PostgreSQL查看資料庫，索引，資料表空間大小

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執行個體講解 3.1 查看儲存一個指定的數值需要的位元組數 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('中國');                          pg_column_size ----------------               7 (1 row) david=# 3.2 查看資料庫大小 查看未經處理資料 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 資料庫大小 david=# select pg_database_size('david');  pg_database_size ------------------         190534776 (1 row) david=# 查看所有資料庫大小 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=# 這樣查出來的結果，看上去太長了，不太容易讀數。 3.3 以人性化的方式顯示大小 david=# select pg_size_pretty(pg_database_size('david'));  pg_size_pretty ----------------  182 MB (1 row) david=# 3.4 查看單索引大小 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 兩個索引大小加起來差不多等於上面pg_indexes_size() 查詢出來的索引大小。 3.6 查看指定schema 裡所有的索引大小，按從大到小的順序排列。 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() 函數查看 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 查看指定表的總大小 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 裡所有的表大小，按從大到小的順序排列。 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 查看錶空間大小 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=# 另一種查看方法： 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=#