PostgreSQL查看数据库，索引，表，表空间大小

PostgreSQL查看数据库，索引，表，表空间大小 一、简介 PostgreSQL 提供了多个系统管理函数来查看表，索引，表空间及数据库的大小，下面详细介绍一下。 二、数据库对象尺寸函数 函数名 返回类型 描述 pg_column_size(any) int 存储一个指定的数值需要的字节

PostgreSQL查看数据库，索引，表，表空间大小

一、简介

PostgreSQL 提供了多个系统管理函数来查看表，索引，表空间及数据库的大小，下面详细介绍一下。

二、数据库对象尺寸函数

函数名 返回类型 描述

pg_column_size(any) int 存储一个指定的数值需要的字节数（可能压缩过）

pg_database_size(oid) bigint 指定OID的数据库使用的磁盘空间

pg_database_size(name) bigint 指定名称的数据库使用的磁盘空间

pg_indexes_size(regclass) bigint 关联指定表OID或表名的表索引的使用总磁盘空间

pg_relation_size(relation regclass, fork text) bigint 指定OID或名的表或索引，通过指定fork('main', 'fsm' 或'vm')所使用的磁盘空间

pg_relation_size(relation regclass) bigint pg_relation_size(..., 'main')的缩写

pg_size_pretty(bigint) text Converts a size in bytes expressed as a 64-bit integer into a human-readable format with size units

pg_size_pretty(numeric) text 把以字节计算的数值转换成一个人类易读的尺寸单位

pg_table_size(regclass) bigint 指定表OID或表名的表使用的磁盘空间，除去索引（但是包含TOAST，*空间映射和可视映射）

pg_tablespace_size(oid) bigint 指定OID的表空间使用的磁盘空间

pg_tablespace_size(name) bigint 指定名称的表空间使用的磁盘空间

pg_total_relation_size(regclass) bigint 指定表OID或表名使用的总磁盘空间，包括所有索引和TOAST数据

三、实例讲解

3.1 查看存储一个指定的数值需要的字节数

david=# select pg_column_size(1);

pg_column_size

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

4

(1 row)

david=# select pg_column_size(10000);

pg_column_size

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

4

(1 row)

david=# select pg_column_size('david');

pg_column_size

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

6

(1 row)

david=# select pg_column_size('hello,world');

pg_column_size

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

12

(1 row)

david=# select pg_column_size('2013-04-18 15:17:21.622885+08');

pg_column_size

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

30

(1 row)

david=# select pg_column_size('中国');

pg_column_size

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

7

(1 row)

david=#

3.2 查看数据库大小

查看原始数据

david=# \d test

Table "public.test"

Column | Type | Modifiers

-----------+-----------------------+-----------

id | integer |

name | character varying(20) |

gender | boolean |

join_date | date |

dept | character(4) |

Indexes:

"idx_join_date_test" btree (join_date)

"idx_test" btree (id)

david=# select count(1) from test;

count

---------

1835008

(1 row)

david=#

查看david 数据库大小

david=# select pg_database_size('david');

pg_database_size

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

190534776

(1 row)

david=#

查看所有数据库大小

david=# select pg_database.datname, pg_database_size(pg_database.datname) AS size from pg_database;

datname | size

-----------+-------------

template0 | 6513156

postgres | 6657144

jboss | 6521348

bugs | 6521348

david | 190534776

BMCV3 | 28147135608

mydb | 10990712

template1 | 6521348

(8 rows)

david=#

这样查出来的结果，看上去太长了，不太容易读数。

3.3 以人性化的方式显示大小

david=# select pg_size_pretty(pg_database_size('david'));

pg_size_pretty

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

182 MB

(1 row)

david=#

3.4 查看单索引大小

david=# select pg_relation_size('idx_test');

pg_relation_size

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

41238528

(1 row)

david=# select pg_size_pretty(pg_relation_size('idx_test'));

pg_size_pretty

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

39 MB

(1 row)

david=#

david=# select pg_size_pretty(pg_relation_size('idx_join_date_test'));

pg_size_pretty

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

39 MB

(1 row)

david=#

3.5 查看指定表中所有索引大小

david=# select pg_indexes_size('test');

pg_indexes_size

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

82477056

(1 row)

david=# select pg_size_pretty(pg_indexes_size('test'));

pg_size_pretty

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

79 MB

(1 row)

david=#

idx_test 和idx_join_date_test 两个索引大小加起来差不多等于上面pg_indexes_size() 查询出来的索引大小。

3.6 查看指定schema 里所有的索引大小，按从大到小的顺序排列。

david=# select * from pg_namespace;

nspname | nspowner | nspacl

--------------------+----------+-------------------------------------

pg_toast | 10 |

pg_temp_1 | 10 |

pg_toast_temp_1 | 10 |

pg_catalog | 10 | {postgres=UC/postgres,=U/postgres}

information_schema | 10 | {postgres=UC/postgres,=U/postgres}

public | 10 | {postgres=UC/postgres,=UC/postgres}

(6 rows)

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

indexrelname | pg_size_pretty

-------------------------------+----------------

idx_join_date_test | 91 MB

idx_test | 91 MB

testtable_idx | 1424 kB

city_pkey | 256 kB

city11 | 256 kB

countrylanguage_pkey | 56 kB

sale_pkey | 8192 bytes

track_pkey | 8192 bytes

tbl_partition_201211_joindate | 8192 bytes

tbl_partition_201212_joindate | 8192 bytes

tbl_partition_201301_joindate | 8192 bytes

tbl_partition_201302_joindate | 8192 bytes

tbl_partition_201303_joindate | 8192 bytes

customer_pkey | 8192 bytes

album_pkey | 8192 bytes

item_pkey | 8192 bytes

tbl_partition_201304_joindate | 8192 bytes

tbl_partition_201307_joindate | 8192 bytes

tbl_partition_201305_joindate | 0 bytes

tbl_partition_201306_joindate | 0 bytes

(20 rows)

david=#

3.7 查看指定表大小

david=# select pg_relation_size('test');

pg_relation_size

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

95748096

(1 row)

david=# select pg_size_pretty(pg_relation_size('test'));

pg_size_pretty

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

91 MB

(1 row)

david=#

使用pg_table_size() 函数查看

david=# select pg_table_size('test');

pg_table_size

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

95789056

(1 row)

david=# select pg_size_pretty(pg_table_size('test'));

pg_size_pretty

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

91 MB

(1 row)

david=#

3.8 查看指定表的总大小

david=# select pg_total_relation_size('test');

pg_total_relation_size

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

178266112

(1 row)

david=# select pg_size_pretty(pg_total_relation_size('test'));

pg_size_pretty

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

170 MB

(1 row)

david=#

3.9 查看指定schema 里所有的表大小，按从大到小的顺序排列。

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

relname | pg_size_pretty

-------------------------------+----------------

test | 91 MB

testtable | 1424 kB

city | 256 kB

countrylanguage | 56 kB

country | 40 kB

testcount | 8192 bytes

tbl_partition_201302 | 8192 bytes

tbl_partition_201303 | 8192 bytes

person | 8192 bytes

customer | 8192 bytes

american_state | 8192 bytes

tbl_david | 8192 bytes

emp | 8192 bytes

tbl_partition_201212 | 8192 bytes

tbl_partition_201304 | 8192 bytes

tbl_partition_error_join_date | 8192 bytes

tbl_partition_201211 | 8192 bytes

album | 8192 bytes

tbl_partition_201307 | 8192 bytes

tbl_xulie | 8192 bytes

tbl_partition_201301 | 8192 bytes

sale | 8192 bytes

item | 8192 bytes

track | 8192 bytes

tbl_partition_201306 | 0 bytes

tbl_partition | 0 bytes

tbl_partition_201305 | 0 bytes

person2 | 0 bytes

(28 rows)

david=#

3.10 查看表空间大小

david=# select spcname from pg_tablespace;

spcname

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

pg_default

pg_global

(2 rows)

david=# select pg_tablespace_size('pg_default');

pg_tablespace_size

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

28381579760

(1 row)

david=# select pg_size_pretty(pg_tablespace_size('pg_default'));

pg_size_pretty

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

26 GB

(1 row)

david=#

另一种查看方法：

david=# select pg_tablespace_size('pg_default')/1024/1024 as "SIZE M";

SIZE M

--------

27066

(1 row)

david=# select pg_tablespace_size('pg_default')/1024/1024/1024 as "SIZE G";

SIZE G

--------

26

(1 row)

david=#