How do I speed up counting rows in a PostgreSQL table?

Question

We need to count the number of rows in a PostgreSQL table. In our case, no conditions need to be met, and it would be perfectly acceptable to get a row estimate if that sig

Answer 1

Aside from running COUNT() on an indexed field (which hopefully 'id' is) - the next best thing would be to actually cache the row count in some table using a trigger on INSERT. Naturally, you'll be checking the cache instead.

For an approximation you can try this (from https://wiki.postgresql.org/wiki/Count_estimate):

select reltuples from pg_class where relname='tablename';