On Fri, 14 Apr 2023 13:21:05 +0200 Matthias van de Meent <boekewurm+postg...@gmail.com> wrote:
> On Fri, 14 Apr 2023 at 12:59, Konstantin Knizhnik <knizh...@garret.ru> wrote: > > > > Hi hackers, > > > > Too small value of work_mem cause memory overflow in parallel hash join > > because of too much number batches. > > There is the plan: > > [...] > > > There is still some gap between size reported by memory context sump and > > actual size of backend. > > But is seems to be obvious, that trying to fit in work_mem > > sharedtuplestore creates so much batches, that them consume much more > > memory than work_mem. Indeed. The memory consumed by batches is not accounted and the consumption reported in explain analyze is wrong. Would you be able to test the latest patchset posted [1] ? This does not fix the work_mem overflow, but it helps to keep the number of batches balanced and acceptable. Any feedback, comment or review would be useful. [1] https://www.postgresql.org/message-id/flat/20230408020119.32a0841b%40karst#616c1f41fcc10e8f89d41e8e5693618c Regards,
