Peter Geoghegan <p...@bowt.ie> writes: > On Fri, Feb 8, 2019 at 6:00 PM Tom Lane <t...@sss.pgh.pa.us> wrote: >> Yeah, I saw that in the commit message, but didn't really think that >> the release note entry needed to explain it that way. Could be >> argued differently though.
> I'm pretty confident that somebody is going to miss this > functionality, if this account of how the patch helped Yandex is > anything to go by: > https://www.postgresql.org/message-id/7B44397E-5E0A-462F-8148-1C444640FA0B%40simply.name Ugh. Well, hopefully somebody will find a less buggy solution in the future. >>> We may even need to revise the v10 release notes. >> Perhaps just remove that item from the 10.0 notes? > The wording could be changed to reflect the current reality within > GIN. It's still useful that posting trees are only locked when there > are pages to be deleted. The v10 release notes just say Reduce page locking during vacuuming of <acronym>GIN</acronym> indexes (Andrey Borodin) so it doesn't seem like there's any difference at that level of detail. But I'll expand the new release note, say This change partially reverts a performance improvement, introduced in version 10, that attempted to reduce the number of index pages locked during deletion of a GIN posting tree page. That's now been found to lead to deadlocks, so we've removed it pending closer analysis. regards, tom lane
