Postgres - Index Summary

Here's a sample query to pull the number of rows, indexes, and some info about those indexes for each table. Ditch the pg_size_pretty if you’re on an ancient (<= 8.2) version)

SELECT
pg_class.relname,
pg_size_pretty(pg_class.reltuples::bigint) AS rows_in_bytes,
pg_class.reltuples AS num_rows,
count(indexname) AS number_of_indexes,
CASE WHEN x.is_unique = 1 THEN 'Y'
ELSE 'N'
END AS UNIQUE,
SUM(case WHEN number_of_columns = 1 THEN 1
ELSE 0
END) AS single_column,
SUM(case WHEN number_of_columns IS NULL THEN 0
WHEN number_of_columns = 1 THEN 0
ELSE 1
END) AS multi_column
FROM pg_namespace
LEFT OUTER JOIN pg_class ON pg_namespace.oid = pg_class.relnamespace
LEFT OUTER JOIN
(SELECT indrelid,
max(CAST(indisunique AS integer)) AS is_unique
FROM pg_index
GROUP BY indrelid) x
ON pg_class.oid = x.indrelid
LEFT OUTER JOIN
( SELECT c.relname AS ctablename, ipg.relname AS indexname, x.indnatts AS number_of_columns FROM pg_index x
JOIN pg_class c ON c.oid = x.indrelid
JOIN pg_class ipg ON ipg.oid = x.indexrelid )
AS foo
ON pg_class.relname = foo.ctablename
WHERE
pg_namespace.nspname='public'
AND pg_class.relkind = 'r'
GROUP BY pg_class.relname, pg_class.reltuples, x.is_unique
ORDER BY 2;

Source: https://wiki.postgresql.org/wiki/Index_Maintenance