Slider callback_policy should work for apps

[bryevdv]

Currently callback_policy only affects the triggering of JS callbacks, but it would be extremely useful to be able to throttle callbacks triggered on the server as well. It's possible that throttle mode is not very consistent with this, we might have to interpret throttle as mouseup for purposes of rate-limiting server updates.

[bill10]

+1 for this. I will be looking forward to this as I am running some expensive calculation.

[crashMOGWAI]

👍 Just ran into this issue while working with the server and trying to filter large data sets via the sliders.

[bryevdv]

There's a workable solution on stack overflow. Apologies, I can find it on a phone.

[crashMOGWAI]

If anyone else finds this issue:
http://stackoverflow.com/questions/38375961/throttling-in-bokeh-application

[sandipde]

Just ran into this issue. Is there any workaround for this. I want to have the slide.on_change event to occur at 'mouseup'.

[w4nderlust]

+1
Adding on_mouseup or something similar to sliders would be much appreciated, at the moment the on_change function is called more often than it can be computed in my project too.

[bryevdv]

There is a serviceable workaround in the StackOverflow answer linked above

[w4nderlust]

@bryevdv thanks for pointing it out. I actually found it before this issue thread, and I consider it an ugly hack rather than a workaround :)

[bryevdv]

@w4nderlust that sort of comment is neither useful nor appreciated. There is currently more work than people to do it, so if you can do better, great, pull requests are welcome.

[w4nderlust]

@bryevdv didn’t meant to offend anyone, sorry. My point was that I saw that before commenting on this thread and decided not to include it in my codebase, so having a working workaround didn’t really solve it for me (and doesn’t really solve the problem in general). I’ll gladly contribute if this was a python issue, unfortunately it is mostly a js callback one and on that side I can’t really help. No harm intended anyway, sorry again.

[bryevdv]

I think there is actually a simple solution that could work, namely adding a new value_throttled property, that is only updated on the JS side according to the throttle policy. Then if users want throttles response they can perform slider.on_change('value_throttled', ...). This does place a slight burden on users to use a different property for throttled response, but the alternative is that this issue for a valuable capability just languishes indefinitely. [1] I'm definitely OK with this compromise with examples and directly linkable docs support.

[1] This ability to distinguish events via two properties would actually be a useful feature in some cases.