openGauss分区表支持两种索引:全局(global)索引和本地(local)索引。 分区表创建索引不支持concurrently语法,默认索引是全局索引,创建本地索引需要指定local。 创建主键约束和唯一约束必须要包含分区字段,创建本地唯一索引也必须要包含分区字段,但是创建全局唯一索引没有这个限制。 postgres=# create index concurrently on part_index_test(col2,col1,col3); ERROR: cannot create concurrent partitioned indexes 本文主要阐述添加或删除分区对索引的影响。 数据库版本:openGauss 1.1.0 一.建表语句范围分区中的间隔语法可以自动追加分区表,这里以间隔分区表为例: create table part_index_test( partid varchar(32) not null, col1 varchar(2) not null, col2 date not null, col3 varchar(8) not null )partition by range(col2) interval('1 day') ( partition part1 values less than ('20210331'), partition part2 values less than ('20210401') );
二.测试数据间隔分区是以1天为单位,所以新增一天的数据,会自动增加一个以sys_p开头的自增分区: insert into part_index_test select generate_series(1,1000),'1','20210401',generate_series(1,1000); insert into part_index_test select generate_series(1,1000),'1','20210402',generate_series(1,1000); insert into part_index_test select generate_series(1,1000),'1','20210403',generate_series(1,1000); insert into part_index_test select generate_series(1,1000),'1','20210404',generate_series(1,1000); insert into part_index_test select generate_series(1,1000),'1','20210405',generate_series(1,1000); insert into part_index_test select generate_series(1,1000),'1','20210406',generate_series(1,1000); 三.删除分区语法
select relname,parttype,parentid,boundaries from pg_partition;
alter table part_index_test DROP PARTITIONpartition_name;
alter table part_index_test DROP PARTITION partition_name update global index; 四.索引使用explain select * from part_index_test where col2=$1 and partid=$2; 五.测试结果
总结:1、添加/删除分区不影响本地索引使用。 2、添加分区不影响全局索引使用,默认删除分区方式,全局索引失效,需要对全局索引重建;update global index方式删除分区,不影响全局索引使用。 一.分区表准备
create table part_range_lessthan_int( id serial primary key, col1 varchar(16)) partition by range(id) ( partition p1 values less than(1000), partition p2 values less than(2000), partition p3 values less than(3000), partition p4 values less than(maxvalue) );
create unique index on part_range_lessthan_int(col1);
insert into part_range_lessthan_int select generate_series(1,5000),'tuple'||generate_series(1,5000);
select now();alter table part_range_lessthan_int drop partition p1;
select now();alter table part_range_lessthan_int drop partition p1 update global index;
analyze;select now();explain select * from part_range_lessthan_int where col1='tuple2500'; 二.默认删除分区语法 |
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