On Fri, Oct 20, 2023, at 10:46 AM, 'Tony Cosentini' via sqlalchemy wrote: > Oh I see, thanks for clarifying. > > I'm trying to detect cases where we depend on the autoflush behavior. For > example, in the sample above, when the query runs with no_autoflush, we won't > get back any results (when previously we would get back one row). It's a > fairly large codebase, so I was trying to automate finding these cases in > order to add explicit flush calls when needed or just pass in the pending > object instead of running a query.
there's not really an event for an object that just gets returned by a query from the identity map. you would need to do something more drastic like a do_orm_execute() hook that runs queries internally and then looks at all the returned objects. i wouldnt put that in production. > > Tony > > On Fri, Oct 20, 2023 at 10:42 PM Mike Bayer > <mike_not_on_goo...@zzzcomputing.com> wrote: >> __ >> >> >> On Fri, Oct 20, 2023, at 9:50 AM, 'Tony Cosentini' via sqlalchemy wrote: >>> Weird, I did try that but I can't seem to trigger it. >>> >>> Here's a self-contained test: >>> https://gist.github.com/tonycosentini/4dee3478695d032ca67707b5e26739b6 >> >> >> the object was not affected in that query (that is, not mutated). if you >> change the query to this: >> >> table_one_instances = session.query(TableOne).populate_existing().all() >> >> then the refresh event is triggered. >> >> Im not really following what kind of bug you are trying to detect. >> >> >>> >>> I have the event listener set to just crash, but it never triggers. >>> >>> On Fri, Oct 20, 2023 at 9:20 PM Mike Bayer >>> <mike_not_on_goo...@zzzcomputing.com> wrote: >>>> __ >>>> >>>> >>>> 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 a topic in the >>>> Google Groups "sqlalchemy" group. >>>> To unsubscribe from this topic, visit >>>> https://groups.google.com/d/topic/sqlalchemy/9bevy3Kpql4/unsubscribe. >>>> To unsubscribe from this group and all its topics, 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 >>>> >>>> <https://groups.google.com/d/msgid/sqlalchemy/c5b89f67-e3fa-45f2-8774-463d154514f3%40app.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/CAEx_o%2BAhhUSPDYuGL4TFkTvxjHYfKEWUnBMxh2PzCDw3GJPaGg%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/sqlalchemy/CAEx_o%2BAhhUSPDYuGL4TFkTvxjHYfKEWUnBMxh2PzCDw3GJPaGg%40mail.gmail.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 a topic in the >> Google Groups "sqlalchemy" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/sqlalchemy/9bevy3Kpql4/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> sqlalchemy+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/sqlalchemy/1047d2d1-6964-4d03-a978-dbac1b3e57ec%40app.fastmail.com >> >> <https://groups.google.com/d/msgid/sqlalchemy/1047d2d1-6964-4d03-a978-dbac1b3e57ec%40app.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. 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