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Add relallfrozen to pg_class

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Add relallfrozen, an estimate of the number of pages marked all-frozen
in the visibility map.

pg_class already has relallvisible, an estimate of the number of pages
in the relation marked all-visible in the visibility map. This is used
primarily for planning.

relallfrozen, together with relallvisible, is useful for estimating the
outstanding number of all-visible but not all-frozen pages in the
relation for the purposes of scheduling manual VACUUMs and tuning vacuum
freeze parameters.

A future commit will use relallfrozen to trigger more frequent vacuums
on insert-focused workloads with significant volume of frozen data.

Bump catalog version

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Reviewed-by: Greg Sabino Mullane <htamfids@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_aj-P7YyBz_cPNwztz6ohP%2BvWis%3Diz3YcomkB3NpYA--w%40mail.gmail.com
This commit is contained in:
Melanie Plageman
2025-03-03 11:18:05 -05:00
parent 8492feb98f
commit 99f8f3fbbc
14 changed files with 190 additions and 70 deletions
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29
src/backend/statistics/relation_stats.c
View File

@@ -36,6 +36,7 @@ enum relation_stats_argnum
RELPAGES_ARG,
RELTUPLES_ARG,
RELALLVISIBLE_ARG,
RELALLFROZEN_ARG,
NUM_RELATION_STATS_ARGS
};
@@ -45,6 +46,7 @@ static struct StatsArgInfo relarginfo[] =
[RELPAGES_ARG] = {"relpages", INT4OID},
[RELTUPLES_ARG] = {"reltuples", FLOAT4OID},
[RELALLVISIBLE_ARG] = {"relallvisible", INT4OID},
[RELALLFROZEN_ARG] = {"relallfrozen", INT4OID},
[NUM_RELATION_STATS_ARGS] = {0}
};
@@ -65,11 +67,13 @@ relation_statistics_update(FunctionCallInfo fcinfo)
bool update_reltuples = false;
BlockNumber relallvisible = 0;
bool update_relallvisible = false;
BlockNumber relallfrozen = 0;
bool update_relallfrozen = false;
HeapTuple ctup;
Form_pg_class pgcform;
int replaces[3] = {0};
Datum values[3] = {0};
bool nulls[3] = {0};
int replaces[4] = {0};
Datum values[4] = {0};
bool nulls[4] = {0};
int nreplaces = 0;
if (!PG_ARGISNULL(RELPAGES_ARG))
@@ -98,6 +102,12 @@ relation_statistics_update(FunctionCallInfo fcinfo)
update_relallvisible = true;
}
if (!PG_ARGISNULL(RELALLFROZEN_ARG))
{
relallfrozen = PG_GETARG_UINT32(RELALLFROZEN_ARG);
update_relallfrozen = true;
}
stats_check_required_arg(fcinfo, relarginfo, RELATION_ARG);
reloid = PG_GETARG_OID(RELATION_ARG);
@@ -148,6 +158,13 @@ relation_statistics_update(FunctionCallInfo fcinfo)
nreplaces++;
}
if (update_relallfrozen && relallfrozen != pgcform->relallfrozen)
{
replaces[nreplaces] = Anum_pg_class_relallfrozen;
values[nreplaces] = UInt32GetDatum(relallfrozen);
nreplaces++;
}
if (nreplaces > 0)
{
TupleDesc tupdesc = RelationGetDescr(crel);
@@ -176,9 +193,9 @@ relation_statistics_update(FunctionCallInfo fcinfo)
Datum
pg_clear_relation_stats(PG_FUNCTION_ARGS)
{
LOCAL_FCINFO(newfcinfo, 4);
LOCAL_FCINFO(newfcinfo, 5);
InitFunctionCallInfoData(*newfcinfo, NULL, 4, InvalidOid, NULL, NULL);
InitFunctionCallInfoData(*newfcinfo, NULL, 5, InvalidOid, NULL, NULL);
newfcinfo->args[0].value = PG_GETARG_OID(0);
newfcinfo->args[0].isnull = PG_ARGISNULL(0);
@@ -188,6 +205,8 @@ pg_clear_relation_stats(PG_FUNCTION_ARGS)
newfcinfo->args[2].isnull = false;
newfcinfo->args[3].value = UInt32GetDatum(0);
newfcinfo->args[3].isnull = false;
newfcinfo->args[4].value = UInt32GetDatum(0);
newfcinfo->args[4].isnull = false;
relation_statistics_update(newfcinfo);
PG_RETURN_VOID();