Files
zulip/zerver/migrations/0574_backfill_directmessagegroup_group_size.py
Mateusz Mandera 60e166bcd0 migrations: Fix migration 0574 to handle edge-case DirectMessageGroups.
The Django ORM query would not work correctly for pathological
DirectMessageGroups with no Subscription rows. When the Subquery gave
empty results, the UPDATE would set group_size to null - when the point
of the migration was exactly to make sure this column is always set and
allow making the column non-nullable in 0575.

Such DirectMessageGroups can occur as a result doing .delete() on all
UserProfiles that were in the group - or by doing realm deletion via
either .delete() or `manage.py delete_realm`.

The natural choice for group_size of these objects is 0. The simple SQL
query naturally achieves this result, without needing any special
handling for this case.
2025-03-25 10:30:27 -07:00

80 lines
2.5 KiB
Python

# Generated by Django 5.0.6 on 2024-08-16 06:44
from django.db import connection, migrations
from django.db.backends.base.schema import BaseDatabaseSchemaEditor
from django.db.migrations.state import StateApps
BATCH_SIZE = 1000
def backfill_group_size_field_for_direct_message_groups(
apps: StateApps, schema_editor: BaseDatabaseSchemaEditor
) -> None:
Recipient = apps.get_model("zerver", "Recipient")
RECIPIENT_DIRECT_MESSAGE_GROUP = 3
direct_message_group_recipient_entries = Recipient.objects.filter(
type=RECIPIENT_DIRECT_MESSAGE_GROUP
)
if not direct_message_group_recipient_entries.exists():
return
recipient_id_lower_bound = direct_message_group_recipient_entries.earliest("id").id
max_recipient_id = Recipient.objects.latest("id").id
# We would like to set the upper bound significantly past the
# maximum recipient id, because it is likely that new Direct
# Message Groups are created during this transaction, and their
# recipient id is assigned as the one right after the max id.
max_recipient_id += BATCH_SIZE
while recipient_id_lower_bound <= max_recipient_id:
do_backfill_group_size_field_for_direct_message_groups(
recipient_id_lower_bound,
min(recipient_id_lower_bound + BATCH_SIZE, max_recipient_id),
)
recipient_id_lower_bound += BATCH_SIZE + 1
def do_backfill_group_size_field_for_direct_message_groups(
recipient_id_lower_bound: int,
recipient_id_upper_bound: int,
) -> None:
with connection.cursor() as cursor:
update_query = """
UPDATE zerver_huddle
SET group_size = (
SELECT COUNT(*)
FROM zerver_subscription
WHERE zerver_subscription.recipient_id = zerver_huddle.recipient_id
)
WHERE zerver_huddle.recipient_id BETWEEN %(lower_bound)s AND %(upper_bound)s
AND zerver_huddle.group_size IS NULL
"""
cursor.execute(
update_query,
{
"lower_bound": recipient_id_lower_bound,
"upper_bound": recipient_id_upper_bound,
},
)
class Migration(migrations.Migration):
atomic = False
dependencies = [
("zerver", "0573_directmessagegroup_group_size"),
]
operations = [
migrations.RunPython(
backfill_group_size_field_for_direct_message_groups,
elidable=True,
reverse_code=migrations.RunPython.noop,
),
]