Add relallfrozen to pg_class

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

src/backend/access/heap/vacuumlazy.c

@@ -623,7 +623,8 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
 				minmulti_updated;
 	BlockNumber orig_rel_pages,
 				new_rel_pages,
-				new_rel_allvisible;
+				new_rel_allvisible,
+				new_rel_allfrozen;
 	PGRUsage	ru0;
 	TimestampTz starttime = 0;
 	PgStat_Counter startreadtime = 0,
@@ -898,10 +899,18 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
 	 * pg_class.relpages to
 	 */
 	new_rel_pages = vacrel->rel_pages;	/* After possible rel truncation */
-	visibilitymap_count(rel, &new_rel_allvisible, NULL);
+	visibilitymap_count(rel, &new_rel_allvisible, &new_rel_allfrozen);
 	if (new_rel_allvisible > new_rel_pages)
 		new_rel_allvisible = new_rel_pages;
 
+	/*
+	 * An all-frozen block _must_ be all-visible. As such, clamp the count of
+	 * all-frozen blocks to the count of all-visible blocks. This matches the
+	 * clamping of relallvisible above.
+	 */
+	if (new_rel_allfrozen > new_rel_allvisible)
+		new_rel_allfrozen = new_rel_allvisible;
+
 	/*
 	 * Now actually update rel's pg_class entry.
 	 *
@@ -910,7 +919,8 @@ heap_vacuum_rel(Relation rel, VacuumParams *params,
 	 * scan every page that isn't skipped using the visibility map.
 	 */
 	vac_update_relstats(rel, new_rel_pages, vacrel->new_live_tuples,
-						new_rel_allvisible, vacrel->nindexes > 0,
+						new_rel_allvisible, new_rel_allfrozen,
+						vacrel->nindexes > 0,
 						vacrel->NewRelfrozenXid, vacrel->NewRelminMxid,
 						&frozenxid_updated, &minmulti_updated, false);
 
@@ -3720,7 +3730,7 @@ update_relstats_all_indexes(LVRelState *vacrel)
 		vac_update_relstats(indrel,
 							istat->num_pages,
 							istat->num_index_tuples,
-							0,
+							0, 0,
 							false,
 							InvalidTransactionId,
 							InvalidMultiXactId,

src/backend/catalog/heap.c

@@ -924,6 +924,7 @@ InsertPgClassTuple(Relation pg_class_desc,
 	values[Anum_pg_class_relpages - 1] = Int32GetDatum(rd_rel->relpages);
 	values[Anum_pg_class_reltuples - 1] = Float4GetDatum(rd_rel->reltuples);
 	values[Anum_pg_class_relallvisible - 1] = Int32GetDatum(rd_rel->relallvisible);
+	values[Anum_pg_class_relallfrozen - 1] = Int32GetDatum(rd_rel->relallfrozen);
 	values[Anum_pg_class_reltoastrelid - 1] = ObjectIdGetDatum(rd_rel->reltoastrelid);
 	values[Anum_pg_class_relhasindex - 1] = BoolGetDatum(rd_rel->relhasindex);
 	values[Anum_pg_class_relisshared - 1] = BoolGetDatum(rd_rel->relisshared);
@@ -994,6 +995,7 @@ AddNewRelationTuple(Relation pg_class_desc,
 	new_rel_reltup->relpages = 0;
 	new_rel_reltup->reltuples = -1;
 	new_rel_reltup->relallvisible = 0;
+	new_rel_reltup->relallfrozen = 0;
 
 	/* Sequences always have a known size */
 	if (relkind == RELKIND_SEQUENCE)

src/backend/catalog/index.c

@@ -2793,8 +2793,8 @@ FormIndexDatum(IndexInfo *indexInfo,
  * hasindex: set relhasindex to this value
  * reltuples: if >= 0, set reltuples to this value; else no change
  *
- * If reltuples >= 0, relpages and relallvisible are also updated (using
- * RelationGetNumberOfBlocks() and visibilitymap_count()).
+ * If reltuples >= 0, relpages, relallvisible, and relallfrozen are also
+ * updated (using RelationGetNumberOfBlocks() and visibilitymap_count()).
  *
  * NOTE: an important side-effect of this operation is that an SI invalidation
  * message is sent out to all backends --- including me --- causing relcache
@@ -2812,6 +2812,7 @@ index_update_stats(Relation rel,
 	bool		update_stats;
 	BlockNumber relpages = 0;	/* keep compiler quiet */
 	BlockNumber relallvisible = 0;
+	BlockNumber relallfrozen = 0;
 	Oid			relid = RelationGetRelid(rel);
 	Relation	pg_class;
 	ScanKeyData key[1];
@@ -2851,7 +2852,7 @@ index_update_stats(Relation rel,
 		relpages = RelationGetNumberOfBlocks(rel);
 
 		if (rel->rd_rel->relkind != RELKIND_INDEX)
-			visibilitymap_count(rel, &relallvisible, NULL);
+			visibilitymap_count(rel, &relallvisible, &relallfrozen);
 	}
 
 	/*
@@ -2924,6 +2925,11 @@ index_update_stats(Relation rel,
 			rd_rel->relallvisible = (int32) relallvisible;
 			dirty = true;
 		}
+		if (rd_rel->relallfrozen != (int32) relallfrozen)
+		{
+			rd_rel->relallfrozen = (int32) relallfrozen;
+			dirty = true;
+		}
 	}
 
 	/*

src/backend/commands/analyze.c

@@ -630,12 +630,11 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 	 */
 	if (!inh)
 	{
-		BlockNumber relallvisible;
+		BlockNumber relallvisible = 0;
+		BlockNumber relallfrozen = 0;
 
 		if (RELKIND_HAS_STORAGE(onerel->rd_rel->relkind))
-			visibilitymap_count(onerel, &relallvisible, NULL);
-		else
-			relallvisible = 0;
+			visibilitymap_count(onerel, &relallvisible, &relallfrozen);
 
 		/*
 		 * Update pg_class for table relation.  CCI first, in case acquirefunc
@@ -646,6 +645,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 							relpages,
 							totalrows,
 							relallvisible,
+							relallfrozen,
 							hasindex,
 							InvalidTransactionId,
 							InvalidMultiXactId,
@@ -662,7 +662,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			vac_update_relstats(Irel[ind],
 								RelationGetNumberOfBlocks(Irel[ind]),
 								totalindexrows,
-								0,
+								0, 0,
 								false,
 								InvalidTransactionId,
 								InvalidMultiXactId,
@@ -678,7 +678,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		 */
 		CommandCounterIncrement();
 		vac_update_relstats(onerel, -1, totalrows,
-							0, hasindex, InvalidTransactionId,
+							0, 0, hasindex, InvalidTransactionId,
 							InvalidMultiXactId,
 							NULL, NULL,
 							in_outer_xact);

src/backend/commands/cluster.c

@@ -1226,6 +1226,7 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 		int32		swap_pages;
 		float4		swap_tuples;
 		int32		swap_allvisible;
+		int32		swap_allfrozen;
 
 		swap_pages = relform1->relpages;
 		relform1->relpages = relform2->relpages;
@@ -1238,6 +1239,10 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
 		swap_allvisible = relform1->relallvisible;
 		relform1->relallvisible = relform2->relallvisible;
 		relform2->relallvisible = swap_allvisible;
+
+		swap_allfrozen = relform1->relallfrozen;
+		relform1->relallfrozen = relform2->relallfrozen;
+		relform2->relallfrozen = swap_allfrozen;
 	}
 
 	/*

src/backend/commands/vacuum.c

@@ -1427,6 +1427,7 @@ void
 vac_update_relstats(Relation relation,
 					BlockNumber num_pages, double num_tuples,
 					BlockNumber num_all_visible_pages,
+					BlockNumber num_all_frozen_pages,
 					bool hasindex, TransactionId frozenxid,
 					MultiXactId minmulti,
 					bool *frozenxid_updated, bool *minmulti_updated,
@@ -1476,6 +1477,11 @@ vac_update_relstats(Relation relation,
 		pgcform->relallvisible = (int32) num_all_visible_pages;
 		dirty = true;
 	}
+	if (pgcform->relallfrozen != (int32) num_all_frozen_pages)
+	{
+		pgcform->relallfrozen = (int32) num_all_frozen_pages;
+		dirty = true;
+	}
 
 	/* Apply DDL updates, but not inside an outer transaction (see above) */
 

src/backend/statistics/relation_stats.c

@@ -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();

src/backend/utils/cache/relcache.c

@@ -1928,6 +1928,7 @@ formrdesc(const char *relationName, Oid relationReltype,
 	relation->rd_rel->relpages = 0;
 	relation->rd_rel->reltuples = -1;
 	relation->rd_rel->relallvisible = 0;
+	relation->rd_rel->relallfrozen = 0;
 	relation->rd_rel->relkind = RELKIND_RELATION;
 	relation->rd_rel->relnatts = (int16) natts;
 
@@ -3885,6 +3886,7 @@ RelationSetNewRelfilenumber(Relation relation, char persistence)
 			classform->relpages = 0;	/* it's empty until further notice */
 			classform->reltuples = -1;
 			classform->relallvisible = 0;
+			classform->relallfrozen = 0;
 		}
 		classform->relfrozenxid = freezeXid;
 		classform->relminmxid = minmulti;