openGauss每日一练第19天 openGauss收集统计信息、打印执行计划、垃圾收集和checkpoint

一.创建表，并用generate_series(1,N)函数对表插入数据

Create schema tpcds;
CREATE TABLE tpcds.customer_address
(
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 tpcds.customer_address values(generate_series(0, 10000));
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二.收集表统计信息

select relname, relpages, reltuples from pg_class where relname = 'customer_address';
analyze VERBOSE tpcds.customer_address;
select relname, relpages, reltuples from pg_class where relname = 'customer_address';
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三.显示简单查询的执行计划；建立索引并显示有索引条件的执行计划
1.显示简单查询的执行计划

SET explain_perf_mode=normal;
EXPLAIN SELECT * FROM tpcds.customer_address;
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2.建立索引并显示有索引条件的执行计划

create index index_ca_address_sk on tpcds.customer_address(ca_address_sk);
EXPLAIN SELECT * FROM tpcds.customer_address WHERE ca_address_sk<100;
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四.更新表数据，并做垃圾收集

update tpcds.customer_address set ca_address_sk = ca_address_sk + 1 where ca_address_sk <100;
VACUUM (VERBOSE, ANALYZE) tpcds.customer_address;
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五.清理数据

drop schema tpcds cascade;
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