pg_relation_size command is not providing size

Question

I need to find size of a table in posgreSQL. I am using following command but it is giving me 0 as an output. Could you please inform me how can I get the size of a table?

INPUT:

select pg_relation_size('tableName');

OUTPUT:

pg_relation_size 

  0

(1 row)

Try using `pg_total_relation_size` instead of `pg_relation_size`. — Ihor Romanchenko, Sep 24 '13 at 06:26
Maybe you have two tables with the same name, one empty in the search empty and one non-empty which is not in search path? Have you tried including schema, e.g. `select pg_relation_size('public.tableName');`? — Tomas Greif, Sep 24 '13 at 09:41

Woodly0 · Answer 1 · 2021-08-30T12:39:41.400

2

I know this is ancient but I just ran into the same issue. It was due to the fact that the table is a partitioned one, so technically it doesn't have a real size. To get the combined size of all the partitions, check out this question.

Or you could simply make use of the inheritance catalog like:

SELECT count(*) AS child_amount, pg_size_pretty(sum(pg_relation_size(inhrelid::regclass))) AS child_size
FROM pg_inherits 
WHERE inhparent='tableName'::regclass;

edited Aug 30 '21 at 12:39

answered Aug 30 '21 at 08:37

Woodly0

187
2
13

Please add further details to expand on your answer, such as working code or documentation citations. – Community Aug 30 '21 at 11:40

score 1 · Answer 2 · answered Sep 24 '13 at 09:37

1

This is probably because tableName is a view.

Example:

CREATE VIEW dummy AS SELECT 1;
SELECT pg_relation_size('dummy');

Result:

 pg_relation_size 
------------------
                0
(1 row)

answered Sep 24 '13 at 09:37

Daniel Vérité

58,074
15
129
156

pg_relation_size command is not providing size

2 Answers2