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authorMichael Paquier2024-11-22 01:12:26 +0000
committerMichael Paquier2024-11-22 01:12:26 +0000
commitc06e71d1acaf490660ed4ae5c28b3079628746b0 (patch)
tree266b42e6e6936a3ec7cfc18a9e3807ebad4981e5
parent4c4aaa19a6fed39e0eb0247625331c3df34d8211 (diff)
Add write_to_file to PgStat_KindInfo for pgstats kinds
This new field controls if entries of a stats kind should be written or not to the on-disk pgstats file when shutting down an instance. This affects both fixed and variable-numbered kinds. This is useful for custom statistics by itself, and a patch is under discussion to add a new builtin stats kind where the write of the stats is not necessary. All the built-in stats kinds, as well as the two custom stats kinds in the test module injection_points, set this flag to "true" for now, so as stats entries are written to the on-disk pgstats file. Author: Bertrand Drouvot Reviewed-by: Nazir Bilal Yavuz Discussion: https://postgr.es/m/[email protected]
-rw-r--r--src/backend/utils/activity/pgstat.c22
-rw-r--r--src/include/utils/pgstat_internal.h3
-rw-r--r--src/test/modules/injection_points/injection_stats.c1
-rw-r--r--src/test/modules/injection_points/injection_stats_fixed.c1
4 files changed, 26 insertions, 1 deletions
diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c
index ea8c5691e87..6f8d2378266 100644
--- a/src/backend/utils/activity/pgstat.c
+++ b/src/backend/utils/activity/pgstat.c
@@ -12,7 +12,8 @@
* Statistics are loaded from the filesystem during startup (by the startup
* process), unless preceded by a crash, in which case all stats are
* discarded. They are written out by the checkpointer process just before
- * shutting down, except when shutting down in immediate mode.
+ * shutting down (if the stats kind allows it), except when shutting down in
+ * immediate mode.
*
* Fixed-numbered stats are stored in plain (non-dynamic) shared memory.
*
@@ -281,6 +282,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "database",
.fixed_amount = false,
+ .write_to_file = true,
/* so pg_stat_database entries can be seen in all databases */
.accessed_across_databases = true,
@@ -297,6 +299,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "relation",
.fixed_amount = false,
+ .write_to_file = true,
.shared_size = sizeof(PgStatShared_Relation),
.shared_data_off = offsetof(PgStatShared_Relation, stats),
@@ -311,6 +314,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "function",
.fixed_amount = false,
+ .write_to_file = true,
.shared_size = sizeof(PgStatShared_Function),
.shared_data_off = offsetof(PgStatShared_Function, stats),
@@ -324,6 +328,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "replslot",
.fixed_amount = false,
+ .write_to_file = true,
.accessed_across_databases = true,
@@ -340,6 +345,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "subscription",
.fixed_amount = false,
+ .write_to_file = true,
/* so pg_stat_subscription_stats entries can be seen in all databases */
.accessed_across_databases = true,
@@ -359,6 +365,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "archiver",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, archiver),
.shared_ctl_off = offsetof(PgStat_ShmemControl, archiver),
@@ -374,6 +381,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "bgwriter",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, bgwriter),
.shared_ctl_off = offsetof(PgStat_ShmemControl, bgwriter),
@@ -389,6 +397,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "checkpointer",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, checkpointer),
.shared_ctl_off = offsetof(PgStat_ShmemControl, checkpointer),
@@ -404,6 +413,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "io",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, io),
.shared_ctl_off = offsetof(PgStat_ShmemControl, io),
@@ -421,6 +431,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "slru",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, slru),
.shared_ctl_off = offsetof(PgStat_ShmemControl, slru),
@@ -438,6 +449,7 @@ static const PgStat_KindInfo pgstat_kind_builtin_infos[PGSTAT_KIND_BUILTIN_SIZE]
.name = "wal",
.fixed_amount = true,
+ .write_to_file = true,
.snapshot_ctl_off = offsetof(PgStat_Snapshot, wal),
.shared_ctl_off = offsetof(PgStat_ShmemControl, wal),
@@ -1617,6 +1629,10 @@ pgstat_write_statsfile(XLogRecPtr redo)
if (pgstat_is_kind_builtin(kind))
Assert(info->snapshot_ctl_off != 0);
+ /* skip if no need to write to file */
+ if (!info->write_to_file)
+ continue;
+
pgstat_build_snapshot_fixed(kind);
if (pgstat_is_kind_builtin(kind))
ptr = ((char *) &pgStatLocal.snapshot) + info->snapshot_ctl_off;
@@ -1663,6 +1679,10 @@ pgstat_write_statsfile(XLogRecPtr redo)
/* if not dropped the valid-entry refcount should exist */
Assert(pg_atomic_read_u32(&ps->refcount) > 0);
+ /* skip if no need to write to file */
+ if (!kind_info->write_to_file)
+ continue;
+
if (!kind_info->to_serialized_name)
{
/* normal stats entry, identified by PgStat_HashKey */
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 437db06910b..7338bc1e28e 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -213,6 +213,9 @@ typedef struct PgStat_KindInfo
*/
bool accessed_across_databases:1;
+ /* Should stats be written to the on-disk stats file? */
+ bool write_to_file:1;
+
/*
* The size of an entry in the shared stats hash table (pointed to by
* PgStatShared_HashEntry->body). For fixed-numbered statistics, this is
diff --git a/src/test/modules/injection_points/injection_stats.c b/src/test/modules/injection_points/injection_stats.c
index d89d0559134..e16b9db2845 100644
--- a/src/test/modules/injection_points/injection_stats.c
+++ b/src/test/modules/injection_points/injection_stats.c
@@ -39,6 +39,7 @@ static bool injection_stats_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
static const PgStat_KindInfo injection_stats = {
.name = "injection_points",
.fixed_amount = false, /* Bounded by the number of points */
+ .write_to_file = true,
/* Injection points are system-wide */
.accessed_across_databases = true,
diff --git a/src/test/modules/injection_points/injection_stats_fixed.c b/src/test/modules/injection_points/injection_stats_fixed.c
index 2fed178b7a6..c5b0bb8cf04 100644
--- a/src/test/modules/injection_points/injection_stats_fixed.c
+++ b/src/test/modules/injection_points/injection_stats_fixed.c
@@ -50,6 +50,7 @@ static void injection_stats_fixed_snapshot_cb(void);
static const PgStat_KindInfo injection_stats_fixed = {
.name = "injection_points_fixed",
.fixed_amount = true,
+ .write_to_file = true,
.shared_size = sizeof(PgStat_StatInjFixedEntry),
.shared_data_off = offsetof(PgStatShared_InjectionPointFixed, stats),