SQLAlchemy before_update event with Postgres upserts

Question

I have a script that saves and updates data to a Postgres database using upserts:

        messageins = insert(Message).values(
            id = message.id,
            iserased = message.iserased,
            erasedby = eraserid,
            author = message.author.id,
            body = message.body,
            private = message.isprivate,
            created = convTime(message.timecreated),
            edited = convTime(message.timeedited),
            lobby = message.lobbyid,
            usermentions = message.mentions,
        )

        message_dict = {
            c.name: c
            for c in messageins.excluded
        }

        update_message = messageins.on_conflict_do_update(
            index_elements = ["id"],
            set_=message_dict
        )

        newdb.execute(update_message)

I'm trying to run a function on the before_update event:

def saveHistory(mapper, connect, target):
    historicaldata = dict(target)
    print("SaveHistory triggered\n")

event.listen(Message, 'before_insert', saveHistory)
event.listen(Message, 'before_update', saveHistory)

The saveHistory function isn't running. I see nothing in the documentation about Postgres-specific events. Are these event listeners supposed to work with the on_conflict_do_update() method?

HittingSmoke · Accepted Answer · 2018-10-26 15:19:16Z

1

Turns out Postgres upserts using insert() bypasses the ORM where the event hooks are. Using event hooks with this method of inserting data is not supported.

https://groups.google.com/forum/#!topic/sqlalchemy/Q1agVMU87_Q

answered Oct 26, 2018 at 15:19

HittingSmoke

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