Tom Lane wrote: > Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> writes: >> Changing the finish_time argument to pqWaitTimed into timeout_ms changes >> the behavior connect_timeout option to PQconnectdb. It should wait for >> max connect_timeout seconds in total, but now it is waiting for >> connect_timeout seconds at each step in the connection process: opening >> a socket, authenticating etc. > > Refresh my memory as to why this patch is touching any of that code at > all?
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. 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. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
