Revert structural changes to not-null constraints

There are some problems with the new way to handle these constraints
that were detected at the last minute, and require fixes that appear too
invasive to be doing this late in the cycle.  Revert this (again) for
now, we'll try again with these problems fixed.

The following commits are reverted:

    b0e96f311985  Catalog not-null constraints
    9b581c534186  Disallow changing NO INHERIT status of a not-null constraint
    d0ec2ddbe088  Fix not-null constraint test
    ac22a9545ca9  Move privilege check to the right place
    b0f7dd915bca  Check stack depth in new recursive functions
    3af721794272  Update information_schema definition for not-null constraints
    c3709100be73  Fix propagating attnotnull in multiple inheritance
    d9f686a72ee9  Fix restore of not-null constraints with inheritance
    d72d32f52d26  Don't try to assign smart names to constraints
    0cd711271d42  Better handle indirect constraint drops
    13daa33fa5a6  Disallow NO INHERIT not-null constraints on partitioned tables
    d45597f72fe5  Disallow direct change of NO INHERIT of not-null constraints
    21ac38f498b3  Fix inconsistencies in error messages

Discussion: https://postgr.es/m/202405110940.joxlqcx4dogd@alvherre.pgsql

1 files changed, 7 insertions, 35 deletions

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 262c9878dd3..e6072cbdd9e 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -4810,46 +4810,18 @@ RelationGetIndexList(Relation relation)
 		result = lappend_oid(result, index->indexrelid);
 
 		/*
-		 * Non-unique or predicate indexes aren't interesting for either oid
-		 * indexes or replication identity indexes, so don't check them.
-		 * Deferred ones are not useful for replication identity either; but
-		 * we do include them if they are PKs.
+		 * Invalid, non-unique, non-immediate or predicate indexes aren't
+		 * interesting for either oid indexes or replication identity indexes,
+		 * so don't check them.
 		 */
-		if (!index->indisunique ||
+		if (!index->indisvalid || !index->indisunique ||
+			!index->indimmediate ||
 			!heap_attisnull(htup, Anum_pg_index_indpred, NULL))
 			continue;
 
-		/*
-		 * Remember primary key index, if any.  We do this only if the index
-		 * is valid; but if the table is partitioned, then we do it even if
-		 * it's invalid.
-		 *
-		 * The reason for returning invalid primary keys for foreign tables is
-		 * because of pg_dump of NOT NULL constraints, and the fact that PKs
-		 * remain marked invalid until the partitions' PKs are attached to it.
-		 * If we make rd_pkindex invalid, then the attnotnull flag is reset
-		 * after the PK is created, which causes the ALTER INDEX ATTACH
-		 * PARTITION to fail with 'column ... is not marked NOT NULL'.  With
-		 * this, dropconstraint_internal() will believe that the columns must
-		 * not have attnotnull reset, so the PKs-on-partitions can be attached
-		 * correctly, until finally the PK-on-parent is marked valid.
-		 *
-		 * Also, this doesn't harm anything, because rd_pkindex is not a
-		 * "real" index anyway, but a RELKIND_PARTITIONED_INDEX.
-		 */
-		if (index->indisprimary &&
-			(index->indisvalid ||
-			 relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE))
-		{
+		/* remember primary key index if any */
+		if (index->indisprimary)
 			pkeyIndex = index->indexrelid;
-			pkdeferrable = !index->indimmediate;
-		}
-
-		if (!index->indimmediate)
-			continue;
-
-		if (!index->indisvalid)
-			continue;
 
 		/* remember explicitly chosen replica index */
 		if (index->indisreplident)