background_drop_invalid_event_edges_rows failed

This issue has been migrated from [#16193](https://github.com/matrix-org/synapse/issues/16193).

---

### Description

Background update to drop invalid event edge rows failed.

### Steps to reproduce

- Start synapse

### Homeserver

tusooa.xyz

### Synapse Version

1.90.0

### Installation Method

Docker (matrixdotorg/synapse)

### Database

postgresql 13. single server. yes, used portdb. yes, once restored.

### Workers

Multiple workers

### Platform

Ubuntu 22.04, Kubernetes (4-node kubeadm cluster)

### Configuration

_No response_

### Relevant log output

```shell
2023-08-27 23:49:32,646 - synapse.storage.background_updates - 302 - ERROR - background_updates-0 - Error doing update
Traceback (most recent call last):
File "/usr/local/lib/python3.11/site-packages/synapse/storage/background_updates.py", line 294, in run_background_updates
result = await self.do_next_background_update(sleep)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/background_updates.py", line 424, in do_next_background_update
await self._do_background_update(desired_duration_ms)
File "/usr/local/lib/python3.11/site-packages/synapse/storage/background_updates.py", line 467, in _do_background_update
items_updated = await update_handler(progress, batch_size)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/databases/main/events_bg_updates.py", line 1408, in _background_drop_invalid_event_edges_rows
done = await self.db_pool.runInteraction(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 924, in runInteraction
return await delay_cancellation(_runInteraction())
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/internet/defer.py", line 1693, in _inlineCallbacks
result = context.run(
^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/python/failure.py", line 518, in throwExceptionIntoGenerator
return g.throw(self.type, self.value, self.tb)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 890, in _runInteraction
result = await self.runWithConnection(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 1019, in runWithConnection
return await make_deferred_yieldable(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/python/threadpool.py", line 244, in inContext
result = inContext.theWork() # type: ignore[attr-defined]
^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/python/threadpool.py", line 260, in
inContext.theWork = lambda: context.call( # type: ignore[attr-defined]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/python/context.py", line 117, in callWithContext
return self.currentContext().callWithContext(ctx, func, *args, **kw)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/python/context.py", line 82, in callWithContext
return func(*args, **kw)
^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/twisted/enterprise/adbapi.py", line 282, in _runWithConnection
result = func(conn, *args, **kw)
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 1012, in inner_func
return func(db_conn, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 752, in new_transaction
r = func(cursor, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/synapse/storage/databases/main/events_bg_updates.py", line 1403, in drop_invalid_event_edges_txn
txn.execute(
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 417, in execute
self._do_execute(self.txn.execute, sql, parameters)
File "/usr/local/lib/python3.11/site-packages/synapse/storage/database.py", line 469, in _do_execute
return func(sql, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^
psycopg2.errors.ForeignKeyViolation: insert or update on table "event_edges" violates foreign key constraint "event_edges_event_id_fkey"
DETAIL: Key (event_id)=($ukE7gZZjUyJ6AWo3j-yziYIwtm5QBWh4_V-AwoChtqs) is not present in table "events".
```

### Anything else that would be useful to know?

_No response_