Alembic migration fails with enable statement_cache_size

[sc0rp10]

Hello!

Recently we've installed PgDog and have been trying to test it with our workload. Now we're stuck on a broken Alembic migration that prevents application startup. Once we enable prepared statements, the crash appears, so it looks like this bug is somehow connected to PgDog and prepared statements.

It returns a somewhat strange message that doesn't correspond to reality. The desired record exists in the alembic_version table, so it looks completely strange.

A bit more details:

traceback

ERROR:    Traceback (most recent call last):
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/base.py", line 213, in _catch_revision_errors
    yield
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/base.py", line 421, in _upgrade_revs
    for script in reversed(list(revs))
                           ~~~~^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 814, in iterate_revisions
    revisions, heads = fn(
                       ~~^
        upper,
        ^^^^^^
    ...<3 lines>...
        assert_relative_length=assert_relative_length,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 1475, in _collect_upgrade_revisions
    current_revisions = self.get_revisions(lower)
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 542, in get_revisions
    return sum([self.get_revisions(id_elem) for id_elem in id_], ())
                ~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 565, in get_revisions
    return tuple(
        self._revision_for_ident(rev_id, branch_label)
        for rev_id in resolved_id
    )
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 566, in <genexpr>
    self._revision_for_ident(rev_id, branch_label)
    ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/app/.venv/lib/python3.13/site-packages/alembic/script/revision.py", line 637, in _revision_for_ident
    raise ResolutionError(
    ...<11 lines>...
    )
alembic.script.revision.ResolutionError: No such revision or branch '005_add_service_environments'

The sqlalchemy configuration is deadly simple

config

from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

from src.config import settings

# Create async engine with connection pooling
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=False,
    pool_size=10,
    max_overflow=20,
    connect_args={"statement_cache_size": 100}, # <<< setting this value greater than 0 breaks everything
)

pgdog.toml

[general]
host = "0.0.0.0"
port = 5432
pooler_mode = "transaction"
default_pool_size = 5
openmetrics_port = 9187

[[databases]]
name = "foo"
host = "postgres-misc.foo.svc.cluster.local"
port = 5432
database_name = "foo"
role = "primary"

[levkk]

Hey! Not obvious what's happening here immediately. Would you be able to share trace logs of the event?

export RUST_LOG=trace

And run pgdog again. This is only safe to do in local/CI, not prod, since this generates a lot of logs.