On 15 February 2017 at 08:07, Masahiko Sawada <sawada.m...@gmail.com> wrote: > > It's a bug. Attached latest version patch, which passed make check.
In its current form, I'm not sure this is a good idea. Problems... 1. I'm pretty sure the world doesn't need another VACUUM parameter I suggest that we use the existing vacuum scale factor/4 to reflect that indexes are more sensitive to bloat. 2. The current btree vacuum code requires 2 vacuums to fully reuse half-dead pages. So skipping an index vacuum might mean that second index scan never happens at all, which would be bad. I suggest that we store the number of half-dead pages in the metapage after each VACUUM, so we can decide whether to skip the scan or not. And we use some math like each half-dead page that needs to be reused is worth 250 index entries, so the decision to skip is based upon rows and empty pages, not just recently vacuumed rows. -- Simon Riggs 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
