How do you find the disk size of a Postgres / PostgreSQL table and its indexes

Question

I'm coming to Postgres from Oracle and looking for a way to find the table and index size in terms of bytes/MB/GB/etc, or even better the size for all tables. In Oracle I had a nasty long query that looked at user_lobs and user_segments to give back an answer. I assume in Postgres there's something I can use in the information_schema tables, but I'm not seeing where. Thanks in advance.

Answer 1

Try the Database Object Size Functions. An example:

SELECT pg_size_pretty(pg_total_relation_size('"schema"."Table"'));

For all tables, something along the lines of:

SELECT
    table_schema || '.' || table_name AS table_full_name,
    pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) AS size
FROM information_schema.tables
ORDER BY
    pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') DESC

Answer 2

PostgreSQL tables have three components: the table itself, any indexes on it, and potentially TOAST data. There's a couple of examples showing how to slide and dice the available information various ways at http://wiki.postgresql.org/wiki/Disk_Usage