How to LOCK TABLE for PostgreSQL

[jens.t...@gmail.com]

Hello,

In order to use the PostgreSQL LOCK with SQLAlchemy, is there a better way than

session.execute(sa.text(f"LOCK TABLE {Foo.__tablename__} IN SHARE MODE"))

Poking through the dialect docs or SQLA at large, I didn’t find much. This post is a little dated, and this comment seems to recommend the above approach (using a connection).

Also, do I need to flush() to push the LOCK to the db?

Much thanks!

Jens

[Mike Bayer]

On Thu, Feb 23, 2023, at 10:44 PM, jens.t...@gmail.com wrote:

Hello,

In order to use the PostgreSQL LOCK with SQLAlchemy, is there a better way than

session.execute(sa.text(f"LOCK TABLE {Foo.__tablename__} IN SHARE MODE"))

I would probably use session.connection().exec_driver_sql() for more succinctness. 

if you want to build a custom SQL construct you can check out @compiles at https://docs.sqlalchemy.org/en/20/core/compiler.html

Also, do I need to flush() to push the LOCK to the db?

not at all, execute() as well as connection().execute(), connection().exec_driver_sql() push the given SQL right out, which you can see by adding echo=True to your create_engine().

Much thanks!

Jens

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