Line data    Source code

       1             : /*--------------------------------------------------------------------------
       2             :  *
       3             :  * injection_stats.c
       4             :  *      Code for statistics of injection points.
       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/test/modules/injection_points/injection_stats.c
      11             :  *
      12             :  * -------------------------------------------------------------------------
      13             :  */
      14             : 
      15             : #include "postgres.h"
      16             : 
      17             : #include "fmgr.h"
      18             : 
      19             : #include "common/hashfn.h"
      20             : #include "injection_stats.h"
      21             : #include "pgstat.h"
      22             : #include "utils/builtins.h"
      23             : #include "utils/pgstat_internal.h"
      24             : 
      25             : /* Structures for statistics of injection points */
      26             : typedef struct PgStat_StatInjEntry
      27             : {
      28             :     PgStat_Counter numcalls;    /* number of times point has been run */
      29             : } PgStat_StatInjEntry;
      30             : 
      31             : typedef struct PgStatShared_InjectionPoint
      32             : {
      33             :     PgStatShared_Common header;
      34             :     PgStat_StatInjEntry stats;
      35             : } PgStatShared_InjectionPoint;
      36             : 
      37             : static bool injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
      38             : 
      39             : static const PgStat_KindInfo injection_stats = {
      40             :     .name = "injection_points",
      41             :     .fixed_amount = false,      /* Bounded by the number of points */
      42             :     .write_to_file = true,
      43             :     .track_entry_count = true,
      44             : 
      45             :     /* Injection points are system-wide */
      46             :     .accessed_across_databases = true,
      47             : 
      48             :     .shared_size = sizeof(PgStatShared_InjectionPoint),
      49             :     .shared_data_off = offsetof(PgStatShared_InjectionPoint, stats),
      50             :     .shared_data_len = sizeof(((PgStatShared_InjectionPoint *) 0)->stats),
      51             :     .pending_size = sizeof(PgStat_StatInjEntry),
      52             :     .flush_pending_cb = injection_stats_flush_cb,
      53             : };
      54             : 
      55             : /*
      56             :  * Compute stats entry idx from point name with an 8-byte hash.
      57             :  */
      58             : #define PGSTAT_INJ_IDX(name) hash_bytes_extended((const unsigned char *) name, strlen(name), 0)
      59             : 
      60             : /*
      61             :  * Kind ID reserved for statistics of injection points.
      62             :  */
      63             : #define PGSTAT_KIND_INJECTION   25
      64             : 
      65             : /* Track if stats are loaded */
      66             : static bool inj_stats_loaded = false;
      67             : 
      68             : /*
      69             :  * Callback for stats handling
      70             :  */
      71             : static bool
      72          14 : injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
      73             : {
      74             :     PgStat_StatInjEntry *localent;
      75             :     PgStatShared_InjectionPoint *shfuncent;
      76             : 
      77          14 :     localent = (PgStat_StatInjEntry *) entry_ref->pending;
      78          14 :     shfuncent = (PgStatShared_InjectionPoint *) entry_ref->shared_stats;
      79             : 
      80          14 :     if (!pgstat_lock_entry(entry_ref, nowait))
      81           0 :         return false;
      82             : 
      83          14 :     shfuncent->stats.numcalls += localent->numcalls;
      84             : 
      85          14 :     pgstat_unlock_entry(entry_ref);
      86             : 
      87          14 :     return true;
      88             : }
      89             : 
      90             : /*
      91             :  * Support function for the SQL-callable pgstat* functions.  Returns
      92             :  * a pointer to the injection point statistics struct.
      93             :  */
      94             : static PgStat_StatInjEntry *
      95           8 : pgstat_fetch_stat_injentry(const char *name)
      96             : {
      97           8 :     PgStat_StatInjEntry *entry = NULL;
      98             : 
      99           8 :     if (!inj_stats_loaded || !inj_stats_enabled)
     100           0 :         return NULL;
     101             : 
     102             :     /* Compile the lookup key as a hash of the point name */
     103           8 :     entry = (PgStat_StatInjEntry *) pgstat_fetch_entry(PGSTAT_KIND_INJECTION,
     104             :                                                        InvalidOid,
     105           8 :                                                        PGSTAT_INJ_IDX(name));
     106           8 :     return entry;
     107             : }
     108             : 
     109             : /*
     110             :  * Workhorse to do the registration work, called in _PG_init().
     111             :  */
     112             : void
     113          10 : pgstat_register_inj(void)
     114             : {
     115          10 :     pgstat_register_kind(PGSTAT_KIND_INJECTION, &injection_stats);
     116             : 
     117             :     /* mark stats as loaded */
     118          10 :     inj_stats_loaded = true;
     119          10 : }
     120             : 
     121             : /*
     122             :  * Report injection point creation.
     123             :  */
     124             : void
     125         120 : pgstat_create_inj(const char *name)
     126             : {
     127             :     PgStat_EntryRef *entry_ref;
     128             :     PgStatShared_InjectionPoint *shstatent;
     129             : 
     130             :     /* leave if disabled */
     131         120 :     if (!inj_stats_loaded || !inj_stats_enabled)
     132         116 :         return;
     133             : 
     134           4 :     entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_INJECTION, InvalidOid,
     135           4 :                                           PGSTAT_INJ_IDX(name), NULL);
     136             : 
     137           4 :     shstatent = (PgStatShared_InjectionPoint *) entry_ref->shared_stats;
     138             : 
     139             :     /* initialize shared memory data */
     140           4 :     memset(&shstatent->stats, 0, sizeof(shstatent->stats));
     141             : }
     142             : 
     143             : /*
     144             :  * Report injection point drop.
     145             :  */
     146             : void
     147         250 : pgstat_drop_inj(const char *name)
     148             : {
     149             :     /* leave if disabled */
     150         250 :     if (!inj_stats_loaded || !inj_stats_enabled)
     151         250 :         return;
     152             : 
     153           0 :     if (!pgstat_drop_entry(PGSTAT_KIND_INJECTION, InvalidOid,
     154           0 :                            PGSTAT_INJ_IDX(name)))
     155           0 :         pgstat_request_entry_refs_gc();
     156             : }
     157             : 
     158             : /*
     159             :  * Report statistics for injection point.
     160             :  *
     161             :  * This is simple because the set of stats to report currently is simple:
     162             :  * track the number of times a point has been run.
     163             :  */
     164             : void
     165         182 : pgstat_report_inj(const char *name)
     166             : {
     167             :     PgStat_EntryRef *entry_ref;
     168             :     PgStat_StatInjEntry *pending;
     169             : 
     170             :     /* leave if disabled */
     171         182 :     if (!inj_stats_loaded || !inj_stats_enabled)
     172         172 :         return;
     173             : 
     174          10 :     entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_INJECTION, InvalidOid,
     175          10 :                                           PGSTAT_INJ_IDX(name), NULL);
     176             : 
     177          10 :     pending = (PgStat_StatInjEntry *) entry_ref->pending;
     178             : 
     179             :     /* Update the injection point pending statistics */
     180          10 :     pending->numcalls++;
     181             : }
     182             : 
     183             : /*
     184             :  * SQL function returning the number of times an injection point
     185             :  * has been called.
     186             :  */
     187          70 : PG_FUNCTION_INFO_V1(injection_points_stats_numcalls);
     188             : Datum
     189           8 : injection_points_stats_numcalls(PG_FUNCTION_ARGS)
     190             : {
     191           8 :     char       *name = text_to_cstring(PG_GETARG_TEXT_PP(0));
     192           8 :     PgStat_StatInjEntry *entry = pgstat_fetch_stat_injentry(name);
     193             : 
     194           8 :     if (entry == NULL)
     195           4 :         PG_RETURN_NULL();
     196             : 
     197           4 :     PG_RETURN_INT64(entry->numcalls);
     198             : }
     199             : 
     200             : /*
     201             :  * SQL function returning the number of entries allocated for injection
     202             :  * points in the shared hashtable of pgstats.
     203             :  */
     204          68 : PG_FUNCTION_INFO_V1(injection_points_stats_count);
     205             : Datum
     206           6 : injection_points_stats_count(PG_FUNCTION_ARGS)
     207             : {
     208           6 :     PG_RETURN_INT64(pgstat_get_entry_count(PGSTAT_KIND_INJECTION));
     209             : }
     210             : 
     211             : /* Only used by injection_points_stats_drop() */
     212             : static bool
     213          66 : match_inj_entries(PgStatShared_HashEntry *entry, Datum match_data)
     214             : {
     215          66 :     return entry->key.kind == PGSTAT_KIND_INJECTION;
     216             : }
     217             : 
     218             : /*
     219             :  * SQL function that drops all injection point statistics.
     220             :  */
     221          64 : PG_FUNCTION_INFO_V1(injection_points_stats_drop);
     222             : Datum
     223           2 : injection_points_stats_drop(PG_FUNCTION_ARGS)
     224             : {
     225           2 :     pgstat_drop_matching_entries(match_inj_entries, 0);
     226             : 
     227           2 :     PG_RETURN_VOID();
     228             : }