On Tue, 30 Nov 2021 at 12:19, Simon Riggs <simon.ri...@enterprisedb.com> wrote: > > On Mon, 30 Aug 2021 at 11:25, Andrey Borodin <x4...@yandex-team.ru> wrote: > > > > Hi Pengcheng! > > > > You are solving important problem, thank you! > > > > > 30 авг. 2021 г., в 13:43, Pengchengliu <pengcheng...@tju.edu.cn> > > > написал(а): > > > > > > To resolve this performance problem, we think about a solution which cache > > > SubtransSLRU to local cache. > > > First we can query parent transaction id from SubtransSLRU, and copy the > > > SLRU page to local cache page. > > > After that if we need query parent transaction id again, we can query it > > > from local cache directly. > > > > A copy of SLRU in each backend's cache can consume a lot of memory. > > Yes, copying the whole SLRU into local cache seems overkill. > > > Why create a copy if we can optimise shared representation of SLRU? > > transam.c uses a single item cache to prevent thrashing from repeated > lookups, which reduces problems with shared access to SLRUs. > multitrans.c also has similar. > > I notice that subtrans. doesn't have this, but could easily do so. > Patch attached, which seems separate to other attempts at tuning.
Re-attached, so that the CFapp isn't confused between the multiple patches on this thread. -- Simon Riggs http://www.EnterpriseDB.com/
subtrans_single_item_cache.v1.patch
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