On Mon, Aug 14, 2023 at 8:38 PM shveta malik <shveta.ma...@gmail.com> wrote: > > On Mon, Aug 14, 2023 at 3:22 PM shveta malik <shveta.ma...@gmail.com> wrote: > > > > On Tue, Aug 8, 2023 at 11:11 AM Drouvot, Bertrand > > <bertranddrouvot...@gmail.com> wrote: > > > > > > Hi, > > > > > > On 8/8/23 7:01 AM, shveta malik wrote: > > > > On Mon, Aug 7, 2023 at 3:17 PM Drouvot, Bertrand > > > > <bertranddrouvot...@gmail.com> wrote: > > > >> > > > >> Hi, > > > >> > > > >> On 8/4/23 1:32 PM, shveta malik wrote: > > > >>> On Fri, Aug 4, 2023 at 2:44 PM Drouvot, Bertrand > > > >>> <bertranddrouvot...@gmail.com> wrote: > > > >>>> On 7/28/23 4:39 PM, Bharath Rupireddy wrote: > > > >> > > > > > > > > Agreed. That is why in v10,v11 patches, we have different infra for > > > > sync-slot worker i.e. it is not relying on "logical replication > > > > background worker" anymore. > > > > > > yeah saw that, looks like the right way to go to me. > > > > > > >> Maybe we should start some tests/benchmark with only one sync worker > > > >> to get numbers > > > >> and start from there? > > > > > > > > Yes, we can do that performance testing to figure out the difference > > > > between the two modes. I will try to get some statistics on this. > > > > > > > > > > Great, thanks! > > > > > > > We (myself and Ajin) performed the tests to compute the lag in standby > > slots as compared to primary slots with different number of slot-sync > > workers configured. > > > > 3 DBs were created, each with 30 tables and each table having one > > logical-pub/sub configured. So this made a total of 90 logical > > replication slots to be synced. Then the workload was run for aprox 10 > > mins. During this workload, at regular intervals, primary and standby > > slots' lsns were captured (from pg_replication_slots) and compared. At > > each capture, the intent was to know how much is each standby's slot > > lagging behind corresponding primary's slot by taking the distance > > between confirmed_flush_lsn of primary and standby slot. Then we took > > the average (integer value) of this distance over the span of 10 min > > workload and this is what we got: > > > > I have attached the scripts for schema-setup, running workload and > capturing lag. Please go through Readme for details. > > I did some more tests for 10,20 and 40 slots to calculate the average lsn distance between slots, comparing 1 worker and 3 workers.
My results are as follows: 10 slots 1 worker: 5529.75527426 (average lsn distance between primary and standby per slot) 3 worker: 2224.57589134 20 slots 1 worker: 9592.87234043 3 worker: 3194.62933333 40 slots 1 worker: 20566.0933333 3 worker: 7885.80952381 90 slots 1 worker: 36706.8405797 3 worker: 10236.6393162 regards, Ajin Cherian Fujitsu Australia