test_migration_timeout_on_sync

[BagritsevichStepan]

test_migration_timeout_on_sync fails:
https://github.com/dragonflydb/dragonfly/actions/runs/14072766269/job/39410208905

[BorysTheDev]

Problem: Migrations are marked as finished before we update the configuration.

[BorysTheDev]

Options:

1. update config during Pause() and then mark migration as finished (updating config has mutexes lock competing with DFLYCLUSTER CONFIG command, so it's dangerous with current implementation)
2. Mark migration as finished after the config update operation can create data loss because it will happen after Pause()
3. Wait for mutex removing refactoring in cluster config update operation and update config during Pause()

[adiholden]

I am trying to understand the problem, we are updating the migration status during pause but updating the slots config after we finish pause? If the answer is yes this can lead to dataloss

[BorysTheDev]

I am trying to understand the problem, we are updating the migration status during pause but updating the slots config after we finish pause? If the answer is yes this can lead to dataloss

Yes it's correct

[adiholden]

After sync with Borys he agrees that we do pause non admin connection also at the time we apply the config.
Therefore the get in the test should paused until config is updated
with pytest.raises(aioredis.ResponseError) as e_info:
await nodes[0].client.get("x")
Borys will continue to investigate this

[romange]

Failed again for me:
https://github.com/dragonflydb/dragonfly/actions/runs/14381541246/job/40326315258?pr=4910#step:12:1193

[abhijat]

seems to fail with a different signature:

https://github.com/dragonflydb/dragonfly/actions/runs/14429316882/job/40462198320#step:6:1067

E               AssertionError: [['out', '18bc5dfab9fdf19e12c486a7c7bd5b05d459b260', 'SYNC', 299950, '0']]
E               assert (1 != 0 and False)
E                +  where 1 = len([['out', '18bc5dfab9fdf19e12c486a7c7bd5b05d459b260', 'SYNC', 299950, '0']])
E                +  and   False = all(<generator object wait_for_error.<locals>.<genexpr> at 0x7f3e31b11ac0>)