postgresql dba常用sql查詢語句

轉(zhuǎn)載自： http://blog.itpub.net/30126024/viewspace-2655205/

查看幫助命令

DB=# help --總的幫助

DB=# \h --SQL commands級的幫助

DB=# \? --psql commands級的幫助

按列顯示，類似mysql的\G

DB=# \x

Expanded display is on.

查看DB安裝目錄(最好root用戶執(zhí)行)

find / -name initdb

查看有多少DB實(shí)例在運(yùn)行(最好root用戶執(zhí)行)

find / -name postgresql.conf

查看DB版本

cat $PGDATA/PG_VERSION

psql --version

DB=# show server_version;

DB=# select version();

查看DB實(shí)例運(yùn)行狀態(tài)

pg_ctl status

查看所有數(shù)據(jù)庫

psql –l --查看5432端口下面有多少個(gè)DB

psql –p XX –l --查看XX端口下面有多少個(gè)DB

DB=# \l

DB=# select * from pg_database;

創(chuàng)建數(shù)據(jù)庫

createdb database_name

DB=# \h create database --創(chuàng)建數(shù)據(jù)庫的幫助命令

DB=# create database database_name

進(jìn)入某個(gè)數(shù)據(jù)庫

psql –d dbname

DB=# \c dbname

查看當(dāng)前數(shù)據(jù)庫

DB=# \c

DB=# select current_database();

查看數(shù)據(jù)庫文件目錄

DB=# show data_directory;

cat $PGDATA/postgresql.conf |grep data_directory

cat /etc/init.d/postgresql|grep PGDATA=

lsof |grep 5432得出第二列的PID號再ps –ef|grep PID

查看表空間

select * from pg_tablespace;

查看語言

select * from pg_language;

查詢所有schema，必須到指定的數(shù)據(jù)庫下執(zhí)行

select * from information_schema.schemata;

SELECT nspname FROM pg_namespace;

\dnS

查看表名

DB=# \dt --只能查看到當(dāng)前數(shù)據(jù)庫下public的表名

DB=# SELECT tablename FROM pg_tables WHERE tablename NOT LIKE 'pg%' AND tablename NOT LIKE 'sql_%' ORDER BY tablename;

DB=# SELECT * FROM information_schema.tables WHERE table_name='ff_v3_ff_basic_af';

查看表結(jié)構(gòu)

DB=# \d tablename

DB=# select * from information_schema.columns where table_schema='public' and table_name='XX';

查看索引

DB=# \di

DB=# select * from pg_index;

查看視圖

DB=# \dv

DB=# select * from pg_views where schemaname = 'public';

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

查看觸發(fā)器

DB=# select * from information_schema.triggers;

查看序列

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

查看約束

DB=# select * from pg_constraint where contype = 'p'

DB=# 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XX數(shù)據(jù)庫的大小

SELECT pg_size_pretty(pg_database_size('XX')) As fulldbsize;

查看所有數(shù)據(jù)庫的大小

select pg_database.datname, pg_size_pretty (pg_database_size(pg_database.datname)) AS size from pg_database;

查看各數(shù)據(jù)庫數(shù)據(jù)創(chuàng)建時(shí)間：

select datname,(pg_stat_file(format('%s/%s/PG_VERSION',case when spcname='pg_default' then 'base' else 'pg_tblspc/'||t2.oid||'/PG_11_201804061/' end, t1.oid))).* from pg_database t1,pg_tablespace t2 where t1.dattablespace=t2.oid;

按占空間大小，順序查看所有表的大小

select relname, pg_size_pretty(pg_relation_size(relid)) from pg_stat_user_tables where schemaname='public' order by pg_relation_size(relid) desc;

按占空間大小，順序查看索引大小

select indexrelname, pg_size_pretty(pg_relation_size(relid)) from pg_stat_user_indexes where schemaname='public' order by pg_relation_size(relid) desc;

查看參數(shù)文件

DB=# show config_file;

DB=# show hba_file;

DB=# show ident_file;

查看當(dāng)前會話的參數(shù)值

DB=# show all;

查看參數(shù)值

select * from pg_file_settings

查看某個(gè)參數(shù)值,比如參數(shù)work_mem

DB=# show work_mem

修改某個(gè)參數(shù)值,比如參數(shù)work_mem

DB=# alter system set work_mem='8MB'

--使用alter system命令將修改postgresql.auto.conf文件，而不是postgresql.conf，這樣可以很好的保護(hù)postgresql.conf文件，加入你使用很多alter system命令后搞的一團(tuán)糟，那么你只需要?jiǎng)h除postgresql.auto.conf，再執(zhí)行pg_ctl reload加載postgresql.conf文件即可實(shí)現(xiàn)參數(shù)的重新加載。

查看是否歸檔

DB=# show archive_mode;

查看運(yùn)行日志的相關(guān)配置，運(yùn)行日志包括Error信息，定位慢查詢SQL，數(shù)據(jù)庫的啟動(dòng)關(guān)閉信息，checkpoint過于頻繁等的告警信息。

show logging_collector;--啟動(dòng)日志收集

show log_directory;--日志輸出路徑

show log_filename;--日志文件名

show log_truncate_on_rotation;--當(dāng)生成新的文件時(shí)如果文件名已存在，是否覆蓋同名舊文件名

show log_statement;--設(shè)置日志記錄內(nèi)容

show log_min_duration_statement;--運(yùn)行XX毫秒的語句會被記錄到日志中，-1表示禁用這個(gè)功能，0表示記錄所有語句，類似mysql的慢查詢配置

查看wal日志的配置，wal日志就是redo重做日志

存放在data_directory/pg_wal目錄

查看當(dāng)前用戶

DB=# \c

DB=# select current_user;

查看所有用戶

DB=# select * from pg_user;

DB=# select * from pg_shadow;

查看所有角色

DB=# \du

DB=# select * from pg_roles;

查詢用戶XX的權(quán)限，必須到指定的數(shù)據(jù)庫下執(zhí)行

select * from information_schema.table_privileges where grantee='XX';

創(chuàng)建用戶XX，并授予超級管理員權(quán)限

create user XXX SUPERUSER PASSWORD '123456'

創(chuàng)建角色，賦予了login權(quán)限，則相當(dāng)于創(chuàng)建了用戶，在pg_user可以看到這個(gè)角色

create role "user1" superuser;--pg_roles有user1，pg_user和pg_shadow沒有user1

alter role "user1" login;--pg_user和pg_shadow也有user1了

授權(quán)

DB=# \h grant

GRANT ALL PRIVILEGES ON schema schemaname TO dbuser;

grant ALL PRIVILEGES on all tables in schema fds to dbuser;

GRANT ALL ON tablename TO user;

GRANT ALL PRIVILEGES ON DATABASE dbname TO dbuser;

grant select on all tables in schema public to dbuser;--給用戶讀取public這個(gè)schema下的所有表

GRANT create ON schema schemaname TO dbuser;--給用戶授予在schema上的create權(quán)限，比如create table、create view等

GRANT USAGE ON schema schemaname TO dbuser;

grant select on schema public to dbuser;--報(bào)錯(cuò)ERROR: invalid privilege type SELECT for schema

--USAGE：對于程序語言來說，允許使用指定的程序語言創(chuàng)建函數(shù);對于Schema來說，允許查找該Schema下的對象;對于序列來說，允許使用currval和nextval函數(shù);對于外部封裝器來說，允許使用外部封裝器來創(chuàng)建外部服務(wù)器;對于外部服務(wù)器來說，允許創(chuàng)建外部表。

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;

查看索引定義

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);

查看過程函數(shù)定義

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

查看表所對應(yīng)的數(shù)據(jù)文件路徑與大小

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

posegresql查詢當(dāng)前l(fā)sn

1、用到哪些方法：

apple=# select proname from pg_proc where proname like 'pg_%_lsn';

proname

---------------------------------

pg_current_wal_flush_lsn

pg_current_wal_insert_lsn

pg_current_wal_lsn

pg_last_wal_receive_lsn

pg_last_wal_replay_lsn

2、查詢當(dāng)前的lsn值：

apple=# select pg_current_wal_lsn();

pg_current_wal_lsn

--------------------------

0/45000098

3、查詢當(dāng)前l(fā)sn對應(yīng)的日志文件

select pg_walfile_name('0/1732DE8');

4、查詢當(dāng)前l(fā)sn在日志文件中的偏移量

SELECT * FROM pg_walfile_name_offset(pg_current_wal_lsn());

切換pg_wal日志

select pg_switch_wal();

清理pg_wal日志

pg_archivecleanup /postgresql/pgsql/data/pg_wal 000000010000000000000005

表示刪除000000010000000000000005之前的所有日志

--pg_wal日志沒有設(shè)置保留周期的參數(shù)，即沒有類似mysql的參數(shù)expire_logs_days，pg_wal日志永久保留，除非shell腳步刪除幾天前或pg-rman備份時(shí)候設(shè)置保留策略

查詢有哪些slot，任意一個(gè)數(shù)據(jù)庫下都可以查，查詢的結(jié)果都一樣

select * from pg_replication_slots;