On Sun, Dec 13, 2009 at 5:42 AM, Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> wrote: > Walreceiver wants to wait for data to arrive from the master or a > signal. PQgetXLogData(), which is the libpq function to read a piece of > WAL, takes a timeout argument to support that. Walreceiver calls > PQgetXLogData() in an endless loop, checking for a received sighup or > death of postmaster at every iteration. > > In the synchronous replication mode, I presume it's also going to listen > for a signal from the startup process, so that it can send a > acknowledgment to the master as soon as a COMMIT record has been > replayed that a backend on the master is waiting for.
Right. > To implement the timeout in PQgetXLogData(), pqWaitTimed() was changed > to take a timeout instead of finishing_time argument. Which is a mistake > because it breaks PQconnectdb, and as I said I don't think > PQgetXLogData(9 should have a timeout argument to begin with. Instead, > it should have a boolean 'async' argument to return immediately if > there's no data, and walreceiver main loop should call poll()/select() > to wait. Ie. just like PQgetCopyData() works. Seems good. I'll revise the code. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
