It occurred to my mind the fact that I forgot to mention the most significant outcome of this patch.
At Thu, 08 Oct 2020 16:03:26 +0900 (JST), Kyotaro Horiguchi <horikyota....@gmail.com> wrote in > At Tue, 06 Oct 2020 10:06:44 +0900 (JST), Kyotaro Horiguchi > <horikyota....@gmail.com> wrote in > > The previous version failed to flush local database stats for certain > > condition. That behavior caused useless retries and finally a forced > > flush that leads to contention. I fixed that and will measure > > performance with this version. > > I (we) got some performance numbers. > > - Fetching 1 tuple from 1 of 100 tables from 100 to 800 clients. > - Fetching 1 tuple from 1 of 10 tables from 100 to 800 clients. > > Those showed speed of over 400,000 TPS at maximum, and no siginificant > difference is seen between patched and unpatched at the all range of > the test. I tried 5 seconds as PGSTAT_MIN_INTERVAL (10s in the patch) > but that made no difference. > > - Fetching 1 tuple from 1 table from 800 clients. > > No graph for this is not attached but this test shows speed of over 42 > TPS with or without the v39 patch. Under a heavy load and having many tables, the *reader* side takes seconds ore more time to read the stats table. With this patch, it takes almost no time (maybe ms order?) for the same operation. regards. -- Kyotaro Horiguchi NTT Open Source Software Center
