mirror of
https://github.com/zulip/zulip.git
synced 2025-10-23 04:52:12 +00:00
aebc9081b8
These extended statistics allow the query planner to know that the prevalence of empty topics is very different in DMs, as opposed to channel messages. The `ALTER STATISTICS` adjusts the size of the "most common value" list -- it must be large enough to include the empty-topic channel messages to be fully effective. Having this list be over-large does not carry much risk, however. The `ANALYZE zerver_message` step may be quite slow.
22 lines
788 B
Python
22 lines
788 B
Python
from django.db import migrations
|
|
|
|
|
|
class Migration(migrations.Migration):
|
|
atomic = False
|
|
|
|
dependencies = [
|
|
("zerver", "0694_remove_message_unconditional_topic_indexes"),
|
|
]
|
|
|
|
operations = [
|
|
migrations.RunSQL(
|
|
sql="CREATE STATISTICS IF NOT EXISTS zerver_message_subject_is_channel_message ON subject, is_channel_message FROM zerver_message",
|
|
reverse_sql="DROP STATISTICS IF EXISTS zerver_message_subject_is_channel_message",
|
|
),
|
|
migrations.RunSQL(
|
|
sql="ALTER STATISTICS zerver_message_subject_is_channel_message SET STATISTICS 1500",
|
|
reverse_sql="ALTER STATISTICS zerver_message_subject_is_channel_message SET STATISTICS -1",
|
|
),
|
|
migrations.RunSQL("ANALYZE zerver_message"),
|
|
]
|