Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  * auxprocess.c
       3              :  *    functions related to auxiliary processes.
       4              :  *
       5              :  *
       6              :  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
       7              :  * Portions Copyright (c) 1994, Regents of the University of California
       8              :  *
       9              :  * IDENTIFICATION
      10              :  *    src/backend/postmaster/auxprocess.c
      11              :  *-------------------------------------------------------------------------
      12              :  */
      13              : #include "postgres.h"
      14              : 
      15              : #include <unistd.h>
      16              : #include <signal.h>
      17              : 
      18              : #include "miscadmin.h"
      19              : #include "pgstat.h"
      20              : #include "postmaster/auxprocess.h"
      21              : #include "storage/condition_variable.h"
      22              : #include "storage/ipc.h"
      23              : #include "storage/proc.h"
      24              : #include "storage/procsignal.h"
      25              : #include "utils/memutils.h"
      26              : #include "utils/ps_status.h"
      27              : 
      28              : 
      29              : static void ShutdownAuxiliaryProcess(int code, Datum arg);
      30              : 
      31              : 
      32              : /*
      33              :  *   AuxiliaryProcessMainCommon
      34              :  *
      35              :  *   Common initialization code for auxiliary processes, such as the bgwriter,
      36              :  *   walwriter, walreceiver, and the startup process.
      37              :  */
      38              : void
      39         4531 : AuxiliaryProcessMainCommon(void)
      40              : {
      41              :     Assert(IsUnderPostmaster);
      42              : 
      43              :     /* Release postmaster's working memory context */
      44         4531 :     if (PostmasterContext)
      45              :     {
      46         4531 :         MemoryContextDelete(PostmasterContext);
      47         4531 :         PostmasterContext = NULL;
      48              :     }
      49              : 
      50         4531 :     init_ps_display(NULL);
      51              : 
      52              :     Assert(GetProcessingMode() == InitProcessing);
      53              : 
      54         4531 :     IgnoreSystemIndexes = true;
      55              : 
      56              :     /*
      57              :      * As an auxiliary process, we aren't going to do the full InitPostgres
      58              :      * pushups, but there are a couple of things that need to get lit up even
      59              :      * in an auxiliary process.
      60              :      */
      61              : 
      62              :     /*
      63              :      * Create a PGPROC so we can use LWLocks and access shared memory.
      64              :      */
      65         4531 :     InitAuxiliaryProcess();
      66              : 
      67         4531 :     BaseInit();
      68              : 
      69         4531 :     ProcSignalInit(NULL, 0);
      70              : 
      71              :     /*
      72              :      * Auxiliary processes don't run transactions, but they may need a
      73              :      * resource owner anyway to manage buffer pins acquired outside
      74              :      * transactions (and, perhaps, other things in future).
      75              :      */
      76         4531 :     CreateAuxProcessResourceOwner();
      77              : 
      78              : 
      79              :     /* Initialize backend status information */
      80         4531 :     pgstat_beinit();
      81         4531 :     pgstat_bestart_initial();
      82         4531 :     pgstat_bestart_final();
      83              : 
      84              :     /* register a before-shutdown callback for LWLock cleanup */
      85         4531 :     before_shmem_exit(ShutdownAuxiliaryProcess, 0);
      86              : 
      87         4531 :     SetProcessingMode(NormalProcessing);
      88         4531 : }
      89              : 
      90              : /*
      91              :  * Begin shutdown of an auxiliary process.  This is approximately the equivalent
      92              :  * of ShutdownPostgres() in postinit.c.  We can't run transactions in an
      93              :  * auxiliary process, so most of the work of AbortTransaction() is not needed,
      94              :  * but we do need to make sure we've released any LWLocks we are holding.
      95              :  * (This is only critical during an error exit.)
      96              :  */
      97              : static void
      98         4531 : ShutdownAuxiliaryProcess(int code, Datum arg)
      99              : {
     100         4531 :     LWLockReleaseAll();
     101         4531 :     ConditionVariableCancelSleep();
     102         4531 :     pgstat_report_wait_end();
     103         4531 : }