On Saturday, March 7, 2020, Dilip Kumar <dilipbal...@gmail.com> wrote:
> On Sat, Mar 7, 2020 at 9:59 AM Dilip Kumar <dilipbal...@gmail.com> wrote: > > > > On Sat, Mar 7, 2020 at 12:30 AM Andres Freund <and...@anarazel.de> > wrote: > > > > > > Hi, > > > > > > On 2020-01-08 18:06:52 +0530, Dilip Kumar wrote: > > > > On Wed, 8 Jan 2020 at 5:28 PM, Heikki Linnakangas <hlinn...@iki.fi> > wrote: > > > > > > > > > On 25/11/2019 05:52, Dilip Kumar wrote: > > > > > > In logical decoding, while sending the changes to the output > plugin we > > > > > > need to arrange them in the LSN order. But, if there is only one > > > > > > transaction which is a very common case then we can avoid > building the > > > > > > binary heap. A small patch is attached for the same. > > > > > > > > > > Does this make any measurable performance difference? Building a > > > > > one-element binary heap seems pretty cheap. > > > > > > > > > > > > I haven’t really measured the performance for this. I will try to > do that > > > > next week. Thanks for looking into this. > > > > > > Did you do that? > > > > I tried once in my local machine but could not produce consistent > > results. I will try this once again in the performance machine and > > report back. > > I have tried to decode changes for the 100,000 small transactions and > measured the time with head vs patch. I did not observe any > significant gain. > > Head > ------- > 519ms > 500ms > 487ms > 501ms > > patch > ------ > 501ms > 492ms > 486ms > 489ms > > IMHO, if we conclude that because there is no performance gain so we > don't want to add one extra path in the code then we might want to > remove that TODO from the code so that we don't spend time for > optimizing this in the future. > Would you be able to share your test setup? It seems like it’d helpful to get a larger sample size to better determine if it’s measurable or not. Visually those 4 runs look to me like it’s possible, but objectively I’m not sure we can yet conclude one way or the other. James
