On Mon, May 26, 2014 at 1:34 PM, Dmitry Samonenko <
shreddingwork@gmail.com> wrote:
> 1. Connection to PSQL server is made without an option to specify SO_RCVTIMEO and SO_SNDTIMEO. Why is that? Is setting socket timeouts considered harmful?
> 2. PQexec ultimately leads to PQwait, which after some function calls "lands" in pqSocketCheck and pqSocketPoll. These 2 functions have parameter end_time. It is set (-1) for PQexec scenario, which leads to infinite poll timeout in pqSocketPoll. Is it possible to implement configurable timeout for PQexec calls? Is there some implemented features, which should be used to handle situation like this?
Have you tried using Cancel functionality:
http://www.postgresql.org/docs/9.4/static/libpq-cancel.html> Currently, I have changed Linux kernel tcp4 stack counters responsible for retransmission, so OS actually closes socket after some period. This is detected by pqSocketPoll's poll and libpq handles situation correctly - error is reported to my application. But it's just a workaround.
There are certain tcp parameters which can be configured for connections.
tcp_keepalives_idle, tcp_keepalives_interval, tcp_keepalives_count