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/*-------------------------------------------------------------------------
* auxprocess.c
* functions related to auxiliary processes.
*
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/postmaster/auxprocess.c
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <unistd.h>
#include <signal.h>
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/auxprocess.h"
#include "postmaster/bgwriter.h"
#include "postmaster/startup.h"
#include "postmaster/walsummarizer.h"
#include "postmaster/walwriter.h"
#include "replication/walreceiver.h"
#include "storage/condition_variable.h"
#include "storage/ipc.h"
#include "storage/proc.h"
#include "storage/procsignal.h"
#include "utils/ps_status.h"
static void ShutdownAuxiliaryProcess(int code, Datum arg);
/*
* AuxiliaryProcessMain
*
* The main entry point for auxiliary processes, such as the bgwriter,
* walwriter, walreceiver, bootstrapper and the shared memory checker code.
*
* This code is here just because of historical reasons.
*/
void
AuxiliaryProcessMain(BackendType auxtype)
{
Assert(IsUnderPostmaster);
MyBackendType = auxtype;
init_ps_display(NULL);
SetProcessingMode(BootstrapProcessing);
IgnoreSystemIndexes = true;
/*
* As an auxiliary process, we aren't going to do the full InitPostgres
* pushups, but there are a couple of things that need to get lit up even
* in an auxiliary process.
*/
/*
* Create a PGPROC so we can use LWLocks and access shared memory.
*/
InitAuxiliaryProcess();
BaseInit();
ProcSignalInit();
/*
* Auxiliary processes don't run transactions, but they may need a
* resource owner anyway to manage buffer pins acquired outside
* transactions (and, perhaps, other things in future).
*/
CreateAuxProcessResourceOwner();
/* Initialize backend status information */
pgstat_beinit();
pgstat_bestart();
/* register a before-shutdown callback for LWLock cleanup */
before_shmem_exit(ShutdownAuxiliaryProcess, 0);
SetProcessingMode(NormalProcessing);
switch (MyBackendType)
{
case B_STARTUP:
StartupProcessMain();
proc_exit(1);
case B_ARCHIVER:
PgArchiverMain();
proc_exit(1);
case B_BG_WRITER:
BackgroundWriterMain();
proc_exit(1);
case B_CHECKPOINTER:
CheckpointerMain();
proc_exit(1);
case B_WAL_WRITER:
WalWriterMain();
proc_exit(1);
case B_WAL_RECEIVER:
WalReceiverMain();
proc_exit(1);
case B_WAL_SUMMARIZER:
WalSummarizerMain();
proc_exit(1);
default:
elog(PANIC, "unrecognized process type: %d", (int) MyBackendType);
proc_exit(1);
}
}
/*
* Begin shutdown of an auxiliary process. This is approximately the equivalent
* of ShutdownPostgres() in postinit.c. We can't run transactions in an
* auxiliary process, so most of the work of AbortTransaction() is not needed,
* but we do need to make sure we've released any LWLocks we are holding.
* (This is only critical during an error exit.)
*/
static void
ShutdownAuxiliaryProcess(int code, Datum arg)
{
LWLockReleaseAll();
ConditionVariableCancelSleep();
pgstat_report_wait_end();
}
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