Remove pg_class.relhaspkey

It is not used for anything internally, and it cannot be relied on for
external uses, so it can just be removed.  To correct recommended way to
check for a primary key is in pg_index.

Discussion: https://www.postgresql.org/message-id/flat/b1a24c6c-6913-f89c-674e-0704f0ed69db@2ndquadrant.com

4 files changed, 2 insertions, 42 deletions

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index cf36ce4add7..3d80ff9e5bb 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -798,7 +798,6 @@ InsertPgClassTuple(Relation pg_class_desc,
 	values[Anum_pg_class_relnatts - 1] = Int16GetDatum(rd_rel->relnatts);
 	values[Anum_pg_class_relchecks - 1] = Int16GetDatum(rd_rel->relchecks);
 	values[Anum_pg_class_relhasoids - 1] = BoolGetDatum(rd_rel->relhasoids);
-	values[Anum_pg_class_relhaspkey - 1] = BoolGetDatum(rd_rel->relhaspkey);
 	values[Anum_pg_class_relhasrules - 1] = BoolGetDatum(rd_rel->relhasrules);
 	values[Anum_pg_class_relhastriggers - 1] = BoolGetDatum(rd_rel->relhastriggers);
 	values[Anum_pg_class_relrowsecurity - 1] = BoolGetDatum(rd_rel->relrowsecurity);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 431bc319699..9e2dd0e729e 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -125,7 +125,7 @@ static void UpdateIndexRelation(Oid indexoid, Oid heapoid,
 					bool isvalid,
 					bool isready);
 static void index_update_stats(Relation rel,
-				   bool hasindex, bool isprimary,
+				   bool hasindex,
 				   double reltuples);
 static void IndexCheckExclusion(Relation heapRelation,
 					Relation indexRelation,
@@ -1162,7 +1162,6 @@ index_create(Relation heapRelation,
 		 */
 		index_update_stats(heapRelation,
 						   true,
-						   isprimary,
 						   -1.0);
 		/* Make the above update visible */
 		CommandCounterIncrement();
@@ -1365,21 +1364,6 @@ index_constraint_create(Relation heapRelation,
 	}
 
 	/*
-	 * If needed, mark the table as having a primary key.  We assume it can't
-	 * have been so marked already, so no need to clear the flag in the other
-	 * case.
-	 *
-	 * Note: this might better be done by callers.  We do it here to avoid
-	 * exposing index_update_stats() globally, but that wouldn't be necessary
-	 * if relhaspkey went away.
-	 */
-	if (mark_as_primary)
-		index_update_stats(heapRelation,
-						   true,
-						   true,
-						   -1.0);
-
-	/*
 	 * If needed, mark the index as primary and/or deferred in pg_index.
 	 *
 	 * Note: When making an existing index into a constraint, caller must have
@@ -2041,7 +2025,6 @@ FormIndexDatum(IndexInfo *indexInfo,
  * to ensure we can do all the necessary work in just one update.
  *
  * hasindex: set relhasindex to this value
- * isprimary: if true, set relhaspkey true; else no change
  * reltuples: if >= 0, set reltuples to this value; else no change
  *
  * If reltuples >= 0, relpages and relallvisible are also updated (using
@@ -2058,7 +2041,6 @@ FormIndexDatum(IndexInfo *indexInfo,
 static void
 index_update_stats(Relation rel,
 				   bool hasindex,
-				   bool isprimary,
 				   double reltuples)
 {
 	Oid			relid = RelationGetRelid(rel);
@@ -2088,7 +2070,7 @@ index_update_stats(Relation rel,
 	 * It is safe to use a non-transactional update even though our
 	 * transaction could still fail before committing.  Setting relhasindex
 	 * true is safe even if there are no indexes (VACUUM will eventually fix
-	 * it), likewise for relhaspkey.  And of course the new relpages and
+	 * it).  And of course the new relpages and
 	 * reltuples counts are correct regardless.  However, we don't want to
 	 * change relpages (or relallvisible) if the caller isn't providing an
 	 * updated reltuples count, because that would bollix the
@@ -2140,14 +2122,6 @@ index_update_stats(Relation rel,
 		rd_rel->relhasindex = hasindex;
 		dirty = true;
 	}
-	if (isprimary)
-	{
-		if (!rd_rel->relhaspkey)
-		{
-			rd_rel->relhaspkey = true;
-			dirty = true;
-		}
-	}
 
 	if (reltuples >= 0)
 	{
@@ -2356,12 +2330,10 @@ index_build(Relation heapRelation,
 	 */
 	index_update_stats(heapRelation,
 					   true,
-					   isprimary,
 					   stats->heap_tuples);
 
 	index_update_stats(indexRelation,
 					   false,
-					   false,
 					   stats->index_tuples);
 
 	/* Make the updated catalog row versions visible */
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index b50c554c517..18b3966a1f7 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -909,16 +909,6 @@ vac_update_relstats(Relation relation,
 			dirty = true;
 		}
 
-		/*
-		 * If we have discovered that there are no indexes, then there's no
-		 * primary key either.  This could be done more thoroughly...
-		 */
-		if (pgcform->relhaspkey && !hasindex)
-		{
-			pgcform->relhaspkey = false;
-			dirty = true;
-		}
-
 		/* We also clear relhasrules and relhastriggers if needed */
 		if (pgcform->relhasrules && relation->rd_rules == NULL)
 		{
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index f3a9b639a80..679be605f14 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -618,7 +618,6 @@ DefineQueryRewrite(const char *rulename,
 		classForm->relhasindex = false;
 		classForm->relkind = RELKIND_VIEW;
 		classForm->relhasoids = false;
-		classForm->relhaspkey = false;
 		classForm->relfrozenxid = InvalidTransactionId;
 		classForm->relminmxid = InvalidMultiXactId;
 		classForm->relreplident = REPLICA_IDENTITY_NOTHING;