Migrate all `ids` of anything which does not have a foreign key from
the Message or UserMessage table (and would thus require walking
those) to be `bigint`. This is done by removing explicit
`BigAutoField`s, trading them for explicit `AutoField`s on the tables
to not be migrated, while updating `DEFAULT_AUTO_FIELD` to the new
default.
In general, the tables adjusted in this commit are small tables -- at
least compared to Messages and UserMessages.
Many-to-many tables without their own model class are adjusted by a
custom Operation, since they do not automatically pick up migrations
when `DEFAULT_AUTO_FIELD` changes[^1].
Note that this does multiple scans over tables to update foreign
keys[^2]. Large installs may wish to hand-optimize this using the
output of `./manage.py sqlmigrate` to join multiple `ALTER TABLE`
statements into one, to speed up the migration. This is unfortunately
not possible to do generically, as constraint names may differ between
installations.
This leaves the following primary keys as non-`bigint`:
- `auth_group.id`
- `auth_group_permissions.id`
- `auth_permission.id`
- `django_content_type.id`
- `django_migrations.id`
- `otp_static_staticdevice.id`
- `otp_static_statictoken.id`
- `otp_totp_totpdevice.id`
- `two_factor_phonedevice.id`
- `zerver_archivedmessage.id`
- `zerver_client.id`
- `zerver_message.id`
- `zerver_realm.id`
- `zerver_recipient.id`
- `zerver_userprofile.id`
[^1]: https://code.djangoproject.com/ticket/32674
[^2]: https://code.djangoproject.com/ticket/24203
Previously, when the operand of id operator was more than
2147483647, it was raising server error. This is because the
maximum permissible PostgreSQL integers value is 2147483647.
This is fixed by raising a BadNarrowOperatorError in case the
id operand is larger than 2147483647.
For endpoints with a type parameter to indicate whether a message is
a direct or stream message, adds support for passing "channel" as a
value for stream messages.
Part of stream to channel rename project.
Calling `.select_related()` with no arguments joins through every
possible table, recursively. In this case, this currently produces a
query which joins through forty-three tables.
This is rather inefficient, particularly for what is a very common
call which should be very fast.
No callsite depends on having prefetched any joined table on the
object; drop all of the joins.
By default, `SELECT FOR UPDATE` will also lock any rows which are
`JOIN`ed into the selected rows; in the case of UserMessage rows, this
can mean arbitrary Message rows.
Since the messages themselves are not being changed, it is not
necessary to lock them -- and doing so may lead to deadlocks, in the
case that the UserMessage row is locked for update before the Message,
and some other request has already taken a read lock on the Message
and is blocked on the UserMessage write lock.
Change `select_for_update_query` to explicitly only lock UserMessage.
Alex Vandiver
roanster007
Mateusz Mandera
Lauryn Menard
Anders Kaseorg