I've spent some time thinking about what might be being asked here. the only thing I can think of is that when a particular database connection is found to be in what we call a "disconnect" state, the connection is invalidated, so that the connection will reconnect and make a new connection. But also, this operation will typically assume the "disconnect" condition is that the database was restarted, or some other network condition has probably made all the connections that are pooled also invalid. So the entire pool will be invalidated in this case as well.
Why someone might want to turn that off is if they are getting lots of invalidated connections for some other reason and they are not able to solve that problem, so they'd like the pool to not be invalidated totally. This means that if the database is restarted, and for example you have 20 pooled connections, you will in a high-request environment get up to 20 server errors unless pool_pre_ping is turned on so that the connections are refreshed one at at time. To disable the pool invalidation upon receipt of a single connection shown to be in a disconnect, implement the handle_error event: https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error and then set invalidate_pool_on_disconnect to False: https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect . On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote: > Im not sure if I understand the question? if you don't call .invalidate(), > then the connection is not invalidated. > > what does "turn off" mean ? > > > > On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote: >> Hi, >> >> Is there a way to safely turn off connection invalidation functionality >> (based on invalidation time set, all the connections created prior to the >> timestamp are invalidated) in sqlalchemy? >> >> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574 >> >> Thanks, >> Anupama >> >> >> -- >> 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/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com >> >> <https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > > -- > 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/a1807f9d-e0c4-4ee6-9c03-ff2a56afeded%40www.fastmail.com > > <https://groups.google.com/d/msgid/sqlalchemy/a1807f9d-e0c4-4ee6-9c03-ff2a56afeded%40www.fastmail.com?utm_medium=email&utm_source=footer>. -- 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/a9e2a459-7cc4-4bf9-bcff-6c0b3569549b%40www.fastmail.com.
