1 创建索引

zyfdb=> create table test(id serial primary key,testnum serial);
NOTICE:  CREATE TABLE will create implicit sequence "test_id_seq" for serial column "test.id"
NOTICE:  CREATE TABLE will create implicit sequence "test_testnum_seq" for serial column "test.testnum"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "test_pkey" for table "test"
CREATE TABLE
zyfdb=>
zyfdb=> create index idx_test_testnum on test(testnum);
CREATE INDEX


zyfdb=>  查看索引
zyfdb=> \di
                      List of relations
 Schema |       Name       | Type  | Owner | Table | Storage
--------+------------------+-------+-------+-------+---------
 public | idx_test_testnum | index | user5 | test  |
 public | test_pkey        | index | user5 | test  |
(2 rows)

2 通过hint使用索引

CREATE TABLE customer
(
ca_address_sk integer NOT NULL ,
ca_address_id character(16),
ca_street_number character(10) ,
ca_street_name character varying(60) ,
ca_street_type character(15) ,
ca_suite_number character(10) ,
ca_city character varying(60) ,
ca_county character varying(30) ,
ca_state character(2) ,
ca_zip character(10) ,
ca_country character varying(20) ,
ca_gmt_offset numeric(5,2) ,
ca_location_type character(20)
);
insert into customer values
(1, 'AAAAAAAABAAAAAAA', '18', 'Jackson', 'Parkway', 'Suite 280', 'Fairfield', 'Maricopa County', 'AZ', '86192' ,'United States', -7.00, 'condo'),
(2, 'AAAAAAAACAAAAAAA', '362', 'Washington 6th', 'RD', 'Suite 80', 'Fairview', 'Taos County', 'NM', '85709', 'United States', -7.00, 'condo'),
(3, 'AAAAAAAADAAAAAAA', '585', 'Dogwood Washington', 'Circle', 'Suite Q', 'Pleasant Valley', 'York County', 'PA', '12477', 'United States', -5.00, 'single family');


EXPLAIN SELECT  * FROM customer WHERE ca_address_sk<100;

zyfdb=> EXPLAIN SELECT  * FROM customer WHERE ca_address_sk<100;
                         QUERY PLAN
------------------------------------------------------------
 Seq Scan on customer  (cost=0.00..11.25 rows=33 width=788)
   Filter: (ca_address_sk < 100)
(2 rows)


create index customer_idx on  customer(ca_address_sk);


EXPLAIN SELECT /*+ indexscan(customer customer_idx ) */ 
 * FROM customer WHERE ca_address_sk<100;

zyfdb=> EXPLAIN SELECT /*+ indexscan(customer customer_idx ) */
zyfdb->  * FROM customer WHERE ca_address_sk<100;
                                  QUERY PLAN
-------------------------------------------------------------------------------
 [Bypass]
 Index Scan using customer_idx on customer  (cost=0.00..8.27 rows=1 width=788)
   Index Cond: (ca_address_sk < 100)
(3 rows)

3 rename索引

zyfdb=>
zyfdb=> ALTER INDEX idx_test_testnum RENAME TO idx_test_testnum_new;
ALTER INDEX
zyfdb=>
zyfdb=> \di
                         List of relations
 Schema |         Name         | Type  | Owner |  Table   | Storage
--------+----------------------+-------+-------+----------+---------
 public | customer_idx         | index | user5 | customer |
 public | idx_test_testnum_new | index | user5 | test     |
 public | test_pkey            | index | user5 | test     |
(3 rows)

4 重建索引

--重建一个单独索引
ALTER INDEX  idx_test_testnum_new REBUILD;

REINDEX INDEX  idx_test_testnum_new;
--重建所有索引
reindex table test;

5 移动索引到其他表空间

--查看索引所在的表空间
 select * from pg_indexes where tablename = 'test';

zyfdb=>  select schemaname ,tablename ,indexname , tablespace  from pg_indexes where tablename = 'test';
 schemaname | tablename |      indexname       | tablespace
------------+-----------+----------------------+------------
 public     | test      | test_pkey            |
 public     | test      | idx_test_testnum_new |
(2 rows)

--将索引idx_test_testnum_new移动到表空间myindex_ts：
  ALTER INDEX idx_test_testnum_new SET TABLESPACE enmtbs;


--或
 select schemaname ,tablename ,indexname , tablespace 
   from pg_indexes 
  where indexname = 'idx_test_testnum_new';
 schemaname | tablename |      indexname       | tablespace
------------+-----------+----------------------+------------
 public     | test      | idx_test_testnum_new | enmtbs
(1 row)

6 删除索引

zyfdb=> \di
                         List of relations
 Schema |         Name         | Type  | Owner |  Table   | Storage
--------+----------------------+-------+-------+----------+---------
 public | customer_idx         | index | user5 | customer |
 public | idx_test_testnum_new | index | user5 | test     |
 public | test_pkey            | index | user5 | test     |
(3 rows)

zyfdb=> drop index idx_test_testnum_new;
DROP INDEX
zyfdb=> \di
                     List of relations
 Schema |     Name     | Type  | Owner |  Table   | Storage
--------+--------------+-------+-------+----------+---------
 public | customer_idx | index | user5 | customer |
 public | test_pkey    | index | user5 | test     |
(2 rows)