src/backend/utils/activity/wait_event_funcs.c

   1 /*------------------------------------------------------------------------
   2  *
   3  * wait_event_funcs.c
   4  *        Functions for accessing wait event data.
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/utils/activity/wait_event_funcs.c
  12  *
  13  *------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "funcapi.h"
  18 #include "utils/builtins.h"
  19 #include "utils/wait_event.h"
  20
  21 /*
  22  * Each wait event has one corresponding entry in this structure, fed to
  23  * the SQL function of this file.
  24  */
  25 static const struct
  26 {
  27         const char *type;
  28         const char *name;
  29         const char *description;
  30 }
  31
  32                         waitEventData[] =
  33 {
  34 #include "wait_event_funcs_data.c"
  35         /* end of list */
  36         {NULL, NULL, NULL}
  37 };
  38
  39
  40 /*
  41  * pg_get_wait_events
  42  *
  43  * List information about wait events (type, name and description).
  44  */
  45 Datum
  46 pg_get_wait_events(PG_FUNCTION_ARGS)
  47 {
  48 #define PG_GET_WAIT_EVENTS_COLS 3
  49         ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
  50         char      **waiteventnames;
  51         int                     nbwaitevents;
  52
  53         /* Build tuplestore to hold the result rows */
  54         InitMaterializedSRF(fcinfo, 0);
  55
  56         /* Iterate over the list of wait events */
  57         for (int idx = 0; waitEventData[idx].type != NULL; idx++)
  58         {
  59                 Datum           values[PG_GET_WAIT_EVENTS_COLS] = {0};
  60                 bool            nulls[PG_GET_WAIT_EVENTS_COLS] = {0};
  61
  62                 values[0] = CStringGetTextDatum(waitEventData[idx].type);
  63                 values[1] = CStringGetTextDatum(waitEventData[idx].name);
  64                 values[2] = CStringGetTextDatum(waitEventData[idx].description);
  65
  66                 tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
  67         }
  68
  69         /* Handle custom wait events for extensions */
  70         waiteventnames = GetWaitEventCustomNames(PG_WAIT_EXTENSION,
  71                                                                                          &nbwaitevents);
  72
  73         for (int idx = 0; idx < nbwaitevents; idx++)
  74         {
  75                 StringInfoData buf;
  76                 Datum           values[PG_GET_WAIT_EVENTS_COLS] = {0};
  77                 bool            nulls[PG_GET_WAIT_EVENTS_COLS] = {0};
  78
  79
  80                 values[0] = CStringGetTextDatum("Extension");
  81                 values[1] = CStringGetTextDatum(waiteventnames[idx]);
  82
  83                 initStringInfo(&buf);
  84                 appendStringInfo(&buf,
  85                                                  "Waiting for custom wait event \"%s\" defined by extension module",
  86                                                  waiteventnames[idx]);
  87
  88                 values[2] = CStringGetTextDatum(buf.data);
  89
  90                 tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
  91         }
  92
  93         /* Likewise for injection points */
  94         waiteventnames = GetWaitEventCustomNames(PG_WAIT_INJECTIONPOINT,
  95                                                                                          &nbwaitevents);
  96
  97         for (int idx = 0; idx < nbwaitevents; idx++)
  98         {
  99                 StringInfoData buf;
 100                 Datum           values[PG_GET_WAIT_EVENTS_COLS] = {0};
 101                 bool            nulls[PG_GET_WAIT_EVENTS_COLS] = {0};
 102
 103
 104                 values[0] = CStringGetTextDatum("InjectionPoint");
 105                 values[1] = CStringGetTextDatum(waiteventnames[idx]);
 106
 107                 initStringInfo(&buf);
 108                 appendStringInfo(&buf,
 109                                                  "Waiting for injection point \"%s\"",
 110                                                  waiteventnames[idx]);
 111
 112                 values[2] = CStringGetTextDatum(buf.data);
 113
 114                 tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 115         }
 116
 117         return (Datum) 0;
 118 }