Hi, On 11/02/2017 06:45 PM, Alvaro Herrera wrote: > Tomas Vondra wrote: > >> Unfortunately, I think we still have a problem ... I've been wondering >> if we end up producing correct indexes, so I've done a simple test. > > Here's a proposed patch that should fix this problem (and does, in my > testing). Would you please give it a try? > > This patch changes two things: > > 1. in VACUUM or brin_summarize_new_values, we only process fully loaded > ranges, and ignore the partial range at end of table. > > 2. when summarization is requested on the partial range at the end of a > table, we acquire extension lock on the rel, then compute relation size > and run summarization with the lock held. This guarantees that we don't > miss any pages. This is bad for concurrency though, so it's only done > in that specific scenario. >
FWIW this patch fixes the issue for me - I can no longer reproduce the bitmapscan vs. seqscan result discrepancies (even with the extra UPDATE phase). regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
