Reduced unwanted Object creation

[RobAustin]

This relates to the following support issue -- https://support.chronicle.software/staff/ticket/422

The following is from a YourKit Dump

[nicktindall]

Just shooting from the hip here, could this be related to the removal of the caching in that area, now we are ending up looking to the file system more often to see which cycles are there? I wonder if we could use a WatchService to eliminate unnecessary directory listings (i.e. only refresh when there are changes)? or if that would also be garbage-y?

https://docs.oracle.com/javase/tutorial/essential/io/notification.html

[glukos]

@nicktindall
I don't think we can get rid of scanning through queue directory, but WatchService is a good idea, thanks. We can trigger refresh only on WatchService event (ideally, only on removes) instead of doing it every minute.
Allocation burst on refresh is reproducible - all we need is creating enough queue files:

I'll start with optimizing it

[JerryShea]

May be worth doing #913 while you are looking at this

[glukos]

@nicktindall @JerryShea @RobAustin
Please see #925.
I think the allocations issue is mostly resolved by the patch, but refresh operation is still CPU consuming (and may cause latency spikes). I've created a separate #924 for using WatchService.

[hft-team-city]

Released in Chronicle-Queue-5.21.92, BOM-2.21.237