1. EnterpriseDB, Postgres Plus and Dynatune are trademarks of EnterpriseDB Corporation. Other names may be trademarks of their respective owners. © 2011. All rights reserved. PostgreSQL Partitioning Using Inheritance and Check Constraints Presented by Chetan Suttraway November 22, 2011 Chetan.Suttraway @enterprisedb.com

6. Partitioning via Inheritance © 2011 EnterpriseDB. All rights reserved. CREATE OR REPLACE FUNCTION orders_insert() RETURNS TRIGGER AS $$ BEGIN IF (NEW.order_date >= DATE '2011-01-01' AND NEW.order_date < DATE '2012-01-01') THEN INSERT INTO orders_part_2011 VALUES (NEW.*); ELSIF (NEW.order_date < DATE '2011-01-01') THEN INSERT INTO orders_part_2010 VALUES (NEW.*); ELSE RAISE EXCEPTION 'Date out of range. check orders_insert() function!'; END IF; RETURN NULL; END; $$ LANGUAGE plpgsql; CREATE TRIGGER orders_insert_trigger BEFORE INSERT ON orders FOR EACH ROW EXECUTE PROCEDURE orders_insert(); High Maintenance No quoting, NULL issues Fast, No locking for updation of function

7. © 2011 EnterpriseDB. All rights reserved. Partitioning via Inheritance pg=# INSERT INTO orders VALUES(1, 'pune', '2011-08-22'); INSERT 0 0 SELECT * FROM orders; id | address | order_date ----+--------------+--------------------------- 1 | pune | 22-AUG-11 00:00:00 2 | bengaluru | 22-FEB-10 00:00:00 (2 rows) pg=# INSERT INTO orders VALUES(2, 'pune', '2010-02-22'); INSERT 0 0 pg=# UPDATE orders SET address = 'bengaluru' WHERE id = 2; UPDATE 1 SELECT * FROM orders_part_2011; id | address | order_date ----+---------+------------------------ 1 | pune | 22-AUG-11 00:00:00 (1 row) SELECT * FROM orders_part_2010; id | address | order_date ----+-----------+-------------------- 2 | bengaluru | 22-FEB-10 00:00:00 (1 row) SELECT * FROM ONLY orders; id | address | order_date ----+---------+------------ (0 rows)

8. © 2011 EnterpriseDB. All rights reserved. Partitioning via Inheritance EXPLAIN SELECT * FROM orders WHERE order_date = '02-JAN-11'; QUERY PLAN ---------------------------------------------------------------------------------------- Result (cost=0.00..26.01 rows=7 width=40) -> Append (cost=0.00..26.01 rows=7 width=40) -> Seq Scan on orders (cost=0.00..23.75 rows=6 width=44) Filter: (order_date = '02-JAN-11 00:00:00'::timestamp without time zone) -> Seq Scan on orders_part_2011 orders (cost=0.00..2.26 rows=1 width=18) Filter: (order_date = '02-JAN-11 00:00:00'::timestamp without time zone) (6 rows) EXPLAIN SELECT * FROM orders WHERE order_date = '02-JAN-10'; QUERY PLAN ---------------------------------------------------------------------------------------- Result (cost=0.00..24.76 rows=7 width=44) -> Append (cost=0.00..24.76 rows=7 width=44) -> Seq Scan on orders (cost=0.00..23.75 rows=6 width=44) Filter: (order_date = '02-JAN-10 00:00:00'::timestamp without time zone) -> Seq Scan on orders_part_2010 orders (cost=0.00..1.01 rows=1 width=44) Filter: (order_date = '02-JAN-10 00:00:00'::timestamp without time zone) (6 rows

16. © 2011 EnterpriseDB. All rights reserved. Querying Over Partitions...MAX pg=# EXPLAIN SELECT MAX(order_date) FROM orders; QUERY PLAN -------------------------------------------------------------------------------- Result (cost=26.56..26.57 rows=1 width=0) InitPlan 1 (returns $0) -> Limit (cost=26.52..26.56 rows=1 width=8) -> Merge Append (cost=26.52..73.51 rows=1196 width=8) Sort Key: public.orders.order_date -> Sort (cost=26.47..29.21 rows=1094 width=8) Sort Key: public.orders.order_date -> Seq Scan on orders (cost=0.00..21.00 rows=1094 width=8) Filter: (order_date IS NOT NULL) -> Index Scan Backward using orders_part_2011_idx on orders_pa rt_2011 orders (cost=0.00..14.02 rows=101 width=8) Index Cond: (order_date IS NOT NULL) -> Index Scan Backward using orders_part_old_idx on orders_par t_old orders (cost=0.00..8.27 rows=1 width=8) Index Cond: (order_date IS NOT NULL) (13 rows)