On Fri, May 6, 2016 at 5:23 PM, Vladimir Gordiychuk <fol...@gmail.com> wrote:
> Hi all, > > During implementing logical replication protocol for pgjdbc > https://github.com/pgjdbc/pgjdbc/pull/550 I faced with strange behavior > of the *walcender.c*: > > 1. When WAL consumer catchup master and change his state to streaming, > not available normally complete replication by send CopyDone message until > will not generate/create new WAL record. It occurs because logical decoding > located in *WalSndWaitForWal* until will not available next WAL > record, and it method receive message from consumer even reply on CopyDone > with CopyDone but ignore exit from loop and we can wait many times waiting > CommandStatus & ReadyForQuery packages on consumer. > 2. Logical decoding ignore message from consumer during decoding and > writing transaction in socket(*WalSndWriteData*). It affect long > transactions with many changes. Because for example if we start decoding > transaction that insert 1 million records and after consume 1% of it date > we > decide stop replication, it will be not available until whole million > record will not send to consumer. > > How exactly are you stopping the replication? If you just stop reading you'll likely to hit some problems, but what if you also close the connection? I don't think there is any other supported way to do it. I was working last year on adding support for replication protocol to the Python driver: https://github.com/psycopg/psycopg2/pull/322 It would be nice if you could skim through this implementation, since it didn't receive a whole lot of review. Cheers. -- Alex
