pubsub listen with a timeout?

[Matt Billenstein]

the blocking list functions support a timeout parameter, but pubsub listen does not - this would seem to be necessary for implementing things like longpolling.  Is anyone else missing this functionality or is it just me?

m

[Josiah Carlson]

It would be useful, yes.

On the other hand, if you send a heartbeat down your pubsub channels,
you can implement timeouts on the client side without much difficulty.
Then again, I advocate for not using pubsub at all, and instead
advocate using polling itself unless you absolutely must get as close
to real-time performance as possible.

Regards,
- Josiah

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[Matt Billenstein]

In this case the latency matters since the user takes an action in one place and is waiting to see something update in another place -- why do you advocate polling instead of pubsub?  pubsub or blocking list pops seem like the most efficient way to go about things like this.

m

[Josiah Carlson]

Slow clients, too many clients, spotty network, etc., can cause
outgoing buffers to grow, Redis memory use to grow, potentially
causing a hang and/or crash.

If everyone polls, then on such a situation, some people slow down,
but the system is still available, because no one can poll more than
they receive.

If you are using Redis pubsub as a point-to-point messaging setup,
it's probably not an issue unless you are moving many millions of
messages per day. We ran into a shoddy network card/switch in EC2
leading to memory growth and a crash on a master. For us, it happened
pretty fast because of our volume of writes (which was good for us).
In pubsub, you may see slow memory growth over time, or never see it
(except that you have things completing on one side, but not being
reported on the other), or you may not even get your requested timeout
response (if your feature request is accepted and implemented) from
Redis.

Regards,
- Josiah

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[Jacky Fang]

在 2011年9月8日星期四 UTC+8上午4:14:58，Matt Billenstein写道：

the blocking list functions support a timeout parameter, but pubsub listen does not - this would seem to be necessary for implementing things like longpolling.  Is anyone else missing this functionality or is it just me?

m

Is this problem solved?