postgresql学习

如何查询数据库表的大小
playstore_log=> select pg_size_pretty(pg_relation_size(‘playstore_logs_browse‘));
pg_size_pretty
----------------
15 GB
(1 row)

查询数据库的大小
playstore_log=> select pg_size_pretty(pg_database_size(‘playstore_log‘));
pg_size_pretty
----------------
26 GB
(1 row)

查询表
\dt

执行sql脚本
su - postges
cat agent.sql|psql -p1921 agent

遇到的问题

[root@localhost ~]# su - postgres
[postgres@localhost ~]$ psql -p 1921 -U base
Welcome to psql 8.1.23 (server 9.0.2), the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
      \h for help with SQL commands
      \? for help with psql commands
      \g or terminate with semicolon to execute query
      \q to quit

WARNING:  You are connected to a server with major version 9.0,
but your psql client is major version 8.1.  Some backslash commands,
such as \d, might not work properly.

base=> \dt ----------------查询表
                 List of relations
Schema |          Name           | Type  |  Owner  
--------+-------------------------+-------+----------
public | sys_author              | table | postgres
public | sys_district            | table | postgres
public | sys_function            | table | postgres

base=> \d sys_author-------查询表结构，报错了。
ERROR:  column "reltriggers" does not exist at character 41
LINE 1: SELECT relhasindex, relkind, relchecks, reltriggers, relhasr...

原因分析：

正常情况是不会出现表结构不能查询的。

Welcome to psql 8.1.23 (server 9.0.2), the PostgreSQL interactive terminal.

大家可以看到，psql命令是8.1版本的，postgresql服务是9.0版本的，所以这个原因就是版本不兼容导致的。

所以要用与postgresql服务对应的psql命令登录才能查询成功。

[root@localhost ~]# /data/soft/pgsql/bin/psql -p 1921 -U postgres android_base------以postgres身份登录android_base库

psql (9.0.2)
Type "help" for help.

android_base=# \dt
          List of relations
Schema |    Name    | Type  |  Owner  
--------+------------+-------+----------
public | tbl_locale | table | postgres
public | tbl_lookup | table | postgres
(2 rows)

android_base=# \d tbl_lookup
                         Table "public.tbl_lookup"
  Column    |            Type             |            Modifiers            
-------------+-----------------------------+---------------------------------
id          | bigint                      | not null
create_time | timestamp(6) with time zone |
value       | character varying(100)      | default NULL::character varying
key         | character varying(100)      | default NULL::character varying
type        | character varying(100)      | default NULL::character varying
Indexes:
   "tbl_lookup_pkey" PRIMARY KEY, btree (id)

查询成功。

未完待续

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