On Wed, Jul 8, 2020 at 7:28 AM David Rowley <dgrowle...@gmail.com> wrote: > > > I'd really like to see this thread move forward to a solution and I'm > not sure how best to do that. I started by reading back over both this > thread and the original one and tried to summarise what people have > suggested. >
Thanks, I think this might help us in reaching some form of consensus by seeing what most people prefer. > I understand some people did change their minds along the way, so I > may have made some mistakes. I could have assumed the latest mindset > overruled, but it was harder to determine that due to the thread being > split. > > For hash_mem = Justin [16], PeterG [15], Tomas [7] > hash_mem out of scope for PG13 = Bruce [8], Andres [9] > +1 for hash_mem out of scope for PG13. Apart from the reasons you have mentioned above, the other reason is if this is a way to allow users to get a smooth experience for hash aggregates, then I think the idea proposed by Robert is not yet ruled out and we should see which one is better. OTOH, if we want to see this as a way to give smooth experience for current use cases for hash aggregates and improve the situation for hash joins as well then I think this seems to be a new behavior which should be discussed for PG14. Having said that, I am not saying this is not a good idea but just I don't think we should pursue it for PG13. > Wait for reports from users = Amit [10] I think this is mostly inline with Bruce is intending to say ("Maybe do nothing until we see how things go during beta"). So, probably we can club the votes. > Escape hatch that can be removed later when we get something better = > Jeff [11], David [12], Pavel [13], Andres [14], Justin [1] > Add enable_hashagg_spill = Tom [2] (I'm unclear on this proposal. Does > it affect the planner or executor or both?) > Maybe do nothing until we see how things go during beta = Bruce [3] > Just let users set work_mem = Alvaro [4] (I think he changed his mind > after Andres pointed out that changes other nodes in the plan too) > Swap enable_hashagg for a GUC that specifies when spilling should > occur. -1 means work_mem = Robert [17], Amit [18] > hash_mem does not solve the problem = Tomas [6] > [1] - https://www.postgresql.org/message-id/ca+tgmobyv9+t-wjx-ctpdqurcgt1thz1ml3v1nxc4m4g-h6...@mail.gmail.com -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com