postgresql常用SQL

1. --查看数据库
2. select * from pg_database;
4. --查看表空间
5. select * from pg_tablespace;
7. --查看语言
8. select * from pg_language;
10. --查看角色用户
11. select * from pg_user;
12. select * from pg_shadow;
13. select * from pg_roles;
15. --查看会话进程
16. select * from pg_stat_activity;
18. --查看表
19. SELECT * FROM pg_tables where schemaname = 'public';
21. --查看表字段
22. select * from information_schema.columns where table_schema = 'public' and table_name = 'pf_vip_org';
24. --查看视图
25. select * from pg_views where schemaname = 'public';
26. select * from information_schema.views where table_schema = 'public';
28. --查看触发器
29. select * from information_schema.triggers;
31. --查看序列
32. select * from information_schema.sequences where sequence_schema = 'public';
34. --查看约束
35. select * from pg_constraint where contype = 'p' 
36. --u unique,p primary,f foreign,c check,t trigger,x exclusion
38. 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';
40. --查看索引
41. select * from pg_index ;
43. --查看表上存在哪些索引以及大小
44. select relname,n.amname as index_type from pg_class m,pg_am n where m.relam = n.oid and m.oid in (
45. select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'cc');
47. SELECT c.relname,c2.relname, c2.relpages*8 as size_kb
48. FROM pg_class c, pg_class c2, pg_index i
49. WHERE c.relname = 'cc' AND
50. c.oid = i.indrelid AND
51. c2.oid = i.indexrelid
52. ORDER BY c2.relname;
54. --查看索引定义
55. select b.indexrelid from pg_class a,pg_index b where a.oid = b.indrelid and a.relname = 'cc';
56. select pg_get_indexdef(b.indexrelid);
58. --查看过程函数定义
59. select oid,* from pg_proc where proname = 'insert_platform_action_exist'; --oid = 24610
60. select * from pg_get_functiondef(24610);
62. --查看表大小(不含索引等信息)
63. select pg_relation_size('cc');                         --368640 byte
64. select pg_size_pretty(pg_relation_size('cc'))   --360 kB
66. --查看DB大小
67. select pg_size_pretty(pg_database_size('smiletao'));   --12M
69. --查看服务器DB运行状态
70. [postgres@eyar ~]$ pg_ctl status -D $PGDATA
71. pg_ctl: server is running (PID: 2373)
72. /home/postgres/bin/postgres "-D" "/database/pgdata"
74. --查看每个DB的使用情况(读,写,缓存,更新,事务等)
75. select * from pg_stat_database
77. --查看索引的使用情况
78. select * from pg_stat_user_indexes;
80. --查看表所对应的数据文件路径与大小
81. SELECT pg_relation_filepath(oid), relpages FROM pg_class WHERE relname = 'empsalary';
83. --查看索引与相关字段及大小
84. SELECT n.nspname AS schema_name,
85.         r.rolname as table_owner,
86.        bc.relname AS table_name,
87.        ic.relname AS index_name,
88.        a.attname  AS column_name,
89.        bc.relpages*8 as index_size_kb    
90.   FROM pg_namespace n,
91.        pg_class bc,             -- base class
92.        pg_class ic,             -- index class
93.        pg_index i,
94.        pg_attribute a,           -- att in base
95.        pg_roles r
96.   WHERE bc.relnamespace = n.oid
97.      and i.indrelid = bc.oid
98.      and i.indexrelid = ic.oid
99.      and bc.relowner = r.oid
100.      and i.indkey[0] = a.attnum
101.      and i.indnatts = 1
102.      and a.attrelid = bc.oid
103.      and n.nspname = 'public'
104.      and bc.relname = 'cc'
105.   ORDER BY schema_name, table_name, index_name, attname;
107. --查看PG锁
108. select * from pg_locks;
110. 备注：relpages*8 是实际所占磁盘大小
112. --查看表空间大小
113. select pg_tablespace_size('pg_default');
115. --查看序列与表的对应关系
116.   WITH fq_objects AS (SELECT c.oid,c.relname AS fqname ,
117.                            c.relkind, c.relname AS relation
118.                     FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace ),
120.      sequences AS (SELECT oid,fqname FROM fq_objects WHERE relkind = 'S'),
121.      tables    AS (SELECT oid, fqname FROM fq_objects WHERE relkind = 'r' )
122.          SELECT
123.        s.fqname AS sequence,
124.        '->' as depends,
125.        t.fqname AS table
126.       FROM
127.        pg_depend d JOIN sequences s ON s.oid = d.objid
128.                  JOIN tables t ON t.oid = d.refobjid
129.           WHERE
130.        d.deptype = 'a' and t.fqname = 'cc';