* pgStatPending list. Pending statistics updates are flushed out by
* pgstat_report_stat().
*
+ * It is possible for external modules to define custom statistics kinds,
+ * that can use the same properties as any built-in stats kinds. Each custom
+ * stats kind needs to assign a unique ID to ensure that it does not overlap
+ * with other extensions. In order to reserve a unique stats kind ID, refer
+ * to https://wiki.postgresql.org/wiki/CustomCumulativeStats.
+ *
* The behavior of different kinds of statistics is determined by the kind's
- * entry in pgstat_kind_infos, see PgStat_KindInfo for details.
+ * entry in pgstat_kind_builtin_infos for all the built-in statistics kinds
+ * defined, and pgstat_kind_custom_infos for custom kinds registered at
+ * startup by pgstat_register_kind(). See PgStat_KindInfo for details.
*
* The consistency of read accesses to statistics can be configured using the
* stats_fetch_consistency GUC (see config.sgml and monitoring.sgml for the
static void pgstat_write_statsfile(XLogRecPtr redo);
static void pgstat_read_statsfile(XLogRecPtr redo);
+static void pgstat_init_snapshot_fixed(void);
+
static void pgstat_reset_after_failure(void);
static bool pgstat_flush_pending_entries(bool nowait);
/*
- * The different kinds of statistics.
+ * The different kinds of built-in statistics.
*
* If reasonably possible, handling specific to one kind of stats should go
* through this abstraction, rather than making more of pgstat.c aware.
* seem to be a great way of doing that, given the split across multiple
* files.
*/
-static const PgStat_KindInfo pgstat_kind_infos[PGSTAT_NUM_KINDS] = {
+static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE] = {
/* stats kinds for variable-numbered objects */
},
};
+/*
+ * Information about custom statistics kinds.
+ *
+ * These are saved in a different array than the built-in kinds to save
+ * in clarity with the initializations.
+ *
+ * Indexed by PGSTAT_KIND_CUSTOM_MIN, of size PGSTAT_KIND_CUSTOM_SIZE.
+ */
+static const PgStat_KindInfo **pgstat_kind_custom_infos = NULL;
/* ------------------------------------------------------------
* Functions managing the state of the stats system for all backends.
pgstat_init_wal();
+ pgstat_init_snapshot_fixed();
+
/* Set up a process-exit hook to clean up */
before_shmem_exit(pgstat_shutdown_hook, 0);
memset(&pgStatLocal.snapshot.fixed_valid, 0,
sizeof(pgStatLocal.snapshot.fixed_valid));
+ memset(&pgStatLocal.snapshot.custom_valid, 0,
+ sizeof(pgStatLocal.snapshot.custom_valid));
pgStatLocal.snapshot.stats = NULL;
pgStatLocal.snapshot.mode = PGSTAT_FETCH_CONSISTENCY_NONE;
else
pgstat_build_snapshot_fixed(kind);
- Assert(pgStatLocal.snapshot.fixed_valid[kind]);
+ if (pgstat_is_kind_builtin(kind))
+ Assert(pgStatLocal.snapshot.fixed_valid[kind]);
+ else if (pgstat_is_kind_custom(kind))
+ Assert(pgStatLocal.snapshot.custom_valid[kind - PGSTAT_KIND_CUSTOM_MIN]);
+}
+
+static void
+pgstat_init_snapshot_fixed(void)
+{
+ /*
+ * Initialize fixed-numbered statistics data in snapshots, only for custom
+ * stats kinds.
+ */
+ for (PgStat_Kind kind = PGSTAT_KIND_CUSTOM_MIN; kind <= PGSTAT_KIND_CUSTOM_MAX; kind++)
+ {
+ const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind);
+
+ if (!kind_info || !kind_info->fixed_amount)
+ continue;
+
+ pgStatLocal.snapshot.custom_data[kind - PGSTAT_KIND_CUSTOM_MIN] =
+ MemoryContextAlloc(TopMemoryContext, kind_info->shared_data_len);
+ }
}
static void
/*
* Build snapshot of all fixed-numbered stats.
*/
- for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++)
+ for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++)
{
const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind);
+ if (!kind_info)
+ continue;
if (!kind_info->fixed_amount)
{
Assert(kind_info->snapshot_cb == NULL);
pgstat_build_snapshot_fixed(PgStat_Kind kind)
{
const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind);
+ int idx;
+ bool *valid;
+
+ /* Position in fixed_valid or custom_valid */
+ if (pgstat_is_kind_builtin(kind))
+ {
+ idx = kind;
+ valid = pgStatLocal.snapshot.fixed_valid;
+ }
+ else
+ {
+ idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+ valid = pgStatLocal.snapshot.custom_valid;
+ }
Assert(kind_info->fixed_amount);
Assert(kind_info->snapshot_cb != NULL);
if (pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_NONE)
{
/* rebuild every time */
- pgStatLocal.snapshot.fixed_valid[kind] = false;
+ valid[idx] = false;
}
- else if (pgStatLocal.snapshot.fixed_valid[kind])
+ else if (valid[idx])
{
/* in snapshot mode we shouldn't get called again */
Assert(pgstat_fetch_consistency == PGSTAT_FETCH_CONSISTENCY_CACHE);
return;
}
- Assert(!pgStatLocal.snapshot.fixed_valid[kind]);
+ Assert(!valid[idx]);
kind_info->snapshot_cb();
- Assert(!pgStatLocal.snapshot.fixed_valid[kind]);
- pgStatLocal.snapshot.fixed_valid[kind] = true;
+ Assert(!valid[idx]);
+ valid[idx] = true;
}
PgStat_Kind
pgstat_get_kind_from_str(char *kind_str)
{
- for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++)
+ for (PgStat_Kind kind = PGSTAT_KIND_BUILTIN_MIN; kind <= PGSTAT_KIND_BUILTIN_MAX; kind++)
{
- if (pg_strcasecmp(kind_str, pgstat_kind_infos[kind].name) == 0)
+ if (pg_strcasecmp(kind_str, pgstat_kind_builtin_infos[kind].name) == 0)
return kind;
}
+ /* Check the custom set of cumulative stats */
+ if (pgstat_kind_custom_infos)
+ {
+ for (PgStat_Kind kind = PGSTAT_KIND_CUSTOM_MIN; kind <= PGSTAT_KIND_CUSTOM_MAX; kind++)
+ {
+ uint32 idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ if (pgstat_kind_custom_infos[idx] &&
+ pg_strcasecmp(kind_str, pgstat_kind_custom_infos[idx]->name) == 0)
+ return kind;
+ }
+ }
+
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid statistics kind: \"%s\"", kind_str)));
- return PGSTAT_KIND_DATABASE; /* avoid compiler warnings */
+ return PGSTAT_KIND_INVALID; /* avoid compiler warnings */
}
static inline bool
pgstat_is_kind_valid(PgStat_Kind kind)
{
- return kind >= PGSTAT_KIND_FIRST_VALID && kind <= PGSTAT_KIND_LAST;
+ return pgstat_is_kind_builtin(kind) || pgstat_is_kind_custom(kind);
}
const PgStat_KindInfo *
pgstat_get_kind_info(PgStat_Kind kind)
{
- Assert(pgstat_is_kind_valid(kind));
+ if (pgstat_is_kind_builtin(kind))
+ return &pgstat_kind_builtin_infos[kind];
+
+ if (pgstat_is_kind_custom(kind))
+ {
+ uint32 idx = kind - PGSTAT_KIND_CUSTOM_MIN;
- return &pgstat_kind_infos[kind];
+ if (pgstat_kind_custom_infos == NULL ||
+ pgstat_kind_custom_infos[idx] == NULL)
+ return NULL;
+ return pgstat_kind_custom_infos[idx];
+ }
+
+ return NULL;
+}
+
+/*
+ * Register a new stats kind.
+ *
+ * PgStat_Kinds must be globally unique across all extensions. Refer
+ * to https://wiki.postgresql.org/wiki/CustomCumulativeStats to reserve a
+ * unique ID for your extension, to avoid conflicts with other extension
+ * developers. During development, use PGSTAT_KIND_EXPERIMENTAL to avoid
+ * needlessly reserving a new ID.
+ */
+void
+pgstat_register_kind(PgStat_Kind kind, const PgStat_KindInfo *kind_info)
+{
+ uint32 idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ if (kind_info->name == NULL || strlen(kind_info->name) == 0)
+ ereport(ERROR,
+ (errmsg("custom cumulative statistics name is invalid"),
+ errhint("Provide a non-empty name for the custom cumulative statistics.")));
+
+ if (!pgstat_is_kind_custom(kind))
+ ereport(ERROR, (errmsg("custom cumulative statistics ID %u is out of range", kind),
+ errhint("Provide a custom cumulative statistics ID between %u and %u.",
+ PGSTAT_KIND_CUSTOM_MIN, PGSTAT_KIND_CUSTOM_MAX)));
+
+ if (!process_shared_preload_libraries_in_progress)
+ ereport(ERROR,
+ (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind),
+ errdetail("Custom cumulative statistics must be registered while initializing modules in \"shared_preload_libraries\".")));
+
+ /*
+ * Check some data for fixed-numbered stats.
+ */
+ if (kind_info->fixed_amount)
+ {
+ if (kind_info->shared_size == 0)
+ ereport(ERROR,
+ (errmsg("custom cumulative statistics property is invalid"),
+ errhint("Custom cumulative statistics require a shared memory size for fixed-numbered objects.")));
+ }
+
+ /*
+ * If pgstat_kind_custom_infos is not available yet, allocate it.
+ */
+ if (pgstat_kind_custom_infos == NULL)
+ {
+ pgstat_kind_custom_infos = (const PgStat_KindInfo **)
+ MemoryContextAllocZero(TopMemoryContext,
+ sizeof(PgStat_KindInfo *) * PGSTAT_KIND_CUSTOM_SIZE);
+ }
+
+ if (pgstat_kind_custom_infos[idx] != NULL &&
+ pgstat_kind_custom_infos[idx]->name != NULL)
+ ereport(ERROR,
+ (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind),
+ errdetail("Custom cumulative statistics \"%s\" already registered with the same ID.",
+ pgstat_kind_custom_infos[idx]->name)));
+
+ /* check for existing custom stats with the same name */
+ for (PgStat_Kind existing_kind = PGSTAT_KIND_CUSTOM_MIN; existing_kind <= PGSTAT_KIND_CUSTOM_MAX; existing_kind++)
+ {
+ uint32 existing_idx = existing_kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ if (pgstat_kind_custom_infos[existing_idx] == NULL)
+ continue;
+ if (!pg_strcasecmp(pgstat_kind_custom_infos[existing_idx]->name, kind_info->name))
+ ereport(ERROR,
+ (errmsg("failed to register custom cumulative statistics \"%s\" with ID %u", kind_info->name, kind),
+ errdetail("Existing cumulative statistics with ID %u has the same name.", existing_kind)));
+ }
+
+ /* Register it */
+ pgstat_kind_custom_infos[idx] = kind_info;
+ ereport(LOG,
+ (errmsg("registered custom cumulative statistics \"%s\" with ID %u",
+ kind_info->name, kind)));
}
/*
write_chunk_s(fpout, &redo);
/* Write various stats structs for fixed number of objects */
- for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++)
+ for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++)
{
char *ptr;
const PgStat_KindInfo *info = pgstat_get_kind_info(kind);
- if (!info->fixed_amount)
+ if (!info || !info->fixed_amount)
continue;
- Assert(info->snapshot_ctl_off != 0);
+ if (pgstat_is_kind_builtin(kind))
+ Assert(info->snapshot_ctl_off != 0);
pgstat_build_snapshot_fixed(kind);
- ptr = ((char *) &pgStatLocal.snapshot) + info->snapshot_ctl_off;
+ if (pgstat_is_kind_builtin(kind))
+ ptr = ((char *) &pgStatLocal.snapshot) + info->snapshot_ctl_off;
+ else
+ ptr = pgStatLocal.snapshot.custom_data[kind - PGSTAT_KIND_CUSTOM_MIN];
fputc(PGSTAT_FILE_ENTRY_FIXED, fpout);
write_chunk_s(fpout, &kind);
if (ps->dropped)
continue;
+ /*
+ * This discards data related to custom stats kinds that are unknown
+ * to this process.
+ */
+ if (!pgstat_is_kind_valid(ps->key.kind))
+ {
+ elog(WARNING, "found unknown stats entry %u/%u/%u",
+ ps->key.kind, ps->key.dboid, ps->key.objoid);
+ continue;
+ }
+
shstats = (PgStatShared_Common *) dsa_get_address(pgStatLocal.dsa, ps->body);
kind_info = pgstat_get_kind_info(ps->key.kind);
}
/* Load back stats into shared memory */
- ptr = ((char *) shmem) + info->shared_ctl_off +
- info->shared_data_off;
+ if (pgstat_is_kind_builtin(kind))
+ ptr = ((char *) shmem) + info->shared_ctl_off +
+ info->shared_data_off;
+ else
+ {
+ int idx = kind - PGSTAT_KIND_CUSTOM_MIN;
+
+ ptr = ((char *) shmem->custom_data[idx]) +
+ info->shared_data_off;
+ }
if (!read_chunk(fpin, ptr, info->shared_data_len))
{
TimestampTz ts = GetCurrentTimestamp();
/* reset fixed-numbered stats */
- for (PgStat_Kind kind = PGSTAT_KIND_FIRST_VALID; kind <= PGSTAT_KIND_LAST; kind++)
+ for (PgStat_Kind kind = PGSTAT_KIND_MIN; kind <= PGSTAT_KIND_MAX; kind++)
{
const PgStat_KindInfo *kind_info = pgstat_get_kind_info(kind);
- if (!kind_info->fixed_amount)
+ if (!kind_info || !kind_info->fixed_amount)
continue;
kind_info->reset_all_cb(ts);
projects / postgresql.git / commitdiff