From: pgsql-hackers-ow...@postgresql.org > [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Tsunakawa, > Takayuki > I found a wrong sentence here in the doc. I'm sorry, this is what I asked > you to add... > > https://www.postgresql.org/docs/devel/static/libpq-connect.html#libpq- > paramkeywords > > connect_timeout > Maximum wait for connection, in seconds (write as a decimal integer string). > Zero or not specified means wait indefinitely. It is not recommended to > use a timeout of less than 2 seconds. This timeout applies separately to > each connection attempt. For example, if you specify two hosts and both > of them are unreachable, and connect_timeout is 5, the total time spent > waiting for a connection might be up to 10 seconds. > > > The program behavior is that libpq times out after connect_timeout seconds > regardless of how many hosts are specified. I confirmed it like this: > > $ export PGOPTIONS="-c post_auth_delay=30" > $ psql -d "dbname=postgres connect_timeout=5" -h localhost,localhost -p > 5432,5433 > (psql erros out after 5 seconds) > > Could you fix the doc with something like this? > > "This timeout applies across all the connection attempts. For example, if > you specify two hosts and both of them are unreachable, and connect_timeout > is 5, the total time spent waiting for a connection is up to 5 seconds." > > Should we also change the minimum "2 seconds" part to be longer, according > to the number of hosts?
Instead, I think we should fix the program to match the documented behavior. Otherwise, if the first database machine is down, libpq might wait for about 2 hours (depending on the OS's TCP keepalive setting), during which it tims out after connect_timeout and does not attempt to connect to other hosts. I'll add this item in the PostgreSQL 10 Open Items. Regards Takayuki Tsunakawa -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
