Re: [HACKERS] [PERFORM] No hash join across partitioned tables?
On Sun, Jun 13, 2010 at 11:47 PM, Robert Haas robertmh...@gmail.com wrote: Proposed patch attached. Hearing no objections, I have committed this patch. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] No hash join across partitioned tables?
On Thu, Jun 10, 2010 at 9:29 AM, Robert Haas robertmh...@gmail.com wrote: (moving to -hackers) On Wed, Jun 9, 2010 at 4:11 PM, Tom Lane t...@sss.pgh.pa.us wrote: Robert Haas robertmh...@gmail.com writes: In going back through emails I had marked as possibly needing another look before 9.0 is released, I came across this issue again. As I understand it, analyze (or analyse) now collects statistics for both the parent individually, and for the parent and its children together. However, as I further understand it, autovacuum won't actually fire off an analyze unless there's enough activity on the parent table considered individually to warrant it. So if you have an empty parent and a bunch of children with data in it, your stats will still stink, unless you analyze by hand. Check. Assuming my understanding of the problem is correct, we could: (a) fix it, (b) document that you should consider periodic manual analyze commands in this situation, or (c) do nothing. Thoughts? The objections to (a) are that it might result in excessive ANALYZE work if not done intelligently, and that we haven't got a patch ready anyway. I would have liked to get to this for 9.0 but I feel it's a bit late now. I guess I can't really disagree with that. Should we try to document this in some way? Proposed patch attached. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company analyze-inherit-docs.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] [PERFORM] No hash join across partitioned tables?
(moving to -hackers) On Wed, Jun 9, 2010 at 4:11 PM, Tom Lane t...@sss.pgh.pa.us wrote: Robert Haas robertmh...@gmail.com writes: In going back through emails I had marked as possibly needing another look before 9.0 is released, I came across this issue again. As I understand it, analyze (or analyse) now collects statistics for both the parent individually, and for the parent and its children together. However, as I further understand it, autovacuum won't actually fire off an analyze unless there's enough activity on the parent table considered individually to warrant it. So if you have an empty parent and a bunch of children with data in it, your stats will still stink, unless you analyze by hand. Check. Assuming my understanding of the problem is correct, we could: (a) fix it, (b) document that you should consider periodic manual analyze commands in this situation, or (c) do nothing. Thoughts? The objections to (a) are that it might result in excessive ANALYZE work if not done intelligently, and that we haven't got a patch ready anyway. I would have liked to get to this for 9.0 but I feel it's a bit late now. I guess I can't really disagree with that. Should we try to document this in some way? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
