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
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