mirror of https://github.com/zulip/zulip.git
54 lines
2.3 KiB
Python
54 lines
2.3 KiB
Python
# -*- coding: utf-8 -*-
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from django.db import migrations
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from django.db.backends.postgresql_psycopg2.schema import DatabaseSchemaEditor
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from django.db.migrations.state import StateApps
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from django.db.models import Count, Sum
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def clear_duplicate_counts(apps: StateApps, schema_editor: DatabaseSchemaEditor) -> None:
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"""This is a preparatory migration for our Analytics tables.
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The backstory is that Django's unique_together indexes do not properly
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handle the subgroup=None corner case (allowing duplicate rows that have a
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subgroup of None), which meant that in race conditions, rather than updating
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an existing row for the property/realm/time with subgroup=None, Django would
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create a duplicate row.
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In the next migration, we'll add a proper constraint to fix this bug, but
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we need to fix any existing problematic rows before we can add that constraint.
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We fix this in an appropriate fashion for each type of CountStat object; mainly
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this means deleting the extra rows, but for LoggingCountStat objects, we need to
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additionally combine the sums.
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"""
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RealmCount = apps.get_model('analytics', 'RealmCount')
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realm_counts = RealmCount.objects.filter(subgroup=None).values(
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'realm_id', 'property', 'end_time').annotate(
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Count('id'), Sum('value')).filter(id__count__gt=1)
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for realm_count in realm_counts:
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realm_count.pop('id__count')
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total_value = realm_count.pop('value__sum')
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duplicate_counts = list(RealmCount.objects.filter(**realm_count))
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first_count = duplicate_counts[0]
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if realm_count['property'] in ["invites_sent::day", "active_users_log:is_bot:day"]:
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# For LoggingCountStat objects, the right fix is to combine the totals;
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# for other CountStat objects, we expect the duplicates to have the same value.
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# And so all we need to do is delete them.
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first_count.value = total_value
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first_count.save()
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to_cleanup = duplicate_counts[1:]
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for duplicate_count in to_cleanup:
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duplicate_count.delete()
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class Migration(migrations.Migration):
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dependencies = [
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('analytics', '0014_remove_fillstate_last_modified'),
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]
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operations = [
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migrations.RunPython(clear_duplicate_counts,
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reverse_code=migrations.RunPython.noop),
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]
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