On Tue, Mar 22, 2016 at 6:29 PM, Andres Freund <andres@anarazel.de> wrote: > > On 2016-03-22 18:19:48 +0530, Amit Kapila wrote: > > > I'm actually rather unconvinced that it's all that common that all > > > subtransactions are on one page. If you have concurrency - otherwise > > > there'd be not much point in this patch - they'll usually be heavily > > > interleaved, no? You can argue that you don't care about subxacts, > > > because they're more often used in less concurrent scenarios, but if > > > that's the argument, it should actually be made. > > > > > > > Note, that we are doing it only when a transaction has less than equal to > > 64 sub transactions. > > So?
>
They should fall on one page, unless they are heavily interleaved as pointed by you. I think either subtransactions are present or not, this patch won't help for bigger transactions.
I will address your other review comments and send an updated patch.