Set statement_timeout per connection or per transaction

Using peewee with postgres, you can normally set statement_timeout like this:

conn = PostgresqlExtDatabase(
    ...
    options='-c statement_timeout=1ms'
)

However, pgbouncer doesn’t allow options (you can ignore it, but it just doesn’t have effect then). So I’m planning to do something like:

database.connect()
database.execute_sql("SET statement_timeout = '1ms'")

This seems to work, but I wonder if it’s the correct approach(?)

Also, when you run pgbouncer in transaction mode, each transaction may get served a different connection. In this case, I think I should rather:

BEGIN
SET LOCAL statement_timeout = '1ms'
...

Is it possible to achieve this with peewee so that I wouldn’t need to manually do something like this:

with db.atomic():
    db.execute_sql('SET ...')

(transaction pooling mode is better than session mode because connections don’t lie idle when connection is open but no DB activity is happening.)

[coleifer]

This might also help: http://initd.org/psycopg/docs/usage.html#transactions-control

[coleifer]

This seems to work only when transaction is explicitly defined (e.g. with db.atomic()). It doesn’t trigger with autocommit=True.

Yes, that’s correct.

In the logs, I cannot see any BEGIN, COMMIT or SAVEPOINT messages so I’m not sure what db.atomic() actually triggers

The transactions are managed behind-the-scenes by psycopg2. You can see in the peewee code that it calls rollback() or commit() on the underlying psycopg2 connection object. The managing transactions document is worth reading if you’re unclear on Peewee’s APIs or how to use them.

Peewee always runs in autocommit mode by default. That is: Peewee will issue commit unless there is an active manual_commit or atomic block wrapping the code. If you want to explicitly manage transactions/commit yourself, you wrap the corresponding code in the manual_commit() context manager. If you want to wrap multiple operations in a transaction or savepoint, you wrap the corresponding code in an atomic() context manager. Otherwise each statement is effectively in its own transaction.