zulip/zerver/migrations/0444_userpresence_fill_data.py

72 lines
2.9 KiB
Python

from django.db import connection, migrations
from django.db.backends.base.schema import BaseDatabaseSchemaEditor
from django.db.migrations.state import StateApps
def fill_new_columns(apps: StateApps, schema_editor: BaseDatabaseSchemaEditor) -> None:
UserPresence = apps.get_model("zerver", "UserPresence")
# In theory, we'd like to preserve the distinction between the
# IDLE and ACTIVE statuses in legacy data. However, there is no
# correct way to do so; the previous data structure only stored
# the current IDLE/ACTIVE status of the last update for each
# (user, client) pair. There's no way to know whether the last
# time the user had the other status with that client was minutes
# or months beforehand.
#
# So the only sane thing we can do with this migration is to treat
# the last presence update as having been a PRESENCE_ACTIVE_STATUS
# event. This will result in some currently-idle users being
# incorrectly recorded as having been active at the last moment
# that they were idle before this migration. This error is
# unlikely to be significant in practice, and in any case is an
# unavoidable flaw caused by the legacy previous data model.
with connection.cursor() as cursor:
cursor.execute(
"SELECT realm_id, user_profile_id, MAX(timestamp) FROM zerver_userpresenceold WHERE status IN (1, 2) GROUP BY realm_id, user_profile_id"
)
latest_presence_per_user = cursor.fetchall()
UserPresence.objects.bulk_create(
[
UserPresence(
user_profile_id=presence_row[1],
realm_id=presence_row[0],
last_connected_time=presence_row[2],
last_active_time=presence_row[2],
)
for presence_row in latest_presence_per_user
],
# Limit the size of individual network requests for very large
# servers.
batch_size=10000,
# If the UserPresence worker has already started, or a user
# has changed their invisible status while migrations are
# running, then some UserPresence rows may exist. Those will
# generally be newer than what we have here, so ignoring
# conflicts so we can complete backfilling users who don't
# have more current data is the right resolution.
ignore_conflicts=True,
)
def clear_new_columns(apps: StateApps, schema_editor: BaseDatabaseSchemaEditor) -> None:
UserPresence = apps.get_model("zerver", "UserPresence")
UserPresence.objects.all().delete()
class Migration(migrations.Migration):
"""
Ports data from the UserPresence model into the new one.
"""
atomic = False
dependencies = [
("zerver", "0443_userpresence_new_table_schema"),
]
operations = [
migrations.RunPython(fill_new_columns, reverse_code=clear_new_columns, elidable=True)
]