-- -- MULTI_LIMIT_CLAUSE -- -- Display debug messages on limit clause push down. SET client_min_messages TO DEBUG1; -- Check that we can correctly handle the Limit clause in distributed queries. -- Note that we don't have the limit optimization enabled for these queries, and -- will end up fetching all rows to the master database. SELECT count(*) count_quantity, l_quantity FROM lineitem WHERE l_quantity < 32.0 GROUP BY l_quantity ORDER BY count_quantity ASC, l_quantity ASC; count_quantity | l_quantity ----------------+------------ 219 | 13.00 222 | 29.00 227 | 3.00 229 | 18.00 229 | 31.00 230 | 14.00 230 | 16.00 230 | 17.00 230 | 26.00 232 | 7.00 234 | 10.00 235 | 15.00 236 | 25.00 237 | 2.00 241 | 12.00 242 | 6.00 242 | 22.00 243 | 1.00 243 | 19.00 244 | 4.00 246 | 20.00 249 | 24.00 249 | 27.00 250 | 8.00 250 | 11.00 254 | 5.00 255 | 21.00 258 | 9.00 261 | 23.00 264 | 30.00 273 | 28.00 (31 rows) SELECT count(*) count_quantity, l_quantity FROM lineitem WHERE l_quantity < 32.0 GROUP BY l_quantity ORDER BY count_quantity DESC, l_quantity DESC; count_quantity | l_quantity ----------------+------------ 273 | 28.00 264 | 30.00 261 | 23.00 258 | 9.00 255 | 21.00 254 | 5.00 250 | 11.00 250 | 8.00 249 | 27.00 249 | 24.00 246 | 20.00 244 | 4.00 243 | 19.00 243 | 1.00 242 | 22.00 242 | 6.00 241 | 12.00 237 | 2.00 236 | 25.00 235 | 15.00 234 | 10.00 232 | 7.00 230 | 26.00 230 | 17.00 230 | 16.00 230 | 14.00 229 | 31.00 229 | 18.00 227 | 3.00 222 | 29.00 219 | 13.00 (31 rows) SELECT count(*) count_quantity, l_quantity FROM lineitem WHERE l_quantity < 32.0 GROUP BY l_quantity ORDER BY count_quantity ASC, l_quantity ASC LIMIT 5; count_quantity | l_quantity ----------------+------------ 219 | 13.00 222 | 29.00 227 | 3.00 229 | 18.00 229 | 31.00 (5 rows) SELECT count(*) count_quantity, l_quantity FROM lineitem WHERE l_quantity < 32.0 GROUP BY l_quantity ORDER BY count_quantity ASC, l_quantity ASC LIMIT 10; count_quantity | l_quantity ----------------+------------ 219 | 13.00 222 | 29.00 227 | 3.00 229 | 18.00 229 | 31.00 230 | 14.00 230 | 16.00 230 | 17.00 230 | 26.00 232 | 7.00 (10 rows) SELECT count(*) count_quantity, l_quantity FROM lineitem WHERE l_quantity < 32.0 GROUP BY l_quantity ORDER BY count_quantity DESC, l_quantity DESC LIMIT 10; count_quantity | l_quantity ----------------+------------ 273 | 28.00 264 | 30.00 261 | 23.00 258 | 9.00 255 | 21.00 254 | 5.00 250 | 11.00 250 | 8.00 249 | 27.00 249 | 24.00 (10 rows) -- Check that we can handle limits for simple sort clauses. We order by columns -- in the first two tests, and then by a simple expression in the last test. SELECT min(l_orderkey) FROM lineitem; min ----- 1 (1 row) SELECT l_orderkey FROM lineitem ORDER BY l_orderkey ASC LIMIT 1; DEBUG: push down of limit count: 1 l_orderkey ------------ 1 (1 row) SELECT max(l_orderkey) FROM lineitem; max ------- 14947 (1 row) SELECT l_orderkey FROM lineitem ORDER BY l_orderkey DESC LIMIT 1; DEBUG: push down of limit count: 1 l_orderkey ------------ 14947 (1 row) SELECT * FROM lineitem ORDER BY l_orderkey DESC, l_linenumber DESC LIMIT 3; DEBUG: push down of limit count: 3 l_orderkey | l_partkey | l_suppkey | l_linenumber | l_quantity | l_extendedprice | l_discount | l_tax | l_returnflag | l_linestatus | l_shipdate | l_commitdate | l_receiptdate | l_shipinstruct | l_shipmode | l_comment ------------+-----------+-----------+--------------+------------+-----------------+------------+-------+--------------+--------------+------------+--------------+---------------+---------------------------+------------+--------------------------------- 14947 | 107098 | 7099 | 2 | 29.00 | 32047.61 | 0.04 | 0.06 | N | O | 11-08-1995 | 08-30-1995 | 12-03-1995 | TAKE BACK RETURN | FOB | inal sentiments t 14947 | 31184 | 3688 | 1 | 14.00 | 15612.52 | 0.09 | 0.02 | N | O | 11-05-1995 | 09-25-1995 | 11-27-1995 | TAKE BACK RETURN | RAIL | bout the even, iro 14946 | 79479 | 4494 | 2 | 37.00 | 53963.39 | 0.01 | 0.01 | N | O | 11-27-1996 | 02-01-1997 | 11-29-1996 | COLLECT COD | AIR | sleep furiously after the furio (3 rows) SELECT max(extract(epoch from l_shipdate)) FROM lineitem; max ----------- 912124800 (1 row) SELECT * FROM lineitem ORDER BY extract(epoch from l_shipdate) DESC, l_orderkey DESC LIMIT 3; DEBUG: push down of limit count: 3 l_orderkey | l_partkey | l_suppkey | l_linenumber | l_quantity | l_extendedprice | l_discount | l_tax | l_returnflag | l_linestatus | l_shipdate | l_commitdate | l_receiptdate | l_shipinstruct | l_shipmode | l_comment ------------+-----------+-----------+--------------+------------+-----------------+------------+-------+--------------+--------------+------------+--------------+---------------+---------------------------+------------+-------------------------------------- 4678 | 57388 | 9894 | 1 | 35.00 | 47088.30 | 0.04 | 0.08 | N | O | 11-27-1998 | 10-02-1998 | 12-17-1998 | TAKE BACK RETURN | AIR | he accounts. fluffily bold sheaves b 12384 | 84161 | 1686 | 5 | 6.00 | 6870.96 | 0.04 | 0.00 | N | O | 11-26-1998 | 10-04-1998 | 12-08-1998 | COLLECT COD | RAIL | ep blithely. blithely ironic r 1124 | 92298 | 4808 | 3 | 35.00 | 45160.15 | 0.10 | 0.05 | N | O | 11-25-1998 | 10-08-1998 | 12-25-1998 | TAKE BACK RETURN | AIR | ut the slyly bold pinto beans; fi (3 rows) -- Exercise the scenario where order by clauses don't have any aggregates, and -- that we can push down the limit as a result. Check that when this happens, we -- also sort on all group by clauses behind the covers. SELECT l_quantity, l_discount, avg(l_partkey) FROM lineitem GROUP BY l_quantity, l_discount ORDER BY l_quantity LIMIT 1; DEBUG: push down of limit count: 1 l_quantity | l_discount | avg ------------+------------+-------------------- 1.00 | 0.00 | 99167.304347826087 (1 row) -- Results from the previous query should match this query's results. SELECT l_quantity, l_discount, avg(l_partkey) FROM lineitem GROUP BY l_quantity, l_discount ORDER BY l_quantity, l_discount LIMIT 1; DEBUG: push down of limit count: 1 l_quantity | l_discount | avg ------------+------------+-------------------- 1.00 | 0.00 | 99167.304347826087 (1 row) SET client_min_messages TO NOTICE;