openGauss每日一练第17天

openGauss逻辑结构-索引管理

1.创建表，在表中创建索引

--创建表testtab01
omm=# create table testtab01(id serial primary key ,testnum serial);
NOTICE:  CREATE TABLE will create implicit sequence "testtab01_id_seq" for serial column "testtab01.id"
NOTICE:  CREATE TABLE will create implicit sequence "testtab01_testnum_seq" for serial column "testtab01.testnum"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "testtab01_pkey" for table "testtab01"
CREATE TABLE

--创建索引
omm=# create index idx_testtab01_testnum on testtab01(testsum);
ERROR:  column "testsum" does not exist
omm=# create index idx_testtab01_testnum on testtab01(testnum);
CREATE INDEX

--查看索引
omm=# \di
                          List of relations
 Schema |         Name          | Type  | Owner |   Table   | Storage 
--------+-----------------------+-------+-------+-----------+---------
 public | idx_testtab01_testnum | index | omm   | testtab01 | 
 public | testtab01_pkey        | index | omm   | testtab01 | 
(2 rows)

2.通过hint使用索引

--创建测试表
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)
);

--插入测试数据
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');

--创建索引
create index customer_idx on  customer(ca_address_sk);

--执行计划
omm=# EXPLAIN SELECT /*+ indexscan(customer customer_idx ) */  * 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

omm=# alter index idx_testtab01_testnum rename to idx_testtab01_testnum01;
ALTER INDEX

4.重建索引

omm=# alter index idx_testtab01_testnum01 rebuild;
REINDEX
omm=# reindex index idx_testtab01_testnum01 ;
REINDEX
omm=# reindex table testtab01;
REINDEX

5.移动索引到其他表空间

--创建测试index
omm=# create tablespace myindex_ts relative location 'tablespace/myindex_ts1';
CREATE TABLESPACE

--修改索引的表空间
omm=# alter index idx_testtab01_testnum01 set tablespace myindex_ts;
ALTER INDEX

--查看索引所在表空间
omm=# select * from pg_indexes where tablename='testtab01';
 schemaname | tablename |        indexname        | tablespace |                                           indexdef                              
              
------------+-----------+-------------------------+------------+---------------------------------------------------------------------------------
--------------
 public     | testtab01 | testtab01_pkey          |            | CREATE UNIQUE INDEX testtab01_pkey ON testtab01 USING btree (id) TABLESPACE pg_d
efault
 public     | testtab01 | idx_testtab01_testnum01 | myindex_ts | CREATE INDEX idx_testtab01_testnum01 ON testtab01 USING btree (testnum) TABLESPA
CE myindex_ts
(2 rows)

--查看索引所在表空间
omm=# select * from pg_indexes where indexname='idx_testtab01_testnum01';
 schemaname | tablename |        indexname        | tablespace |                                           indexdef                              
              
------------+-----------+-------------------------+------------+---------------------------------------------------------------------------------
--------------
 public     | testtab01 | idx_testtab01_testnum01 | myindex_ts | CREATE INDEX idx_testtab01_testnum01 ON testtab01 USING btree (testnum) TABLESPA
CE myindex_ts
(1 row)

6.删除索引

omm=# drop index idx_testtab01_testnum01;
DROP INDEX