Early error out when creating citus local from a temp table (#4592)

src/backend/distributed/commands/citus_add_local_table_to_metadata.c

@@ -362,6 +362,21 @@ ErrorIfUnsupportedCitusLocalTableKind(Oid relationId)
 							   "tables and foreign tables can be added to citus metadata ",
 							   relationName)));
 	}
+
+	if (get_rel_persistence(relationId) == RELPERSISTENCE_TEMP)
+	{
+		/*
+		 * Currently, we use citus local tables only to support foreign keys
+		 * between local tables and reference tables. Citus already doesn't
+		 * support creating reference tables from temp tables.
+		 * So now we are creating a citus local table from a temp table that
+		 * has a foreign key from/to a reference table with persistent storage.
+		 * In that case, we want to give the same error as postgres would do.
+		 */
+		ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("constraints on temporary tables may reference only "
+							   "temporary tables")));
+	}
 }
 
 

src/test/regress/expected/citus_local_tables.out

@@ -50,6 +50,12 @@ SELECT 1 FROM master_add_node('localhost', :master_port, groupId => 0);
 (1 row)
 
 RESET client_min_messages;
+BEGIN;
+  CREATE TEMPORARY TABLE temp_table (a int);
+  -- errors out as we don't support creating citus local table from a temp table
+  SELECT citus_add_local_table_to_metadata('temp_table');
+ERROR:  constraints on temporary tables may reference only temporary tables
+ROLLBACK;
 -- creating citus local table having no data initially would work
 SELECT citus_add_local_table_to_metadata('citus_local_table_1');
  citus_add_local_table_to_metadata

src/test/regress/sql/citus_local_tables.sql

@@ -40,6 +40,12 @@ set client_min_messages to ERROR;
 SELECT 1 FROM master_add_node('localhost', :master_port, groupId => 0);
 RESET client_min_messages;
 
+BEGIN;
+  CREATE TEMPORARY TABLE temp_table (a int);
+  -- errors out as we don't support creating citus local table from a temp table
+  SELECT citus_add_local_table_to_metadata('temp_table');
+ROLLBACK;
+
 -- creating citus local table having no data initially would work
 SELECT citus_add_local_table_to_metadata('citus_local_table_1');