Jeff Janes <jeff.ja...@gmail.com> wrote: > On Fri, Sep 1, 2017 at 1:32 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: > > The "-r" option to pg_basebackup is supposed to throttle the rate of the > backup. But it only works properly if the server is mostly idle. > > Every non-trivial call to XLogFlush or XLogBackgroundFlush will wake up the > wal sender (the one which is not really sending wal, but base files), and > the throttling routine doesn't go back to sleep after being awoke > early. Rather, it releases another 32kb of data.
Sorry, I missed this fact when coding the feature. > Should the basebackup.c throttle sleep in a loop until its time has > expired? I think this is the correct approach because latch can be set for unrelated reasons. The patch makes sense to me. I just recommend moving this part in front of the loop because elapsed_min does not have to be re-computed each time: /* How much should have elapsed at minimum? */ elapsed_min = elapsed_min_unit * (throttling_counter / throttling_sample); And also a comment explaining the purpose of the loop would be appreciated. Thanks. -- Antonin Houska Cybertec Schönig & Schönig GmbH Gröhrmühlgasse 26 A-2700 Wiener Neustadt Web: http://www.postgresql-support.de, http://www.cybertec.at -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers