Re: [PERFORM] MAX() and multi-column index on a partitioned table?
Dave Johansen davejohan...@gmail.com writes: I'm trying to call MAX() on the first value of a multi-column index of a partitioned table and the planner is choosing to do a sequential scan instead of an index scan. Is there something I can do to fix this? What PG version are you using? 9.1 or newer should know how to do this with a merge append of several indexscans. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
Re: [PERFORM] MAX() and multi-column index on a partitioned table?
On Fri, May 22, 2015 at 3:42 PM, Tom Lane t...@sss.pgh.pa.us wrote: Dave Johansen davejohan...@gmail.com writes: I'm trying to call MAX() on the first value of a multi-column index of a partitioned table and the planner is choosing to do a sequential scan instead of an index scan. Is there something I can do to fix this? What PG version are you using? 9.1 or newer should know how to do this with a merge append of several indexscans. Sorry, I should have mentioned that in the original email. I'm using 8.4.20 on RHEL 6. From your reply, it sounds like this is the expected behavior for 8.4 and 9.0. Is that the case? Thanks, Dave
Re: [PERFORM] MAX() and multi-column index on a partitioned table?
Dave Johansen davejohan...@gmail.com writes: On Fri, May 22, 2015 at 3:42 PM, Tom Lane t...@sss.pgh.pa.us wrote: What PG version are you using? 9.1 or newer should know how to do this with a merge append of several indexscans. Sorry, I should have mentioned that in the original email. I'm using 8.4.20 on RHEL 6. From your reply, it sounds like this is the expected behavior for 8.4 and 9.0. Is that the case? Yeah, pre-9.1 is not very bright about that. You could factor the query manually, perhaps, though it's surely a pain in the neck. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
