您可以获得总关系大小和关系大小，这可能取决于您的表关系。 下面是如何获取数据库中的前100个表:

SELECT schemaname                                    AS table_schema,
       relname                                       AS table_name,
       PG_SIZE_PRETTY(PG_TOTAL_RELATION_SIZE(relid)) AS total_size,
       PG_SIZE_PRETTY(PG_RELATION_SIZE(relid))       AS data_size,
       PG_SIZE_PRETTY(PG_TOTAL_RELATION_SIZE(relid) - PG_RELATION_SIZE(relid))
                                                     AS external_size
FROM pg_catalog.pg_statio_user_tables
ORDER BY PG_TOTAL_RELATION_SIZE(relid) DESC,
         PG_RELATION_SIZE(relid) DESC
LIMIT 100;

我需要找出哪些表占用了最多的空间。

根据其他人的回答，我使用了这个问题:

select table_name, pg_size_pretty( pg_relation_size(quote_ident(table_name)) )
from information_schema.tables
where table_schema = 'public'
order by pg_relation_size(quote_ident(table_name)) desc

得到如下结果:

table_name              pg_size_pretty
--------------------------------------
trade_binance           96 GB
closs_v2_binance_stash  46 GB
closs_bitfinex_stash    5725 MB
trade_bitfinex          5112 MB
...
api_requests            0 bytes
trade_huobi             0 bytes

我应该买个更大的固态硬盘。

select table_name,n_live_tup, pg_size_pretty(pg_relation_size(table_name))
from information_schema.tables
inner join pg_stat_user_tables  on table_name=relname
where table_schema = 'public'
order by 2 desc

另一种替代方法

 select uv.a tablename, pg_size_pretty(uv.b) sizepretty 
 from (select tb.tablename a, pg_table_size('schemaname.'||tb.tablename::text) b 
        from pg_tables tb 
        where tb.schemaname ilike 'schemaname' 
        order by 2 desc
       ) uv

SELECT
   relname as "Table",
   pg_size_pretty(pg_total_relation_size(relid)) As "Size",
   pg_size_pretty(pg_total_relation_size(relid) - pg_relation_size(relid)) as "External Size"
   FROM pg_catalog.pg_statio_user_tables ORDER BY pg_total_relation_size(relid) DESC;

从这里截取https://wiki-bsse.ethz.ch/display/ITDOC/Check+size+of+tables+and+objects+in+PostgreSQL+database

这将显示模式名、表名、size pretty和size(排序所需)。

SELECT
  schema_name,
  relname,
  pg_size_pretty(table_size) AS size,
  table_size

FROM (
       SELECT
         pg_catalog.pg_namespace.nspname           AS schema_name,
         relname,
         pg_relation_size(pg_catalog.pg_class.oid) AS table_size

       FROM pg_catalog.pg_class
         JOIN pg_catalog.pg_namespace ON relnamespace = pg_catalog.pg_namespace.oid
     ) t
WHERE schema_name NOT LIKE 'pg_%'
ORDER BY table_size DESC;

我基于PostgreSQL数据库中具有大小(相对大小和绝对大小)的模式列表的解决方案来构建它