I’m running into a problem where the connection between application its database is timing out after 12 hours.
Here’s the context:
· Two servers (one running the application and another hosting the database) in the Amazon AWS environment on different subnets within a virtual private cloud
· The server hosting the application is running Ubuntu 14.04.2 LTS
· The server hosting the database is running Ubuntu 14.04.2 LTS and PostgreSQL version 9.4.4
· An stunnel connection is provisioned from the client to the database. The app server is running stunnel version 4.53 with the following stunnel.conf settings:
; PID is created inside the chroot jail
pid = /stunnel4.pid
[postgres-<host>]
client = yes
protocol = pgsql
accept = 5432
connect = <host>:5432
options = NO_TICKET
retry = yes
· The database is provisioned to only accept “hostssl” type connections from the application server
I’ve enabled the logging of PostgreSQL connections and disconnections and I see that for connections that terminate before the associated query completes, the session time shown in the disconnect message is 12 hours plus three or four seconds.
I see this problem with both of the default tcp_keepalives settings of:
#tcp_keepalives_idle = 0
#tcp_keepalives_interval = 0
#tcp_keepalives_count = 0
And with the following settings:
tcp_keepalives_idle = 120
tcp_keepalives_interval = 120
tcp_keepalives_count = 5
I don’t see the disconnect problem for long-running queries that use a local database connection.
Any advice on what might be causing remote database connections to drop after 12 hours (and how to work around the issue)?
Kind regards,
Rich
