This reverts commits 0147fc7, 4567596, aa64f23, and 5ecd018. There is no longer agreement that introducing this function was the right way to address the problem. The consensus now seems to favor trying to make a correct value for MaxBackends available to mdules executing their _PG_init() functions. Nathan Bossart Discussion: http://postgr.es/m/20220323045229.i23skfscdbvrsuxa@jrouhaud
184 lines
4.5 KiB
C
184 lines
4.5 KiB
C
/*-------------------------------------------------------------------------
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* auxprocess.c
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* functions related to auxiliary processes.
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*
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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/auxprocess.c
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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 <signal.h>
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#include "libpq/pqsignal.h"
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "postmaster/auxprocess.h"
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#include "postmaster/bgwriter.h"
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#include "postmaster/startup.h"
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#include "postmaster/walwriter.h"
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#include "replication/walreceiver.h"
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#include "storage/bufmgr.h"
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#include "storage/bufpage.h"
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#include "storage/condition_variable.h"
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#include "storage/ipc.h"
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#include "storage/proc.h"
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#include "tcop/tcopprot.h"
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#include "utils/memutils.h"
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#include "utils/ps_status.h"
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#include "utils/rel.h"
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static void ShutdownAuxiliaryProcess(int code, Datum arg);
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/* ----------------
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* global variables
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* ----------------
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*/
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AuxProcType MyAuxProcType = NotAnAuxProcess; /* declared in miscadmin.h */
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/*
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* AuxiliaryProcessMain
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*
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* The main entry point for auxiliary processes, such as the bgwriter,
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* walwriter, walreceiver, bootstrapper and the shared memory checker code.
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*
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* This code is here just because of historical reasons.
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*/
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void
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AuxiliaryProcessMain(AuxProcType auxtype)
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{
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Assert(IsUnderPostmaster);
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MyAuxProcType = auxtype;
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switch (MyAuxProcType)
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{
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case StartupProcess:
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MyBackendType = B_STARTUP;
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break;
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case ArchiverProcess:
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MyBackendType = B_ARCHIVER;
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break;
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case BgWriterProcess:
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MyBackendType = B_BG_WRITER;
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break;
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case CheckpointerProcess:
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MyBackendType = B_CHECKPOINTER;
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break;
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case WalWriterProcess:
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MyBackendType = B_WAL_WRITER;
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break;
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case WalReceiverProcess:
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MyBackendType = B_WAL_RECEIVER;
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break;
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default:
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elog(ERROR, "something has gone wrong");
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MyBackendType = B_INVALID;
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}
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init_ps_display(NULL);
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SetProcessingMode(BootstrapProcessing);
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IgnoreSystemIndexes = true;
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/*
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* As an auxiliary process, we aren't going to do the full InitPostgres
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* pushups, but there are a couple of things that need to get lit up even
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* in an auxiliary process.
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*/
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/*
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* Create a PGPROC so we can use LWLocks. In the EXEC_BACKEND case, this
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* was already done by SubPostmasterMain().
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*/
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#ifndef EXEC_BACKEND
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InitAuxiliaryProcess();
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#endif
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BaseInit();
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/*
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* Assign the ProcSignalSlot for an auxiliary process. Since it doesn't
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* have a BackendId, the slot is statically allocated based on the
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* auxiliary process type (MyAuxProcType). Backends use slots indexed in
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* the range from 1 to MaxBackends (inclusive), so we use MaxBackends +
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* AuxProcType + 1 as the index of the slot for an auxiliary process.
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*
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* This will need rethinking if we ever want more than one of a particular
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* auxiliary process type.
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*/
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ProcSignalInit(MaxBackends + MyAuxProcType + 1);
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/*
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* Auxiliary processes don't run transactions, but they may need a
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* resource owner anyway to manage buffer pins acquired outside
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* transactions (and, perhaps, other things in future).
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*/
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CreateAuxProcessResourceOwner();
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/* Initialize backend status information */
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pgstat_beinit();
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pgstat_bestart();
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/* register a before-shutdown callback for LWLock cleanup */
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before_shmem_exit(ShutdownAuxiliaryProcess, 0);
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SetProcessingMode(NormalProcessing);
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switch (MyAuxProcType)
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{
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case StartupProcess:
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StartupProcessMain();
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proc_exit(1);
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case ArchiverProcess:
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PgArchiverMain();
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proc_exit(1);
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case BgWriterProcess:
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BackgroundWriterMain();
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proc_exit(1);
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case CheckpointerProcess:
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CheckpointerMain();
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proc_exit(1);
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case WalWriterProcess:
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WalWriterMain();
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proc_exit(1);
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case WalReceiverProcess:
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WalReceiverMain();
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proc_exit(1);
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default:
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elog(PANIC, "unrecognized process type: %d", (int) MyAuxProcType);
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proc_exit(1);
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}
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}
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/*
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* Begin shutdown of an auxiliary process. This is approximately the equivalent
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* of ShutdownPostgres() in postinit.c. We can't run transactions in an
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* auxiliary process, so most of the work of AbortTransaction() is not needed,
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* but we do need to make sure we've released any LWLocks we are holding.
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* (This is only critical during an error exit.)
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*/
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static void
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ShutdownAuxiliaryProcess(int code, Datum arg)
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{
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LWLockReleaseAll();
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ConditionVariableCancelSleep();
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pgstat_report_wait_end();
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}
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