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3.pg客户端工具使用

2021-10-06 11:07:16  阅读：225  来源： 互联网

标签：psql test1 lhc postgres pgsql pg 工具 copy 客户端


文章目录

客户端工具

一、使用psql连接数据库

psql postgres postgres
[root@oracle ~]# su - pgsql
[pgsql@oracle ~]$psql postgres postgres
psql (13.4)
Type "help" for help.
第一个postgres表示库名
第二个postgres表示用户名

1.1.创建用户

create role pguser with encrypted password 'pguser';
create user lhc with password 'lhc';

1.2.创建表空间目录

mkdir -p /data/postgresql/pgdata/tablespace/ts_lhc

1.3.创建表空间

create tablespace ts_lhc owner lhc location '/data/postgresql/pgdata/tablespace/ts_lhc';

1.4.创建数据库

create database lhcdb with owner = lhc tablespace = ts_lhc;
create database lhcdb 
with owner = pguser 
template = template0
encoding = 'UTF8' 
tablespace = ts_lhc;

ALTER DATABASE lhcdb SET TABLESPACE ts_lhc;

1.5.赋权

grant all privileges on database lhcdb to lhc with grant option;
grant all on tablespace ts_lhc to lhc;
grant all on database mydb to pguser with grant option;

1.6.创建schema

create schema lhc;
grant usage on schema lhc to lhc;

create schema lhcPrivate authorization lhc;
create schema authorization lhc;

1.7.远程连接数据库

[pgsql@oracle ~]$psql -U lhc -h 10.206.132.17 -p 5432 -d postgres
Password for user lhc:
psql (13.4)
Type "help" for help.

查看Schema
postgres=# \dn
    List of schemas
    Name    |  Owner
------------+----------
 lhc        | lhc
 lhcprivate | lhc
 public     | postgres
(3 rows)

二、psql元命令的介绍

2.1.\l查看数据库列表

postgres@[local:/data/postgresql/pgdata]:5432=#\l
                                 List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges
-----------+----------+----------+------------+------------+-----------------------
 lhcdb     | lhc      | UTF8     | en_US.utf8 | en_US.utf8 |
 postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
(4 rows)

postgres-#

postgres-# \l+
                                                                   List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges   |  Size   | Tablespace |
   Description
-----------+----------+----------+------------+------------+-----------------------+---------+------------+--------------------------------------------
 lhcdb     | lhc      | UTF8     | en_US.utf8 | en_US.utf8 | =Tc/lhc              +| 7729 kB | ts_lhc     |
           |          |          |            |            | lhc=C*T*c*/lhc        |         |            |
 postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 |                       | 7877 kB | pg_default | default administrative connection database
 template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +| 7729 kB | pg_default | unmodifiable empty database
           |          |          |            |            | postgres=CTc/postgres |         |            |
 template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +| 7729 kB | pg_default | default template for new databases
           |          |          |            |            | postgres=CTc/postgres |         |            |
(4 rows)

2.2.\db查看表空间列表

postgres-# \db
                        List of tablespaces
    Name    |  Owner   |                 Location
------------+----------+-------------------------------------------
 pg_default | postgres |
 pg_global  | postgres |
 ts_lhc     | lhc      | /data/postgresql/pgdata/tablespace/ts_lhc
(3 rows)

2.3.\d查看表的定义

create table lhc.test1 (id int,name text) tablespace ts_lhc;
create table lhc.test2 (id int,name varchar(50)) tablespace ts_lhc;
alter table lhc.test1 add primary key (id);

[pgsql@oracle ~]$psql -U lhc -h 10.206.132.17 -p 5432 -d postgres
Password for user lhc:
psql (13.4)
Type "help" for help.

postgres=> SELECT * FROM pg_catalog.pg_tables WHERE tableowner = 'lhc';
 schemaname | tablename | tableowner | tablespace | hasindexes | hasrules | hastriggers | rowsecurity
------------+-----------+------------+------------+------------+----------+-------------+-------------
 lhc        | test1     | lhc        | ts_lhc     | f          | f        | f           | f
 lhc        | test2     | lhc        | ts_lhc     | f          | f        | f           | f
(2 rows)

postgres@10.206.132.17:5432=>alter table lhc.test1 add primary key (id);
ALTER TABLE
postgres@10.206.132.17:5432=>\d test1
                 Table "lhc.test1"
 Column |  Type   | Collation | Nullable | Default
--------+---------+-----------+----------+---------
 id     | integer |           | not null |
 name   | text    |           |          |
Indexes:
    "test1_pkey" PRIMARY KEY, btree (id)
Tablespace: "ts_lhc"

2.4.查看表、索引占用空间的大小

给测试表lhc.test1插入500百万数据
insert into lhc.test1 (id,name) select n,n||'_francs' from generate_series(1,5000000) n;

postgres@10.206.132.17:5432=>insert into lhc.test1 (id,name) select n,n||'_francs' from generate_series(1,5000000) n;
INSERT 0 5000000

查看表大小\dt+ lhc.test1
postgres@10.206.132.17:5432=>\dt+ lhc.test1
                          List of relations
 Schema | Name  | Type  | Owner | Persistence |  Size  | Description
--------+-------+-------+-------+-------------+--------+-------------
 lhc    | test1 | table | lhc   | permanent   | 249 MB |
(1 row)

查看索引大小\di+ test1_pkey
postgres@10.206.132.17:5432=>\di+ test1_pkey
                                List of relations
 Schema |    Name    | Type  | Owner | Table | Persistence |  Size  | Description
--------+------------+-------+-------+-------+-------------+--------+-------------
 lhc    | test1_pkey | index | lhc   | test1 | permanent   | 107 MB |
(1 row)

2.5.\sf查看函数代码

create or replace function lhc.random_range(integer,integer)
	returns integer
	language sql
as  $function$
	select ($1 + floor(($2 - $1 + 1) * random()))::int4;
	$function$
	
SELECT lhc.random_range(1,10);
postgres@10.206.132.17:5432=>SELECT lhc.random_range(1,10);
 random_range
--------------
            6
(1 row)

postgres@10.206.132.17:5432=>\sf lhc.random_range
CREATE OR REPLACE FUNCTION lhc.random_range(integer, integer)
 RETURNS integer
 LANGUAGE sql
AS $function$
        select ($1 + floor(($2 - $1 + 1) * random()))::int4;
        $function$
postgres@10.206.132.17:5432=>

2.6.设置查询结果输出

postgres@10.206.132.17:5432=>select * from lhc.test1 limit 1;
 id |   name
----+----------
  1 | 1_francs
(1 row)

postgres@10.206.132.17:5432=>\x
Expanded display is on.
postgres@10.206.132.17:5432=>select * from lhc.test1 limit 1;
-[ RECORD 1 ]--
id   | 1
name | 1_francs

2.7.获取元命令对应的SQL代码

psql -U lhc -h 10.206.132.17 -p 5432 -d postgres -E
[pgsql@oracle ~]$psql -U lhc -h 10.206.132.17 -p 5432 -d postgres -E
psql (13.4)
Type "help" for help.

postgres@10.206.132.17:5432=>\db
********* QUERY **********
SELECT spcname AS "Name",
  pg_catalog.pg_get_userbyid(spcowner) AS "Owner",
  pg_catalog.pg_tablespace_location(oid) AS "Location"
FROM pg_catalog.pg_tablespace
ORDER BY 1;
**************************

                        List of tablespaces
    Name    |  Owner   |                 Location
------------+----------+-------------------------------------------
 pg_default | postgres |
 pg_global  | postgres |
 ts_lhc     | lhc      | /data/postgresql/pgdata/tablespace/ts_lhc
(3 rows)

2.8.?元命令列出所有的元命令

postgres@10.206.132.17:5432=>\?
General
  \copyright             show PostgreSQL usage and distribution terms
  \crosstabview [COLUMNS] execute query and display results in crosstab
  \errverbose            show most recent error message at maximum verbosity
  \g [(OPTIONS)] [FILE]  execute query (and send results to file or |pipe);
                         \g with no arguments is equivalent to a semicolon
  \gdesc                 describe result of query, without executing it
  \gexec                 execute query, then execute each value in its result
  \gset [PREFIX]         execute query and store results in psql variables
  \gx [(OPTIONS)] [FILE] as \g, but forces expanded output mode
  \q                     quit psql
  \watch [SEC]           execute query every SEC seconds

Help
  \? [commands]          show help on backslash commands
  \? options             show help on psql command-line options
  \? variables           show help on special variables
  \h [NAME]              help on syntax of SQL commands, * for all commands

2.9.便捷的HELP命令

\h create tablespace
\h元命令后面不接任何sql命令则会列出所有的sql命令。
postgres@10.206.132.17:5432=>\h create tablespace
Command:     CREATE TABLESPACE
Description: define a new tablespace
Syntax:
CREATE TABLESPACE tablespace_name
    [ OWNER { new_owner | CURRENT_USER | SESSION_USER } ]
    LOCATION 'directory'
    [ WITH ( tablespace_option = value [, ... ] ) ]

URL: https://www.postgresql.org/docs/13/sql-createtablespace.html

2.10.列出所有的schema

postgres=> \dn
    List of schemas
    Name    |  Owner
------------+----------
 lhc        | lhc
 lhcprivate | lhc
 public     | postgres
(3 rows)

三、psql导入、导出表数据

psql支持文件数据导入到数据库，也支持数据库表数据导出到文件中。
copy和\copy命令都支持这两类操作，但两者有以下区别:
(1)copy命令是sql命令，\copy是元命令。
(2)copy命令必须具有superuser超级权限，而\copy元命令不需要superuser权限。
(3)copy命令读取或写入数据库服务端主机上的文件，而\copy元命令是从psql客户端主机读取或写入文件。
(4)从性能看，大数据量导出到文件或大文件数据导入数据库，copy比\copy性能高。

3.1.使用copy命令导入导出数据

导入
postgres=> \d lhc.test1
                 Table "lhc.test1"
 Column |  Type   | Collation | Nullable | Default
--------+---------+-----------+----------+---------
 id     | integer |           |          |
 name   | text    |           |          |
Tablespace: "ts_lhc"

/home/pgsql/testData/test_copy_lhc_test1.txt
[pgsql@oracle testData]$cat test_copy_lhc_test1.txt
1       a
2       b
3       c
4       d
5       e

select count(*) from lhc.test1;
postgres@10.206.132.17:5432=#select count(*) from lhc.test1;
 count
-------
     5
(1 row)

copy lhc.test1 from '/home/pgsql/testData/test_copy_lhc_test1.txt';
postgres=# copy lhc.test1 from '/home/pgsql/testData/test_copy_lhc_test1.txt';
COPY 5
postgres=# select * from lhc.test1;
 id | name
----+------
  1 | a
  2 | b
  3 | c
  4 | d
  5 | e
(5 rows)

[pgsql@oracle testData]$psql postgres lhc
psql (13.4)
Type "help" for help.

copy命令必须使用超级用户
postgres=> copy lhc.test1 from '/home/pgsql/testData/test_copy_lhc_test1.txt';
ERROR:  must be superuser or a member of the pg_read_server_files role to COPY from a file
HINT:  Anyone can COPY to stdout or from stdin. psql's \copy command also works for anyone.'

导出
copy lhc.test1 to '/home/pgsql/testData/export_copy_lhc_test1.txt';
copy lhc.test1 to '/home/pgsql/testData/export_copy_lhc_test1.csv';
copy lhc.test1 to '/home/pgsql/testData/export_copy_lhc_test1.csv' with csv header;
with csv header是指导出格式为csv格式并且显示字段名称。

如何仅导出表的一部分数据呢？
copy (select * from lhc.test1 limit 3) to '/home/pgsql/testData/export_limit_lhc_test1.txt';

将表数据输出到标准输出，而且不需要超级用户权限
copy lhc.test1 to stdout;
postgres@10.206.132.17:5432=#copy lhc.test1 to stdout;
1       a
2       b
3       c
4       d
5       e

3.2.使用命令\copy元命令导入导出数据

导出
psql postgres lhc
\copy lhc.test1 to '/home/pgsql/testData/export_copy_test1.txt';

[pgsql@oracle ~]$psql postgres lhc
psql (13.4)
Type "help" for help.

postgres@[local:/data/postgresql/pgdata]:5432=>\copy lhc.test1 to '/home/pgsql/testData/export_copy_test1.txt';
COPY 5

[pgsql@oracle testData]$cat export_copy_test1.txt
1       a
2       b
3       c
4       d
5       e


导入
[pgsql@oracle testData]$cat test_copy_test1.txt
6       f
test_copy_test1.txt
\copy lhc.test1 from '/home/pgsql/testData/test_copy_test1.txt';

postgres=# \copy lhc.test1 from '/home/pgsql/testData/test_copy_test1.txt';
COPY 1

postgres=# select * from lhc.test1;
 id | name
----+------
  1 | a
  2 | b
  3 | c
  4 | d
  5 | e
  6 | f
(6 rows)

注意:小表\copy;大表copy.

四、psql语法和选项介绍

4.1.-A设置非对齐输出模式

psql -c "select * from lhc.test1 where id = 1" postgres lhc
[pgsql@oracle testData]$psql -c "select * from lhc.test1 where id = 1" postgres lhc
 id | name
----+------
  1 | a
(1 row)

[pgsql@oracle testData]$psql -A -c "select * from lhc.test1 where id = 1" postgres lhc
id|name
1|a
(1 row)

4.2.-t只显示记录数据

psql -t -c "select * from lhc.test1 where id = 1" postgres lhc
[pgsql@oracle testData]$psql -t -c "select * from lhc.test1 where id = 1" postgres lhc
  1 | a

[pgsql@oracle testData]$psql -A-t -c "select * from lhc.test1 where id = 1" postgres lhc
[pgsql@oracle testData]$psql -A -t -c "select * from lhc.test1 where id = 1" postgres lhc
1|a

[pgsql@oracle testData]$psql -At -c "select * from lhc.test1 where id = 1" postgres lhc
1|a

4.3.-q不显示输出信息

psql lhcdb lhc
创建schema
create schema lhcPrivate authorization lhc;
create schema authorization lhc;

vim test_q.sql
create table lhc.test_q(id int);
truncate table lhc.test_q;
insert into lhc.test_q values (1);
insert into lhc.test_q values (2);

[pgsql@oracle testData]$psql -q lhcdb lhc -f test_q.sql

五、psql执行sql脚本

5.1.psql执行sql脚本

c选项支持在操作系统层面通过psql向数据库发起sql命令
-c后接执行的sql命令，可以使用单引号或双引号

psql -c "select current_user"
psql -At -c "select current_user"

[pgsql@oracle testData]$psql -c "select current_user"
 current_user
--------------
 postgres
(1 row)

[pgsql@oracle testData]$psql -At -c "select current_user"
postgres

-f参数导入此脚本
cd /home/pgsql/testData
vim test3.sql
create table lhc.test3(id int4);
insert into lhc.test3 values (1); 
insert into lhc.test3 values (2);
insert into lhc.test3 values (3);

psql postgres lhc -f /home/pgsql/testData/test3.sql
[pgsql@oracle testData]$psql postgres lhc -f /home/pgsql/testData/test3.sql
CREATE TABLE
INSERT 0 1
INSERT 0 1
INSERT 0 1

六、psql如何传递变量到sql

6.1.\set元命令方式传递变量

lhcdb=> \set v_id 2
lhcdb=> select * from test_q where id = :v_id;
 id
----
  2
(1 row)

--取消变量
lhcdb=> \set v_id

6.2.psql的-v参数传递变量

[pgsql@oracle testData]$cat test_1.sql
select * from lhc.test_q where id=:v_id;

[pgsql@oracle testData]$psql -v v_id=1 lhcdb lhc -f test_1.sql
 id
----
  1
(1 row)

七、使用psql定制日常维护脚本

7.1.定制日常维护脚本:查询会话

vim ~/.psqlrc
\set select_session 'SELECT pid,usename,datname,query,client_addr,state FROM pg_catalog.pg_stat_activity WHERE pid <> pg_backend_pid() ORDER BY query;'
使用
[pgsql@oracle ~]$psql -U postgres -h 10.206.132.17 -p 5432 -d postgres -E
psql (13.4)
Type "help" for help.
postgres@10.206.132.17:5432=#:select_session

state指进程的状态，主要值为:
active:后台进程正在执行的SQL.
idle:后台进程为空闲状态，等待后续客户端发出的命令.
idle in transaction:后台进程正在事务中，并不是指正在执行SQL.
idle in transaction(aborted):和idle in transaction状态类似，只是事务中的部分SQL异常.

7.2.定制日常维护脚本:查询等待事件

\set wait_event 'SELECT pid,usename,datname,query,client_addr,wait_event_type,wait_event FROM pg_catalog.pg_stat_activity WHERE pid <> pg_backend_pid() AND wait_event IS NOT NULL ORDER BY  wait_event_type;'

7.3.定制日常维护脚本:查询数据库连接数

\set connections 'SELECT datname,usename,client_addr,count(*) count FROM pg_catalog.pg_stat_activity WHERE pid <> pg_backend_pid() GROUP BY 1,2,3 ORDER BY 1,2,4 DESC;'
postgres@10.206.132.17:5432=#:connections
 datname  | usename  | client_addr  | count
----------+----------+--------------+-------
 postgres | postgres | 10.210.44.68 |     2
          | postgres |              |     1
          |          |              |     4
(3 rows)

八、psql亮点功能

8.1.\timing显示SQL执行时间

\timing
lhcdb=> \timing
Timing is on.
lhcdb=> select * from test_q;
 id
----
  1
  2
(2 rows)

Time: 0.603 ms
lhcdb=> \timing
Timing is off.

8.2.\watch反复执行当前sql

以秒为单位，默认为2秒
lhcdb=> select now();
              now
-------------------------------
 2021-09-07 16:13:38.240021+08
(1 row)

lhcdb=> \watch 1
Tue 07 Sep 2021 04:13:55 PM CST (every 1s)

              now
-------------------------------
 2021-09-07 16:13:55.320362+08
(1 row)

Tue 07 Sep 2021 04:13:56 PM CST (every 1s)

              now
-------------------------------
 2021-09-07 16:13:56.339286+08
(1 row)

Tue 07 Sep 2021 04:13:57 PM CST (every 1s)

tab键自动补全
不管用

8.3.psql客户端提示符

vim ~/.psqlrc
\set PROMPT1 '%/@%M:%>%R%#'

%/:当前数据库名称
%M:数据库服务器别名，不是指主机名，显示的是psql的-h参数设置的值；
当连接建立在Unix域套接字上时则是[local].
%>:数据库服务器的端口号.
%n:数据库会话用户名.
%#:如果是超级用户则显示"#"，其他用户显示">".
%p:当前数据库连接的后台进程号.
%R:在PROMPT1中通常显示"=",如果进程被断开则显示"!".


[pgsql@oracle ~]$psql -U postgres -h 10.206.132.17 -d postgres -p 5432
Password for user postgres:
psql (13.4)
Type "help" for help.

postgres@10.206.132.17:5432=#

PROMPT1是指当psql等待新命令发出时的常规提示符，这个提示符使用得最多.

标签：psql,test1,lhc,postgres,pgsql,pg,工具,copy,客户端
来源： https://blog.csdn.net/weixin_40068220/article/details/120620957

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