alap3.anarazel.de Discussion: https://postgr.es/m/20210319235115.y3wz7hpnnrshdyv6@alap3.anarazel.de
117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* interrupt.c
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* Interrupt handling routines.
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*
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* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* src/backend/postmaster/interrupt.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 <unistd.h>
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#include "miscadmin.h"
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#include "postmaster/interrupt.h"
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#include "storage/ipc.h"
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#include "storage/latch.h"
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#include "storage/procsignal.h"
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#include "utils/guc.h"
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#include "utils/memutils.h"
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volatile sig_atomic_t ConfigReloadPending = false;
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volatile sig_atomic_t ShutdownRequestPending = false;
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/*
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* Simple interrupt handler for main loops of background processes.
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*/
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void
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HandleMainLoopInterrupts(void)
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{
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if (ProcSignalBarrierPending)
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ProcessProcSignalBarrier();
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if (ConfigReloadPending)
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{
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ConfigReloadPending = false;
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ProcessConfigFile(PGC_SIGHUP);
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}
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if (ShutdownRequestPending)
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proc_exit(0);
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/* Perform logging of memory contexts of this process */
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if (LogMemoryContextPending)
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ProcessLogMemoryContextInterrupt();
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}
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/*
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* Simple signal handler for triggering a configuration reload.
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*
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* Normally, this handler would be used for SIGHUP. The idea is that code
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* which uses it would arrange to check the ConfigReloadPending flag at
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* convenient places inside main loops, or else call HandleMainLoopInterrupts.
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*/
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void
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SignalHandlerForConfigReload(SIGNAL_ARGS)
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{
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int save_errno = errno;
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ConfigReloadPending = true;
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SetLatch(MyLatch);
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errno = save_errno;
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}
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/*
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* Simple signal handler for exiting quickly as if due to a crash.
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*
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* Normally, this would be used for handling SIGQUIT.
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*/
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void
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SignalHandlerForCrashExit(SIGNAL_ARGS)
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{
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/*
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* We DO NOT want to run proc_exit() or atexit() callbacks -- we're here
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* because shared memory may be corrupted, so we don't want to try to
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* clean up our transaction. Just nail the windows shut and get out of
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* town. The callbacks wouldn't be safe to run from a signal handler,
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* anyway.
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*
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* Note we do _exit(2) not _exit(0). This is to force the postmaster into
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* a system reset cycle if someone 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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/*
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* Simple signal handler for triggering a long-running background process to
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* shut down and exit.
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*
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* Typically, this handler would be used for SIGTERM, but some processes use
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* other signals. In particular, the checkpointer exits on SIGUSR2, and the
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* WAL writer exits on either SIGINT or SIGTERM.
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*
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* ShutdownRequestPending should be checked at a convenient place within the
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* main loop, or else the main loop should call HandleMainLoopInterrupts.
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*/
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void
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SignalHandlerForShutdownRequest(SIGNAL_ARGS)
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{
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int save_errno = errno;
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ShutdownRequestPending = true;
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SetLatch(MyLatch);
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errno = save_errno;
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}
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