Enhance columnar_relation_storageid to handle temp tables in PG18+

src/backend/columnar/columnar_metadata.c

@@ -2024,6 +2024,26 @@ Datum
 columnar_relation_storageid(PG_FUNCTION_ARGS)
 {
 	Oid relationId = PG_GETARG_OID(0);
+
+#if PG_VERSION_NUM >= PG_VERSION_18
+    /*
+     * PG18+: avoid relation_open() on other sessions' temp tables.
+     * Return NULL so callers/views just skip them (function is STRICT).
+     */
+    HeapTuple   classtup = SearchSysCache1(RELOID, ObjectIdGetDatum(relationId));
+    if (!HeapTupleIsValid(classtup))
+        PG_RETURN_NULL();
+
+    Form_pg_class cls = (Form_pg_class) GETSTRUCT(classtup);
+    if (cls->relpersistence == RELPERSISTENCE_TEMP &&
+        isOtherTempNamespace(cls->relnamespace))
+    {
+        ReleaseSysCache(classtup);
+        PG_RETURN_NULL();
+    }
+    ReleaseSysCache(classtup);
+#endif
+
 	Relation relation = relation_open(relationId, AccessShareLock);
 
 	if (!object_ownercheck(RelationRelationId, relationId, GetUserId()))

src/test/regress/expected/columnar_create.out

@@ -214,8 +214,8 @@ SELECT COUNT(*) FROM columnar_temp WHERE i < 5;
      4
 (1 row)
 
-SELECT COALESCE(columnar_test_helpers.get_storage_id_if_visible('columnar_temp'::regclass), 0)
-       AS columnar_temp_storage_id \gset
+SELECT columnar.get_storage_id(oid) AS columnar_temp_storage_id
+FROM pg_class WHERE relname='columnar_temp' \gset
 BEGIN;
   DROP TABLE columnar_temp;
   -- show that we drop stripes properly

src/test/regress/expected/columnar_recursive.out

@@ -11,19 +11,10 @@ $$ LANGUAGE SQL;
 INSERT INTO t2 SELECT i, f(i) FROM generate_series(1, 5) i;
 -- there are no subtransactions, so above statement should batch
 -- INSERTs inside the UDF and create on stripe per table.
-WITH rels(rel) AS (
-  VALUES ('t1'::regclass), ('t2'::regclass)
-),
-sids AS (
-  SELECT rel, columnar.get_storage_id(rel) AS sid
-  FROM rels
-)
-SELECT c.relname, COUNT(*) AS count
-FROM columnar_internal.stripe st
-JOIN sids s ON st.storage_id = s.sid
-JOIN pg_catalog.pg_class c ON c.oid = s.rel
-GROUP BY c.relname
-ORDER BY c.relname;
+SELECT relname, count(*) FROM columnar.stripe a, pg_class b
+WHERE columnar.get_storage_id(b.oid)=a.storage_id AND relname IN ('t1', 't2')
+GROUP BY relname
+ORDER BY relname;
  relname | count
 ---------------------------------------------------------------------
  t1      |     1

src/test/regress/expected/columnar_test_helpers.out

@@ -146,15 +146,3 @@ BEGIN
     RETURN NEXT;
   END LOOP;
 END; $$ language plpgsql;
-CREATE OR REPLACE FUNCTION get_storage_id_if_visible(rel regclass)
-RETURNS bigint
-LANGUAGE sql STABLE AS $$
-  SELECT CASE
-           WHEN c.relpersistence = 't'
-                AND c.relnamespace <> pg_catalog.pg_my_temp_schema()
-             THEN NULL  -- other session’s temp → don’t touch
-           ELSE columnar.get_storage_id(c.oid)
-         END
-  FROM pg_catalog.pg_class c
-  WHERE c.oid = $1::oid
-$$;

src/test/regress/sql/columnar_create.sql

@@ -174,8 +174,8 @@ INSERT INTO columnar_temp SELECT i FROM generate_series(1,5) i;
 -- test basic select
 SELECT COUNT(*) FROM columnar_temp WHERE i < 5;
 
-SELECT COALESCE(columnar_test_helpers.get_storage_id_if_visible('columnar_temp'::regclass), 0)
-       AS columnar_temp_storage_id \gset
+SELECT columnar.get_storage_id(oid) AS columnar_temp_storage_id
+FROM pg_class WHERE relname='columnar_temp' \gset
 
 BEGIN;
   DROP TABLE columnar_temp;

src/test/regress/sql/columnar_recursive.sql

@@ -15,20 +15,10 @@ INSERT INTO t2 SELECT i, f(i) FROM generate_series(1, 5) i;
 
 -- there are no subtransactions, so above statement should batch
 -- INSERTs inside the UDF and create on stripe per table.
-WITH rels(rel) AS (
-  VALUES ('t1'::regclass), ('t2'::regclass)
-),
-sids AS (
-  SELECT rel, columnar.get_storage_id(rel) AS sid
-  FROM rels
-)
-SELECT c.relname, COUNT(*) AS count
-FROM columnar_internal.stripe st
-JOIN sids s ON st.storage_id = s.sid
-JOIN pg_catalog.pg_class c ON c.oid = s.rel
-GROUP BY c.relname
-ORDER BY c.relname;
-
+SELECT relname, count(*) FROM columnar.stripe a, pg_class b
+WHERE columnar.get_storage_id(b.oid)=a.storage_id AND relname IN ('t1', 't2')
+GROUP BY relname
+ORDER BY relname;
 
 SELECT * FROM t1 ORDER BY a;
 SELECT * FROM t2 ORDER BY a;

src/test/regress/sql/columnar_test_helpers.sql

@@ -158,16 +158,3 @@ BEGIN
     RETURN NEXT;
   END LOOP;
 END; $$ language plpgsql;
-
-CREATE OR REPLACE FUNCTION get_storage_id_if_visible(rel regclass)
-RETURNS bigint
-LANGUAGE sql STABLE AS $$
-  SELECT CASE
-           WHEN c.relpersistence = 't'
-                AND c.relnamespace <> pg_catalog.pg_my_temp_schema()
-             THEN NULL  -- other session’s temp → don’t touch
-           ELSE columnar.get_storage_id(c.oid)
-         END
-  FROM pg_catalog.pg_class c
-  WHERE c.oid = $1::oid
-$$;