mirror of https://github.com/postgres/postgres
This commit contains the basic, system-wide, infrastructure for
io_method=worker. It does not yet actually execute IO, this commit just
provides the infrastructure for running IO workers, kept separate for easier
review.
The number of IO workers can be adjusted with a PGC_SIGHUP GUC. Eventually
we'd like to make the number of workers dynamically scale up/down based on the
current "IO load".
To allow the number of IO workers to be increased without a restart, we need
to reserve PGPROC entries for the workers unconditionally. This has been
judged to be worth the cost. If it turns out to be problematic, we can
introduce a PGC_POSTMASTER GUC to control the maximum number.
As io workers might be needed during shutdown, e.g. for AIO during the
shutdown checkpoint, a new PMState phase is added. IO workers are shut down
after the shutdown checkpoint has been performed and walsender/archiver have
shut down, but before the checkpointer itself shuts down. See also
87a6690cc6.
Updates PGSTAT_FILE_FORMAT_ID due to the addition of a new BackendType.
Reviewed-by: Noah Misch <noah@leadboat.com>
Co-authored-by: Thomas Munro <thomas.munro@gmail.com>
Co-authored-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/uvrtrknj4kdytuboidbhwclo4gxhswwcpgadptsjvjqcluzmah%40brqs62irg4dt
Discussion: https://postgr.es/m/20210223100344.llw5an2aklengrmn@alap3.anarazel.de
Discussion: https://postgr.es/m/stj36ea6yyhoxtqkhpieia2z4krnam7qyetc57rfezgk4zgapf@gcnactj4z56m
pull/207/head
Andres Freund
9 months ago
parent
549ea06e42
commit
55b454d0e1
@ -0,0 +1,88 @@ |
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/*-------------------------------------------------------------------------
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* |
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* method_worker.c |
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* AIO - perform AIO using worker processes |
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* |
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* Portions Copyright (c) 1996-2025, 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/storage/aio/method_worker.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 "libpq/pqsignal.h" |
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#include "miscadmin.h" |
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#include "postmaster/auxprocess.h" |
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#include "postmaster/interrupt.h" |
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#include "storage/aio_subsys.h" |
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#include "storage/io_worker.h" |
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#include "storage/ipc.h" |
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#include "storage/latch.h" |
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#include "storage/proc.h" |
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#include "tcop/tcopprot.h" |
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#include "utils/wait_event.h" |
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/* GUCs */ |
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int io_workers = 3; |
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void |
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IoWorkerMain(const void *startup_data, size_t startup_data_len) |
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{ |
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sigjmp_buf local_sigjmp_buf; |
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MyBackendType = B_IO_WORKER; |
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AuxiliaryProcessMainCommon(); |
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pqsignal(SIGHUP, SignalHandlerForConfigReload); |
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pqsignal(SIGINT, die); /* to allow manually triggering worker restart */ |
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/*
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* Ignore SIGTERM, will get explicit shutdown via SIGUSR2 later in the |
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* shutdown sequence, similar to checkpointer. |
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*/ |
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pqsignal(SIGTERM, SIG_IGN); |
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/* SIGQUIT handler was already set up by InitPostmasterChild */ |
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pqsignal(SIGALRM, SIG_IGN); |
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pqsignal(SIGPIPE, SIG_IGN); |
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pqsignal(SIGUSR1, procsignal_sigusr1_handler); |
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pqsignal(SIGUSR2, SignalHandlerForShutdownRequest); |
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/* see PostgresMain() */ |
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if (sigsetjmp(local_sigjmp_buf, 1) != 0) |
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{ |
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error_context_stack = NULL; |
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HOLD_INTERRUPTS(); |
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EmitErrorReport(); |
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proc_exit(1); |
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} |
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/* We can now handle ereport(ERROR) */ |
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PG_exception_stack = &local_sigjmp_buf; |
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sigprocmask(SIG_SETMASK, &UnBlockSig, NULL); |
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while (!ShutdownRequestPending) |
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{ |
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WaitLatch(MyLatch, WL_LATCH_SET | WL_EXIT_ON_PM_DEATH, -1, |
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WAIT_EVENT_IO_WORKER_MAIN); |
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ResetLatch(MyLatch); |
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CHECK_FOR_INTERRUPTS(); |
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} |
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proc_exit(0); |
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} |
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bool |
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pgaio_workers_enabled(void) |
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{ |
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/* placeholder for future commit */ |
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return 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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* io_worker.h |
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* IO worker for implementing AIO "ourselves" |
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* |
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* |
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* Portions Copyright (c) 1996-2025, 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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* src/include/storage/io.h |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef IO_WORKER_H |
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#define IO_WORKER_H |
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pg_noreturn extern void IoWorkerMain(const void *startup_data, size_t startup_data_len); |
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extern PGDLLIMPORT int io_workers; |
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#endif /* IO_WORKER_H */ |
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