Add this field to the Stream model will prevent us from having
to look at realm data for several types of stream operations, which
can be prone to either doing extra database lookups or making
our cached data bloated.
Going forward, we'll set stream.is_zephyr to True whenever the
realm's string id is "zephyr".
Since subscribed_to_stream is only doing an id lookup
on the Stream model to find out if a user is subscribed to
a stream, there's no reason to require a full Stream object.
It's currently the case that all callers do have full Stream
objects handy to pass in to this function, but it's still a
good practice to have functions only ask for objects that they
need.
We now return user_ids for subscribers to streams in add-stream
events. This allows us to eliminate the UserLite class for
both bulk adds and bulk removes. It also simplifies some JS
code that already wanted to use user_ids, not emails.
Fixes#6898
Using lightweight objects will speed up adding new users
to realms.
We also sort the query results, which lets us itertools.groupby
to more efficiently build the data structure.
Profiling on a large data set shows about a 25x speedup for this
function, and before the optimization, this function accounts
for most of the time spend in bulk_add_subscriptions.
There's a lot less memory to allocate. I didn't measure
the memory difference.
When we test-deployed this to chat.zulip.org, we got about a 6x
speedup.
We now do push notifications and missed message emails
for offline users who are subscribed to the stream for
a message that has been edited, but we short circuit
the offline-notification logic for any user who presumably
would have already received a notification on the original
message.
This effectively boils down to sending notifications to newly
mentioned users. The motivating use case here is that you
forget to mention somebody in a message, and then you edit
the message to mention the person. If they are offline, they
will now get pushed notifications and missed message emails,
with some minor caveats.
We try to mostly use the same techniques here as the
send-message code path, and we share common code with the
send-message path once we get to the Tornado layer and call
maybe_enqueue_notifications.
The major places where we differ are in a function called
maybe_enqueue_notifications_for_message_update, and the top
of that function short circuits a bunch of cases where we
can mostly assume that the original message had an offline
notification.
We can expect a couple changes in the future:
* Requirements may change here, and it might make sense
to send offline notifications on the update side even
in circumstances where the original message had a
notification.
* We may track more notifications in a DB model, which
may simplify our short-circuit logic.
In the view/action layer, we already had two separate codepaths
for send-message and update-message, but this mostly echoes
what the send-message path does in terms of collecting data
about recipients.
Postgres doesn't like them, we don't have an obvious way to escape
them, and they tend to be sent by buggy tools where it'd be better for
the user to get an error.
This fixes a 500 we were getting occasionally.
We have two different concepts of "idle", and this function
is based on the "presence" aspect of idleness. There is also
idleness in terms of a user having no current client
descriptors accepting messages, and we check that later in
the process for things like sending missed message emails.
check_send_stream_message is a simpler version of
check_send_message for sending messages where the addressee is
a stream. Instead of relying on Addressee.legacy_build,
check_send_stream_message uses Addressee.for_stream. Consequently,
it eschews many of check_send_message's kwargs that aren't needed
when the intended recipient of a message is a stream.
Having Addressee take care of setting stream_name to
sender.default_sending_stream.name makes us able to have
the invariant that stream_name is never None when the
message type is 'stream', which will help for mypy, among
other things.
One thing to be aware of is that Addressee does do a little
bit of validation work, and this adds yet another JsonableError
exception. I don't view this as a bad thing, just something to
know.
The dictionary result for get_user_info_for_message_updates()
now has a `mention_user_ids` field that is a set of user ids
who were mentioned in a message.
There are several reasons to extract this function:
* It's easy to unit test without extensive mocking.
* It will show up when we profile code.
* It is something that you can mostly ignore for
most messages.
The main reason to extract this, though, is that we are about
to do some fairly complex splicing of data for the use case
of mentioning service bots on streams they are not subscribed to,
and we want to localize the complexity.
This fixes a bug where the internal_prep_message code path would
incorrectly ignore the `realm` that was passed into it. As a result,
attempts to send messages using the system bots with this code path
would crash.
As a sidenote, we really need to make our test system consistent with
production in terms of whether the user's realm is the same as the
system realm.
We don't access any attributes of the sender other than the realm, and
as it turns out, we in some cases want to use a different realm than
the sender's.
Previously, invitation reminder emails were only being cleared after a
successful signup if newsletter_data was available, since that was the
circumstance in which we were calling the relevant queue processor
code. Now, we (1) clear them when a human user finishes signing up
and (2) correctly clear them using the 'address' field of
ScheduleEmail, not user_id.
We don't need full Realm objects to find DefaultStream
objects for a realm. So now a few functions related to
adding/removing default streams use realm_id for lookups.
Similarly, we don't need a full Stream object to find
out if a stream exists in DefaultStream, so we do id
lookups there as well.
This sets us up to use thinner objects in callers.
We now have a dedicated cache for active_user_ids() that only
stores a list of user_ids.
Before this commit, active_user_ids() used a cache of UserProfile
dictionaries, so it incurred unnecessary deserialization costs for
all the user fields that it sliced away in a list comprehension.
Because the cache is skinnier here, we also need to invalidate it
less frequently. Basically, all we care about is new users, realm
deactivations, and user deactivations.
It's hard to measure how much this will improve performance, because
the speedup for any operation here is pretty minor, but we use this
function a lot, so hopefully it will make the overall system more
healthy.
This is mostly a preparatory commit for an upcoming optimization
related to stream data, but it probably does save us an
occasional DB hop to the realm table.
