[CalendarServer-users] RequestDelaySeconds in stdconfig

[Andre LaBranche]

Hi,
 
> On Nov 25, 2016, at 11:53 AM, Gaurav Jain <monkeyfdude at gmail.com> wrote:
> 
> Would it help faster recipient inbox update if I change this value to 1 or 2 secs?

RequestDelaySeconds allows time for coalescing of scheduling messages (on their way OUT of the work queue, by setting the 'notBefore' attribute into the future by RequestDelaySeconds on the way IN to the work queue). This is useful because sometimes a flurry of user activity can generate thrashing / feedback. Exactly how busy they get depends on several factors - attendee count is the most obvious, but also number of sharees and delegates.

You can reduce end to end latency by reducing this value, at the cost of additional client / server / network load and database lock heat during busy periods. In general we only turn it down for demos (where wall clock seconds are valued more highly than in actual life). In real-world use, the default delay is generally imperceptible unless you are in the same room as the sender and receiver of a message that is subject to this delay.

https://github.com/apple/ccs-calendarserver/blob/af0b949d1f41475a9e1ac6756f6a79ecde1ff3e7/txdav/caldav/datastore/scheduling/work.py#L361

RequestDelaySeconds is most important for active servers that don't have a lot of headroom relative to their average workloads, and also servers with many users.

In general, the cost (time) difference between a cheap CalDAV request and an expensive one is so vast, we end up needing various (configurable) rate limiters, and this is one of them.

-dre

> 
> Would there be any side effects?
> 
>> On Thu, Nov 24, 2016 at 6:09 PM, Gaurav Jain <monkeyfdude at gmail.com> wrote:
>> Hi,
>> 
>> Can you please tell the meaning of in stdconfig.plist:
>> 
>> <!-- Number of seconds delay for a queued scheduling request/cancel -->
>> <key>RequestDelaySeconds</key>
>> <integer>5</integer>
>> 
>> 
>> Regards,
>> 
>> 
>> 
>> 
> 
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