On Fri, Oct 20, 2023, at 8:08 AM, 'Tony Cosentini' via sqlalchemy wrote: > Hi, > > Is there any way to listen for an event for when a query result gets merged > into a pre-existing object in the session?
this is the refresh event: https://docs.sqlalchemy.org/en/20/orm/events.html#sqlalchemy.orm.InstanceEvents.refresh > > I'm working on disabling autoflush for some of our codebase (mostly to cut > down on queries on a high QPS path), but before doing that I want to write a > utility to detect when we read data that was flushed via autoflush to cut > down on any potential bugs. > > What I'd like to do is this (while autoflush is still enabled): > > table_one = TableOne(name='test') > session.add(table_one) # Track this object as pending a flush via the > before_* listeners, this is working as expected. > > table_two_instances = session.query(TableTwo).all() # All good, doesn't do > anything with the table_one instance created earlier > > table_one_instances = session.query(TableOne).all() # I would like to log a > warning here as the results of this query depend on a flush happening. What > I'm hoping to do is detect that one of the rows coming back is the same > object that was flagged earlier, but I can't see to find the correct event to > use. you probably want to also use refresh_flush also, which will be invoked for column defaults that are populated on the object https://docs.sqlalchemy.org/en/20/orm/events.html#sqlalchemy.orm.InstanceEvents.refresh_flush > > Is this possible? I can't seem to find the appropriate event that would > trigger when the results from the .all() query get merged back in with the > existing objects in the session. that's the refresh event -- 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/c5b89f67-e3fa-45f2-8774-463d154514f3%40app.fastmail.com.
