PostgreSQL实用查询SQL

整理了postgresql的系统表关联的常用SQL，如下：

--查看数据库  www.2cto.com  

select * from pg_database;

 

--查看表空间

select * from pg_tablespace;

 

--查看语言

select * from pg_language;

 

--查看角色用户

select * from pg_user;

select * from pg_shadow;

select * from pg_roles;

 

--查看会话进程

select * from pg_stat_activity;

 

--查看表

SELECT * FROM pg_tables where schemaname = 'public';

 

--查看表字段

select * from information_schema.columns where table_schema = 'public' and table_name = 'pf_vip_org';

 

--查看视图

select * from pg_views where schemaname = 'public';

select * from information_schema.views where table_schema = 'public';

 

--查看触发器

select * from information_schema.triggers;

 

--查看序列

select * from information_schema.sequences where sequence_schema = 'public';

 

 --查看约束

select * from pg_constraint where contype = 'p'  

--u unique,p primary,f foreign,c check,t trigger,x exclusion

 

select a.relname as table_name,b.conname as constraint_name,b.contype as constraint_type from pg_class a,pg_constraint b where a.oid = b.conrelid and a.relname = 'cc';

 

--查看索引

select * from pg_index ;

 

--查看表上存在哪些索引以及大小

select relname,n.amname as index_type from pg_class m,pg_am n where m.relam = n.oid and m.oid in (

select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'cc');

 

SELECT c.relname,c2.relname, c2.relpages*8 as size_kb

FROM pg_class c, pg_class c2, pg_index i

WHERE c.relname = 'cc' AND

c.oid = i.indrelid AND

c2.oid = i.indexrelid

ORDER BY c2.relname; 

 

--查看索引定义

select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'cc';

select pg_get_indexdef(b.indexrelid);

 

--查看过程函数定义

select oid,* from pg_proc where proname = 'insert_platform_action_exist'; --oid = 24610

select * from pg_get_functiondef(24610);

 

--查看表大小(不含索引等信息)

select pg_relation_size('cc');                         --368640 byte

select pg_size_pretty(pg_relation_size('cc'))   --360 kB

 

--查看DB大小

select pg_size_pretty(pg_database_size('smiletao'));   --12M

 

--查看服务器DB运行状态

[postgres@eyar ~]$ pg_ctl status -D $PGDATA

pg_ctl: server is running (PID: 2373)

/home/postgres/bin/postgres "-D" "/database/pgdata" 

 

--查看每个DB的使用情况(读,写,缓存,更新,事务等)

select * from pg_stat_database

 

--查看索引的使用情况

select * from pg_stat_user_indexes;

 

--查看表所对应的数据文件路径与大小

SELECT pg_relation_filepath(oid), relpages FROM pg_class WHERE relname = 'empsalary';

 

--查看索引与相关字段及大小

 SELECT n.nspname AS schema_name,

        r.rolname as table_owner,

       bc.relname AS table_name,

       ic.relname AS index_name,

       a.attname  AS column_name,

       bc.relpages*8 as index_size_kb     

  FROM pg_namespace n,

       pg_class bc,             -- base class

       pg_class ic,             -- index class

       pg_index i,

       pg_attribute a,           -- att in base

       pg_roles r

  WHERE bc.relnamespace = n.oid

     and i.indrelid = bc.oid

     and i.indexrelid = ic.oid

     and bc.relowner = r.oid

     and i.indkey[0] = a.attnum

     and i.indnatts = 1

     and a.attrelid = bc.oid

     and n.nspname = 'public'

     and bc.relname = 'cc'

  ORDER BY schema_name, table_name, index_name, attname;

 

--查看PG锁

select * from pg_locks;

 

备注：relpages*8 是实际所占磁盘大小

 

--查看表空间大小

select pg_tablespace_size('pg_default');

 

--查看序列与表的对应关系

  WITH fq_objects AS (SELECT c.oid,c.relname AS fqname ,

                           c.relkind, c.relname AS relation

                    FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace ),

 

     sequences AS (SELECT oid,fqname FROM fq_objects WHERE relkind = 'S'), 

     tables    AS (SELECT oid, fqname FROM fq_objects WHERE relkind = 'r' ) 

         SELECT

       s.fqname AS sequence,

       '->' as depends,

       t.fqname AS table

      FROM

       pg_depend d JOIN sequences s ON s.oid = d.objid 

                 JOIN tables t ON t.oid = d.refobjid 

          WHERE

       d.deptype = 'a' and t.fqname = 'cc';