创建索引的语句如下：
pgdb=# create index supplier_fk1 on supplier(s_nationkey);CREATE INDEX时间: 241.663 mspgdb=# create index customer_fk1 on customer(c_nationkey);CREATE INDEX时间: 4671.995 mspgdb=# create index partsupp_fk1 on partsupp(ps_suppkey);CREATE INDEX时间: 20420.121 mspgdb=# pgdb=# create index partsupp_fk2 on partsupp(ps_partkey);CREATE INDEX时间: 14487.640 mspgdb=# create index orders_fk1 on orders(o_custkey);CREATE INDEX时间: 38558.701 mspgdb=# drop index orders_custkey;DROP INDEX时间: 98.454 mspgdb=# create index lineitem_fk1 on lineitem(l_orderkey);CREATE INDEX时间: 103888.944 mspgdb=# create index lineitem_fk2 on lineitem(l_partkey,l_suppkey);CREATE INDEX时间: 187944.419 mspgdb=# \di List of relations Schema | Name | Type | Owner | Table --------+---------------+-------+----------+---------- public | customer_fk1 | index | postgres | customer public | customer_pkey | index | postgres | customer public | lineitem_fk1 | index | postgres | lineitem public | lineitem_fk2 | index | postgres | lineitem public | lineitem_pkey | index | postgres | lineitem public | nation_pkey | index | postgres | nation public | orders_fk1 | index | postgres | orders public | orders_pkey | index | postgres | orders public | part_pkey | index | postgres | part public | partsupp_fk1 | index | postgres | partsupp public | partsupp_fk2 | index | postgres | partsupp public | partsupp_pkey | index | postgres | partsupp public | region_pkey | index | postgres | region public | supplier_fk1 | index | postgres | supplier public | supplier_pkey | index | postgres | supplier(15 rows)可以用9.0版新引入的pg_relation_size函数获得某个表的空间占用，代替了以往版本的pg_relation_size,后者也依然可以使用。
select pg_table_size('customer'); pg_table_size --------------- 296615936(1 row)pgdb=# SELECT nspname || '.' || relname AS "relation",pgdb-# pg_size_pretty(pg_relation_size(C.oid)) AS "size"pgdb-# FROM pg_class Cpgdb-# LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)pgdb-# WHERE nspname NOT IN ('pg_catalog', 'information_schema')pgdb-# ORDER BY pg_relation_size(C.oid) DESCpgdb-# ; relation | size -------------------------------+------------ public.lineitem | 9257 MB public.orders | 2093 MB public.partsupp | 1385 MB public.lineitem_fk2 | 1285 MB public.lineitem_fk1 | 1285 MB public.lineitem_pkey | 1285 MB public.part | 325 MB public.orders_fk1 | 321 MB public.orders_pkey | 321 MB public.customer | 283 MB public.partsupp_fk1 | 171 MB public.partsupp_pkey | 171 MB public.partsupp_fk2 | 171 MB public.part_pkey | 43 MB public.customer_fk1 | 32 MB public.customer_pkey | 32 MB public.supplier | 18 MB public.supplier_fk1 | 2208 kB public.supplier_pkey | 2208 kB pg_toast.pg_toast_2618 | 208 kB pg_toast.pg_toast_2619 | 80 kB pg_toast.pg_toast_2618_index | 16 kB public.nation_pkey | 16 kB public.region_pkey | 16 kB pg_toast.pg_toast_2619_index | 16 kB利用前面第一步产生的查询脚本，执行测试的命令行如下,查询结果输出到不同的log文件，以便于比较,分别在创建索引前后执行，注意在更改表存储和索引类型后，更新统计信息。
