From 9b779611f9bafd6c0affafda9732cecdb8efa761 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Tue, 17 Nov 2020 17:13:24 -0500 Subject: Support pool.connect() event firing before all else Fixed regression where a connection pool event specified with a keyword, most notably ``insert=True``, would be lost when the event were set up. This would prevent startup events that need to fire before dialect-level events from working correctly. The internal mechanics of the engine connection routine has been altered such that it's now guaranteed that a user-defined event handler for the :meth:`_pool.PoolEvents.connect` handler, when established using ``insert=True``, will allow an event handler to run that is definitely invoked **before** any dialect-specific initialization starts up, most notably when it does things like detect default schema name. Previously, this would occur in most cases but not unconditionally. A new example is added to the schema documentation illustrating how to establish the "default schema name" within an on-connect event (upcoming as part of I882edd5bbe06ee5b4d0a9c148854a57b2bcd4741) Addiional changes to support setting default schema name: The Oracle dialect now uses ``select sys_context( 'userenv', 'current_schema' ) from dual`` to get the default schema name, rather than ``SELECT USER FROM DUAL``, to accommodate for changes to the session-local schema name under Oracle. Added a read/write ``.autocommit`` attribute to the DBAPI-adaptation layer for the asyncpg dialect. This so that when working with DBAPI-specific schemes that need to use "autocommit" directly with the DBAPI connection, the same ``.autocommit`` attribute which works with both psycopg2 as well as pg8000 is available. Fixes: #5716 Fixes: #5708 Change-Id: I7dce56b4345ffc720e25e2aaccb7e42bb29e5671 --- lib/sqlalchemy/engine/create.py | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'lib/sqlalchemy/engine') diff --git a/lib/sqlalchemy/engine/create.py b/lib/sqlalchemy/engine/create.py index 7f5b5e8f5..786f8f5d6 100644 --- a/lib/sqlalchemy/engine/create.py +++ b/lib/sqlalchemy/engine/create.py @@ -657,17 +657,14 @@ def create_engine(url, **kwargs): dialect.initialize(c) dialect.do_rollback(c.connection) - if do_on_connect: - event.listen( - pool, "connect", first_connect, _once_unless_exception=True - ) - else: - event.listen( - pool, - "first_connect", - first_connect, - _once_unless_exception=True, - ) + # previously, the "first_connect" event was used here, which was then + # scaled back if the "on_connect" handler were present. now, + # since "on_connect" is virtually always present, just use + # "connect" event with once_unless_exception in all cases so that + # the connection event flow is consistent in all cases. + event.listen( + pool, "connect", first_connect, _once_unless_exception=True + ) dialect_cls.engine_created(engine) if entrypoint is not dialect_cls: -- cgit v1.2.1