We have traced this to the *addition* of a two-column index.
> -Original Message-
> From: pgsql-performance-ow...@postgresql.org [mailto:pgsql-
> performance-ow...@postgresql.org] On Behalf Of Jim Garrison
> Sent: Wednesday, September 25, 2013 8:58 AM
> To: pgsql-performance@postgresql.org
We have traced this to the *addition* of a two-column index.
The two tables in question both have single-column indexes on two foreign keys,
say columns A and B. The query joins the two large tables on A and B.
With only the two indexes, the query plan does a bitmap AND on the index scan
re
On Wed, Sep 25, 2013 at 8:58 AM, Jim Garrison wrote:
> I spent about a week optimizing a query in our performance-testing
> environment, which has hardware similar to production.
>
> I was able to refactor the query and reduce the runtime from hours to
> about 40 seconds, through the use of CTEs
