On Tue, Jun 8, 2021 at 10:28 AM Mike Bayer <mike...@zzzcomputing.com> wrote:
> > > > however, I would advise using pool_pre_ping instead which is much easier > to use and has basically no downsides. this feature didn't exist when > the docs for "optimistic disconnect" were written. > > > Sure. I was only looking at doing the optimistic disconnect because it > seemed a little more resilient to failures (if a DB error happens mid > transaction) and because I felt I could control the number of retries and > put in an exponential backoff. > > Do you suggest I use the custom pessimistic ping code: > > > https://docs.sqlalchemy.org/en/14/core/pooling.html#custom-legacy-pessimistic-ping > > to add in exponential backoff or add additional retries? > > > what's the real-world use case where exponential backoff is useful? > Unknown network failures, I suppose. I have an application that is throwing an exception right now due to: psycopg2.OperationalError: terminating connection due to administrator command SSL connection has been closed unexpectedly I don't know exactly what is causing the failure. Our VM guy seems to think it might be a network issue. Either way, I feel the code should retry a few times just to see if the cause of the error goes away. > do you expect databases to be shut down for a number of minutes without > disabling the application ? > No. I don't know what the timing parameters are of my particular failure. Pre ping doesn't seem like it allows for any sort of length of time before failing. I don't know if this offers any more clarity to what I'm experiencing and what I'm trying to code around. Thanks again for the help and dialogue! -m -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/CAOLfK3XEJWahpk9WRCNG%2BHkGGeiM7wR5zgmNeJHG2ECYkk%3Dc0A%40mail.gmail.com.
