openGauss每日一练第 19 天

opengauss 学习第十九天

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

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

create table products
(
        c1 int,
        c2 CHAR(2)
)
partition by range (c1)
(
        partition products_p0 values less than (50),
        partition products_p1 values less than (100),
        partition products_p2 values less than (150),
        partition products_p3 values less than (200),
        partition products_p4 values less than (300)
);
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insert into products values(generate_series(1, 299));
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2.收集表统计信息

select relname, relpages, reltuples from pg_class where relname = 'products';
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analyze products;
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select relname, relpages, reltuples from pg_class where relname = 'products';
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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

EXPLAIN SELECT * FROM products;
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create index products_c1_index on products(c1);
EXPLAIN SELECT * FROM products  WHERE c1 <100;
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4.更新表数据，并做垃圾收集

update products set c1= c1+ 1 where c1<100;
VACUUM (VERBOSE, ANALYZE) products;
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5.清理数据

drop table products;
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第十九天学习openGauss 收集统计信息、打印执行计划、垃圾收集和checkpoint;

每天进步一点点，期待明天加油！