On Tue, Dec 6, 2022 at 7:18 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Tue, Dec 6, 2022 at 7:29 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > On Tue, Dec 6, 2022 at 11:53 AM shiy.f...@fujitsu.com > > <shiy.f...@fujitsu.com> wrote: > > > > > > Hi hackers, > > > > > > In logical decoding, when logical_decoding_work_mem is exceeded, the > > > changes are > > > sent to output plugin in streaming mode. But there is a restriction that > > > the > > > minimum value of logical_decoding_work_mem is 64kB. I tried to add a GUC > > > to > > > allow sending every change to output plugin without waiting until > > > logical_decoding_work_mem is exceeded. > > > > > > This helps to test streaming mode. For example, to test "Avoid streaming > > > the > > > transaction which are skipped" [1], it needs many XLOG_XACT_INVALIDATIONS > > > messages. With the new option, it can be tested with fewer changes and in > > > less > > > time. Also, this new option helps to test more scenarios for "Perform > > > streaming > > > logical transactions by background workers" [2]. > > > > > > > Yeah, I think this can also help in reducing the time for various > > tests in test_decoding/stream and > > src/test/subscription/t/*_stream_*.pl file by reducing the number of > > changes required to invoke streaming mode. > > +1 > > > Can we think of making this > > GUC extendible to even test more options on server-side (publisher) > > and client-side (subscriber) cases? For example, we can have something > > like logical_replication_mode with the following valid values: (a) > > server_serialize: this will serialize each change to file on > > publishers and then on commit restore and send all changes; (b) > > server_stream: this will stream each change as currently proposed in > > your patch. Then if we want to extend it for subscriber-side testing > > then we can introduce new options like client_serialize for the case > > being discussed in the email [1]. > > Setting logical_replication_mode = 'client_serialize' implies that the > publisher behaves as server_stream? or do you mean we can set like > logical_replication_mode = 'server_stream, client_serialize'? >
The latter one (logical_replication_mode = 'server_stream, client_serialize'). The idea is to cover more options with one GUC and each option can be used individually as well as in combination with others. -- With Regards, Amit Kapila.
