On Sat, Apr 23, 2016 at 10:20:19AM -0400, Bruce Momjian wrote: > On Sat, Apr 23, 2016 at 12:48:08PM +0530, Amit Kapila wrote: > > On Sat, Apr 23, 2016 at 8:34 AM, Bruce Momjian <br...@momjian.us> wrote: > > > > > > I kind of agreed with Tom about just aborting transactions that held > > > snapshots for too long, and liked the idea this could be set per > > > session, but the idea that we abort only if a backend actually touches > > > the old data is very nice. I can see why the patch author worked hard > > > to do that.
As I understand it, a transaction trying to access a shared buffer aborts if there was a cleanup on the page that removed rows it might be interested in. How does this handle cases where vacuum removes _pages_ from the table? Does vacuum avoid this when there are running transactions? > Also, it seems we have similar behavior already in applying WAL on the > standby --- we delay WAL replay when there is a long-running > transaction. Once the time expires, we apply the WAL. Do we cancel the > long-running transaction at that time, or wait for the long-running > transaction to touch some WAL we just applied? If the former, does > Kevin's new code allow us to do the later? Is this a TODO item? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
