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 <[email protected]>
Reviewed-by: Nathan Bossart <[email protected]>
Reviewed-by: Robert Treat <[email protected]>
Reviewed-by: Corey Huinker <[email protected]>
Reviewed-by: Greg Sabino Mullane <[email protected]>
Discussion: https://postgr.es/m/flat/CAAKRu_aj-P7YyBz_cPNwztz6ohP%2BvWis%3Diz3YcomkB3NpYA--w%40mail.gmail.com

2 files changed, 11 insertions, 3 deletions

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 956f196fc95..7ef6f0f1cba 100644
--- a/src/backend/catalog/heap.c
+++ b/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)
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f37b990c81d..8e1741c81f5 100644
--- a/src/backend/catalog/index.c
+++ b/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;
+		}
 	}
 
 	/*