On Thu, Sep 30, 2021 at 3:41 PM Kyotaro Horiguchi <horikyota....@gmail.com> wrote: > > At Thu, 30 Sep 2021 17:08:35 +0900 (JST), Kyotaro Horiguchi > <horikyota....@gmail.com> wrote in > > At Thu, 30 Sep 2021 17:21:03 +1000, Greg Nancarrow <gregn4...@gmail.com> > > wrote in > > > Actually, with the patch applied, I find that "make check-world" fails > > > (006_logical_decoding, test 7). > > > > Mmm.. > > > > t/006_logical_decoding.pl .. 4/14 > > # Failed test 'pg_recvlogical acknowledged changes' > > # at t/006_logical_decoding.pl line 117. > > # got: 'BEGIN > > # table public.decoding_test: INSERT: x[integer]:5 y[text]:'5'' > > # expected: '' > > > > I'm not sure what the test is checking for now, though. > > It's checking that endpos works correctly? The logical decoded WALs > looks like this. > > 0/1528F10|table public.decoding_test: INSERT: x[integer]:1 y[text]:'1' > 0/15290F8|table public.decoding_test: INSERT: x[integer]:2 y[text]:'2' > 0/1529138|table public.decoding_test: INSERT: x[integer]:3 y[text]:'3' > 0/1529178|table public.decoding_test: INSERT: x[integer]:4 y[text]:'4' > 0/15291E8|COMMIT 709 > 0/15291E8|BEGIN 710 > 0/15291E8|table public.decoding_test: INSERT: x[integer]:5 y[text]:'5' > 0/1529228|table public.decoding_test: INSERT: x[integer]:6 y[text]:'6' > > The COMMIT and BEGIN shares the same LSN, which I don't understand how come. >
This is because endlsn is always commit record + 1 which makes it equal to start of next record and we use endlsn here for commit. See below comments in code. /* * LSN pointing to the end of the commit record + 1. */ XLogRecPtr end_lsn; > The previous read by pg_recvlocal prceeded upto the COMMIT record. and > the following command runs after that behaves differently. > > pg_recvlogical -S test_slot --dbname postgres --endpos '0/15291E8' -f - > --no-loop --start > > Before the patch it ends before reading a record, and after the patch > it reads into the "table ..." line. pg_recvlogical seems using the > endpos as the beginning of the last record. In that meaning the three > lines (COMMIT 709/BEGIN 710/table ...'5') are falls under the end of > data. > > The difference seems coming from the timing keepalive > comes. pg_recvlogical checks the endpos only when keepalive comes. In > other words, it needs keepalive for every data line so that it stops > exactly at the specified endpos. > > 1. Is it the correct behavior that the three data lines share the same > LSN? I think BEGIN and the next line should do, but COMMIT and next > BEGIN shouldn't. > > 2. Is it the designed behavior that pg_recvlogical does check endpos > only when a keepalive comes? If it is the correct behavior, we > shouldn't avoid the keepalive flood. > If anything, I think this is a testcase issue as explained by me in email [1] [1] - https://www.postgresql.org/message-id/CAA4eK1Ja2XmK59Czv1V%2BtfOgU4mcFfDwTtTgO02Wd%3DrO02JbiQ%40mail.gmail.com -- With Regards, Amit Kapila.
