On 10 October 2011 18:23, Bruce Momjian <br...@momjian.us> wrote: > I talked to Robert Haas and he said that index-only scans do not > optimize COUNT(*). Is this something we can do for PG 9.2? Is anyone > working on this?
Yes it does, provided that there is an appropriate WHERE clause. But yes, I think we definitely want this if it's relatively easy. In addition to this, it's not always easy to get it to use an index-only scan even if it's going to significantly faster. I'm assuming some supporting planner work needs to be added too. -- Thom Brown Twitter: @darkixion IRC (freenode): dark_ixion Registered Linux user: #516935 EnterpriseDB UK: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
