Asyncpg does not seem to clear memory allocated to Pool object after db.disconnect() (possible memory leak)

• asyncpg version: 0.25.0 (tried with 0.23.0 and 0.24.0)
• PostgreSQL version: 11.16
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No, using the postgres:11.16 docker image directrly
• Python version: 3.10.5 (+ latest 3.9 and 3.8)
• Platform: Ubuntu 64 and docker
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: N/A
• Can the issue be reproduced under both asyncio and
  uvloop?: I only tried asyncio

We observed PODs running out of memory.
They are reading from a queue constantly and calling this function

async def process_request(message, db : ):
    await db.connect()
    # do_something(message, db)
    await db.disconnect()

I am confident this is related to asyncpg as here are some of the objects that are created in memory with every iteration of connect/disconnect.

  asyncpg.pgproto.pgproto.ReadBuffer |        1000 |    132.81 KB
             collections.OrderedDict |        1000 |    125.00 KB
   asyncpg.pool.PoolConnectionHolder |        1000 |    117.19 KB
          asyncio.events.TimerHandle |        1001 |    109.48 KB

I have tried:

• waiting for the TimerHandle to expire (60s)
• calling engine.dispose() manually
• calling the garbage collector manually

Sometime in the past we encountered a problem that made 10000s of connections in a few seconds (crashing the DB) that was fixed by abandoning this connect/disconnect pattern, so maybe these two are related.

The db is initialised as such

databases.Database(db_uri)

This problem does not exists in the sqlite driver.

Commencez par reproduire le schéma répétitif db.connect() et db.disconnect() décrit avec asyncpg 0.25.0, PostgreSQL 11.16, Python 3.10.5 et l’image Docker postgres:11.16. Vérifiez si les objets asyncpg.pgproto.pgproto.ReadBuffer, OrderedDict, PoolConnectionHolder et asyncio.events.TimerHandle restent après la déconnexion et le garbage collection. Comparez le comportement avec le pilote sqlite et déterminez si les allocations conservées constituent une fuite.