On Tue, May 12, 2015 at 12:29:56AM +0300, Heikki Linnakangas wrote: > On 05/12/2015 12:00 AM, Bruce Momjian wrote: > >Multi-xacts were made durable in Postgres 9.3 (released 2013-09-09) to > >allow primary-key-column-only locks. 1.7 years later, we are still > >dealing with bugs related to this feature. Obviously, something is > >wrong. > > > >There were many 9.3 minor releases containing multi-xacts fixes, and > >these fixes have extended into 9.4. After the first few bug-fix > >releases, I questioned whether we needed to revert or rework the > >feature, but got no positive response. Only in the past few weeks have > >we got additional people involved. > > The "revert or rework" ship had already sailed at that point. I
True. > don't think we had much choice than just soldier through the bugs > after the release. The problem is we "soldiered on" without adding any resources to the problem or doing a systematic review once it became clear one was necessary. > >I think we now know that our inaction didn't serve us well. The > >question is how can we identify chronic problems and get resources > >involved sooner. I feel we have been "asleep at the wheel" to some > >extent on this. > > Yeah. I think the problem was that no-one realized that this was a > significant change to the on-disk format. It was deceptively > backwards-compatible. When it comes to permanent on-disk structures, > we should all be more vigilant in the review. Yes, and the size/age of the patch helped mask problems too. Are these the lessons we need to learn? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers