为什么我的postgres数据库这么大？

Question

i'm running PostgreSQL 9.4.6 and I have a database that's 78GB found by running

SELECT pg_size_pretty(pg_database_size('<db name>')) As fulldbsize;

In order to track down why my database is so big I've tried the following:-

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;

But when adding up the resulting tables I get to about 15GB.

What's using my up the space in my database? What further commands can I run?

Answer 1

you can also get information about all objects and their respective sizes

 SELECT
 relname AS objectname,
 relkind AS objecttype,
 reltuples AS "#entries", pg_size_pretty(relpages::bigint*8*1024) AS size
 FROM pg_class
 WHERE relpages >= 8
 ORDER BY relpages DESC;

This should detail:

• objectname – The name of the object
• objecttype – r for the table, i for an index, t for toast data, ...
• entries – The estimated number of entries in the object (eg rows)
• size – The size of the object

Answer 2

This will list all objects an their size:

SELECT relname, pg_total_relation_size(oid)
FROM pg_class
ORDER BY 2 DESC;

That should help you account for the database size.