学习目标

学习openGauss收集统计信息、打印执行计划、垃圾收集和checkpoint

课后作业

1.创建分区表，并用generate_series(1,N)函数对表插入数据

create schema eason;
create table eason.students
(
        id int,
        name CHAR(20)
)
partition by range (id)
(
        partition students_p0 values less than (50),
        partition students_p1 values less than (100),
        partition students_p2 values less than (150),
	partition students_p3 values less than (200),
        partition students_p4 values less than (10001)
);


insert into eason.students values(generate_series(10, 10000));

2.收集表统计信息

select relname, relpages, reltuples from pg_class where relname = 'students';
analyze VERBOSE eason.students;
select relname, relpages, reltuples from pg_class where relname = 'students';

3.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

SET explain_perf_mode=normal;
EXPLAIN SELECT * FROM eason.students  WHERE id<100;
create index students_idx on eason.students(id);
EXPLAIN SELECT * FROM eason.students WHERE id<100;

4.更新表数据，并做垃圾收集

update eason.students set id = id + 1 where id < 100;
VACUUM (VERBOSE, ANALYZE) eason.students;

5.清理数据

CHECKPOINT;
drop table eason.students;
drop schema eason;