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.

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;

Edit: Here's the query submitted by @phord, for convenience:

SELECT
    table_name,
    pg_size_pretty(table_size) AS table_size,
    pg_size_pretty(indexes_size) AS indexes_size,
    pg_size_pretty(total_size) AS total_size
FROM (
    SELECT
        table_name,
        pg_table_size(table_name) AS table_size,
        pg_indexes_size(table_name) AS indexes_size,
        pg_total_relation_size(table_name) AS total_size
    FROM (
        SELECT ('"' || table_schema || '"."' || table_name || '"') AS table_name
        FROM information_schema.tables
    ) AS all_tables
    ORDER BY total_size DESC
) AS pretty_sizes;

I've modified it slightly to use pg_table_size() to include metadata and make the sizes add up.