import psycopg2 conn = psycopg2.connect("dbname=regression") cursor = conn.cursor() cursor.execute(""" set enable_seqscan to on; set enable_indexscan to off; set enable_hashjoin to off; set enable_mergejoin to off; set enable_material to off; set parallel_setup_cost=0; set parallel_tuple_cost=0; set min_parallel_table_scan_size=0; set max_parallel_workers_per_gather=4; alter table tenk2 set (parallel_workers = 0); """) for i in range(10000): cursor.execute("select count(*) from tenk1, tenk2 where tenk1.hundred > 1 and tenk2.thousand=0") count, = cursor.fetchone() if count != 98000: print "count = %d, after %d tests" % (count, i)