connection was closed in the middle of operation

• asyncpg version: 0.15.0
• PostgreSQL version: 10.3
• local PostgreSQL:
• Python version: 3.6.5
• Platform: Ubuntu 14.04.5
• Do you use pgbouncer?: no
• Did you install asyncpg with pip?: yes

I use asyncpg with sanic. Before server start, a connection pool is made and attached to the app. In every route, the handler acquire a connection if pg access is needed. The problem is, if the pool is silent for too long, new acquired connection is not usable.

asyncpg.exceptions.ConnectionDoesNotExistError: connection was closed in the middle of operation

After one-time exception. The next acquisition is normal again. No exception with queries. Which is really weird for me.

I've tried to twist max_inactive_connection_lifetime parameter, got no luck. Actually I don't quite understand this parameter. Why would I need this parameter?

Any help is welcomed.

No source file or test is named. Start by reproducing the idle-pool scenario with asyncpg 0.15.0, PostgreSQL 10.3, Python 3.6.5, and Sanic, then inspect pool acquisition and the max_inactive_connection_lifetime behavior. Done means the cause of the first failed acquisition is identified and the behavior is verified after the relevant change.