On Thu, May 27, 2021 at 9:43 AM Amit Kapila <amit.kapil...@gmail.com> wrote: > > I have read it but I think we should try to ensure practically what is > > happening because it is possible that first time worker checked in FSM > > without taking relation extension lock, it didn't find any free page, > > and then when it tried to acquire the conditional lock, it got the > > same and just extended the relation by one block. So, in such a case > > it won't be able to use the newly added pages by another worker. I am > > not sure any such thing is happening here but I think it is better to > > verify it in some way. Also, I am not sure if just getting the info > > about the relation extension lock is sufficient? > > > > One idea to find this out could be that we have three counters for > each worker which counts the number of times each worker extended the > relation in bulk, the number of times each worker extended the > relation by one block, the number of times each worker gets the page > from FSM. It might be possible that with this we will be able to > figure out why there is a difference between your and Hou-San's > results.
Yeah, that helps. And also, the time spent in LockRelationForExtension, ConditionalLockRelationForExtension, GetPageWithFreeSpace and RelationAddExtraBlocks too can give some insight. My plan is to have a patch with above info added in (which I will share it here so that others can test and see the results too) and run the "case 4" where there's a regression seen on my system. With Regards, Bharath Rupireddy. EnterpriseDB: http://www.enterprisedb.com
