Hi, Fujii Masao wrote: > One of the major complaints about the current synch rep patch is that > signals are used for communication between backends and walsender. > On some platforms, a signal doesn't interrupt sleep (i.e. poll or select > system call), which would increase the performance overhead of > replication.
Reading the past messages on this topic, I realized that this problem so far only affects HPUX. I fear the proposed UDP/semaphores approach might have a similar gotcha on at least one of the supported platforms, too. Limits of open file descriptors come to mind, for example. Or kernel packet filtering rules, as mentioned in pgstat.c. If I understand correctly, even Postgres itself suffers from that problem on HPUX (even though the consequences aren't dramatic, as pointed out by Tom). Plus we are not completely save from syscalls returning EINTR due to SA_RESTART not being set for SIGALRM. So, does it really make sense to take care of this issue as part of the sync rep patch? Regards Markus Wanner -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
