postgresql10 一些常用的查询

1. 查询索引的有效性

   select d.tablename,a.relname,(case c.indisvalid when true then '有效' else '无效' end) isvalid ,c.indkey from pg_class a ,pg_namespace b ,pg_index c ,pg_indexes d  where a.relkind = 'i' and a.relname=b.oid and b.nspname='public' and a.oid = c.indexrelid and d.indexname=a.relname order by d.tablename;

2. 表查询

   select * from pg_table where schemaname = 'xxx';

3. 查询索引或者表的大小

   select pg_size_pretty(pg_relaion_size('test'));

4. 统计表的行数

   select a.relname,a.reltuples::int from pg_class a ,pg_namespace b where a.relnamespace=b.oid and b.nspname='public' and a.relkind='r' order by a.relname;