Specifying Multiple Partitioning Keys in a RANGE Partitioned Table v10

You can often improve performance by specifying multiple key columns for a RANGE partitioned table. If you often select rows using comparison operators (based on a greater-than or less-than value) on a small set of columns, consider using those columns in RANGE partitioning rules.

Specifying Multiple Keys in a Range-Partitioned Table

Range-partitioned table definitions may include multiple columns in the partitioning key. To specify multiple partitioning keys for a range-partitioned table, include the column names in a comma-separated list after the PARTITION BY RANGE clause.

CREATE TABLE sales
(
  dept_no      number,
  part_no      varchar2,
  country      varchar2(20),
  sale_year    number,
  sale_month   number,
  sale_day     number,
  amount       number
)
PARTITION BY RANGE(sale_year, sale_month)
(
  PARTITION q1_2012
    VALUES LESS THAN(2012, 4),
  PARTITION q2_2012
    VALUES LESS THAN(2012, 7),
  PARTITION q3_2012
    VALUES LESS THAN(2012, 10),
  PARTITION q4_2012
    VALUES LESS THAN(2013, 1)
);

If a table is created with multiple partitioning keys, you must specify multiple key values when querying the table to take full advantage of partition pruning.

edb=# EXPLAIN SELECT * FROM sales WHERE sale_year = 2012 AND sale_month = 8;
                                QUERY PLAN
----------------------------------------------------------------------------
 Append  (cost=0.00..14.35 rows=1 width=250)
   ->  Seq Scan on sales_q3_2012  (cost=0.00..14.35 rows=1 width=250)
         Filter: ((sale_year = '2012'::numeric) AND (sale_month = '8'::numeric))
(3 rows)

Since all rows with a value of 8 in the sale_month column and a value of 2012 in the sale_year column will be stored in the q3_2012 partition, Advanced Server searches only that partition.