Get rid of pg_class.reltoastidxid.

Treat TOAST index just the same as normal one and get the OID
of TOAST index from pg_index but not pg_class.reltoastidxid.
This change allows us to handle multiple TOAST indexes, and
which is required infrastructure for upcoming
REINDEX CONCURRENTLY feature.

Patch by Michael Paquier, reviewed by Andres Freund and me.

3 files changed, 9 insertions, 25 deletions

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 4fd42ed1af5..f1cdef9e130 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -781,7 +781,6 @@ InsertPgClassTuple(Relation pg_class_desc,
 	values[Anum_pg_class_reltuples - 1] = Float4GetDatum(rd_rel->reltuples);
 	values[Anum_pg_class_relallvisible - 1] = Int32GetDatum(rd_rel->relallvisible);
 	values[Anum_pg_class_reltoastrelid - 1] = ObjectIdGetDatum(rd_rel->reltoastrelid);
-	values[Anum_pg_class_reltoastidxid - 1] = ObjectIdGetDatum(rd_rel->reltoastidxid);
 	values[Anum_pg_class_relhasindex - 1] = BoolGetDatum(rd_rel->relhasindex);
 	values[Anum_pg_class_relisshared - 1] = BoolGetDatum(rd_rel->relisshared);
 	values[Anum_pg_class_relpersistence - 1] = CharGetDatum(rd_rel->relpersistence);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ca0c672c381..8525cb9ec83 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -103,7 +103,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 					bool isvalid);
 static void index_update_stats(Relation rel,
 				   bool hasindex, bool isprimary,
-				   Oid reltoastidxid, double reltuples);
+				   double reltuples);
 static void IndexCheckExclusion(Relation heapRelation,
 					Relation indexRelation,
 					IndexInfo *indexInfo);
@@ -1072,7 +1072,6 @@ index_create(Relation heapRelation,
 		index_update_stats(heapRelation,
 						   true,
 						   isprimary,
-						   InvalidOid,
 						   -1.0);
 		/* Make the above update visible */
 		CommandCounterIncrement();
@@ -1254,7 +1253,6 @@ index_constraint_create(Relation heapRelation,
 		index_update_stats(heapRelation,
 						   true,
 						   true,
-						   InvalidOid,
 						   -1.0);
 
 	/*
@@ -1764,8 +1762,6 @@ FormIndexDatum(IndexInfo *indexInfo,
  *
  * hasindex: set relhasindex to this value
  * isprimary: if true, set relhaspkey true; else no change
- * reltoastidxid: if not InvalidOid, set reltoastidxid to this value;
- *		else no change
  * reltuples: if >= 0, set reltuples to this value; else no change
  *
  * If reltuples >= 0, relpages and relallvisible are also updated (using
@@ -1781,8 +1777,9 @@ FormIndexDatum(IndexInfo *indexInfo,
  */
 static void
 index_update_stats(Relation rel,
-				   bool hasindex, bool isprimary,
-				   Oid reltoastidxid, double reltuples)
+				   bool hasindex,
+				   bool isprimary,
+				   double reltuples)
 {
 	Oid			relid = RelationGetRelid(rel);
 	Relation	pg_class;
@@ -1876,15 +1873,6 @@ index_update_stats(Relation rel,
 			dirty = true;
 		}
 	}
-	if (OidIsValid(reltoastidxid))
-	{
-		Assert(rd_rel->relkind == RELKIND_TOASTVALUE);
-		if (rd_rel->reltoastidxid != reltoastidxid)
-		{
-			rd_rel->reltoastidxid = reltoastidxid;
-			dirty = true;
-		}
-	}
 
 	if (reltuples >= 0)
 	{
@@ -2072,14 +2060,11 @@ index_build(Relation heapRelation,
 	index_update_stats(heapRelation,
 					   true,
 					   isprimary,
-					   (heapRelation->rd_rel->relkind == RELKIND_TOASTVALUE) ?
-					   RelationGetRelid(indexRelation) : InvalidOid,
 					   stats->heap_tuples);
 
 	index_update_stats(indexRelation,
 					   false,
 					   false,
-					   InvalidOid,
 					   stats->index_tuples);
 
 	/* Make the updated catalog row versions visible */
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 81d7c4fec8c..d3086f43dd6 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -473,16 +473,16 @@ CREATE VIEW pg_statio_all_tables AS
             pg_stat_get_blocks_fetched(T.oid) -
                     pg_stat_get_blocks_hit(T.oid) AS toast_blks_read,
             pg_stat_get_blocks_hit(T.oid) AS toast_blks_hit,
-            pg_stat_get_blocks_fetched(X.oid) -
-                    pg_stat_get_blocks_hit(X.oid) AS tidx_blks_read,
-            pg_stat_get_blocks_hit(X.oid) AS tidx_blks_hit
+            sum(pg_stat_get_blocks_fetched(X.indexrelid) -
+                    pg_stat_get_blocks_hit(X.indexrelid))::bigint AS tidx_blks_read,
+            sum(pg_stat_get_blocks_hit(X.indexrelid))::bigint AS tidx_blks_hit
     FROM pg_class C LEFT JOIN
             pg_index I ON C.oid = I.indrelid LEFT JOIN
             pg_class T ON C.reltoastrelid = T.oid LEFT JOIN
-            pg_class X ON T.reltoastidxid = X.oid
+            pg_index X ON T.oid = X.indrelid
             LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
     WHERE C.relkind IN ('r', 't', 'm')
-    GROUP BY C.oid, N.nspname, C.relname, T.oid, X.oid;
+    GROUP BY C.oid, N.nspname, C.relname, T.oid, X.indrelid;
 
 CREATE VIEW pg_statio_sys_tables AS
     SELECT * FROM pg_statio_all_tables