Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  * auxprocess.c
       3             :  *    functions related to auxiliary processes.
       4             :  *
       5             :  *
       6             :  * Portions Copyright (c) 1996-2025, 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        8118 : AuxiliaryProcessMainCommon(void)
      40             : {
      41             :     Assert(IsUnderPostmaster);
      42             : 
      43             :     /* Release postmaster's working memory context */
      44        8118 :     if (PostmasterContext)
      45             :     {
      46        8118 :         MemoryContextDelete(PostmasterContext);
      47        8118 :         PostmasterContext = NULL;
      48             :     }
      49             : 
      50        8118 :     init_ps_display(NULL);
      51             : 
      52             :     Assert(GetProcessingMode() == InitProcessing);
      53             : 
      54        8118 :     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        8118 :     InitAuxiliaryProcess();
      66             : 
      67        8118 :     BaseInit();
      68             : 
      69        8118 :     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        8118 :     CreateAuxProcessResourceOwner();
      77             : 
      78             : 
      79             :     /* Initialize backend status information */
      80        8118 :     pgstat_beinit();
      81        8118 :     pgstat_bestart_initial();
      82        8118 :     pgstat_bestart_final();
      83             : 
      84             :     /* register a before-shutdown callback for LWLock cleanup */
      85        8118 :     before_shmem_exit(ShutdownAuxiliaryProcess, 0);
      86             : 
      87        8118 :     SetProcessingMode(NormalProcessing);
      88        8118 : }
      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        8118 : ShutdownAuxiliaryProcess(int code, Datum arg)
      99             : {
     100        8118 :     LWLockReleaseAll();
     101        8118 :     ConditionVariableCancelSleep();
     102        8118 :     pgstat_report_wait_end();
     103        8118 : }