On Wed, Nov 29, 2017 at 11:05 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On 25 September 2017 at 22:34, Kyotaro HORIGUCHI > <horiguchi.kyot...@lab.ntt.co.jp> wrote: > >>> > Here is a small patch that skips scanning btree index if no pending >>> > deleted pages exists. >>> > It detects this situation by comparing pages_deleted with pages_free. >> >> It seems to work to prevent needless cleanup scans. > > So this leaves us in the situation that > > 1. Masahiko's patch has unresolved problems > 2. Yura's patch works and is useful > > Unless there is disagreement on the above, it seems we should apply > Yura's patch (an edited version, perhaps). >
IIRC the patches that makes the cleanup scan skip has a problem pointed by Peter[1], that is that we stash an XID when a btree page is deleted, which is used to determine when it's finally safe to recycle the page. Yura's patch doesn't have that problem? [1] https://www.postgresql.org/message-id/CAH2-Wz%3D1%3Dt5fcGGfarQGcAWBqaCh%2BdLMjpYCYHpEyzK8Qg6OrQ%40mail.gmail.com Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center
