On Thu, Jul 25, 2024 at 4:00 PM Zhijie Hou (Fujitsu) <houzj.f...@fujitsu.com> wrote: > > When reviewing the code in logical/worker.c, I noticed that when applying a > cross-partition update action, it scans the old partition twice. > I am attaching the patch 0001 to remove this duplicate table scan. > > The test shows that it brings noticeable improvement: > > Steps > ----- > Pub: > create table tab (a int not null, b int); > alter table tab replica identity full; > insert into tab select 1,generate_series(1, 1000000, 1); > > Sub: > create table tab (a int not null, b int) partition by range (b); > create table tab_1 partition of tab for values from (minvalue) to (5000000); > create table tab_2 partition of tab for values from (5000000) to (maxvalue); > alter table tab replica identity full; > > > Test query: > update tab set b = 6000000 where b > 999900; -- UPDATE 100 > > Results (The time spent by apply worker to apply the all the UPDATEs): > Before 14s > After 7s > ----- >
The idea sounds good to me. BTW, we don't need the following comment in the 0001 patch: We + * don't call apply_handle_delete_internal() here to avoid + * repeating some work already done above to find the + * local tuple in the partition. It is implied by the change and we already follow the same for the update. -- With Regards, Amit Kapila.
