Purge old DELETEs during live compaction

[weggert]

This change is to address Issue 112, 'Old deletes need to be purged during Compaction'.

It adds the ability to specify a sirius.log.compaction-max-delete-age-hours configuration property to cause old Delete events to be purged during live compaction.

The configuration property defaults to a very large value, so by default Delete events will not be purged.

It also adds an option to WalTool to purge old Deletes, along with other options for old PUTs.

[weggert]

Pull request https://github.com/Comcast/sirius/pull/113 addresses this issue.

[weggert]

I added documentation to the purge deletes config item, and removed the unnecessary variable from WalTool.

[clinedome-work]

All in all, this looks great. A few minor comments, but with those addressed, I'd be +1. Thanks @weggert!

[weggert]

Per the feedback I pushed up changes to make the SegmentedCompactor private, remove the unnecessary comment, and simplify the Delete purge logic in the SegmentedCompactor.

[clinedome-work]

Awesome. Looks great. :+1: Gonna try and get another set of eyes to :+1: this then it's ready for a squash and merge.

[tbarker9comcast]

Had some minor comments, but once they are addressed this has my :+1:. This looks great to me.

[weggert]

I fixed the typo in the WalTool documentation, and I added a new test for the SegmentedCompactor Delete purge logic to make sure it works as expected when the max-time is bigger than the current time.

There is also a minor change for when getting the property to change siriusConfig.getProp(...) to siriusConfig.getInt(...) to avoid ClassCastExceptions if the property value is set with a Long.

[weggert]

Thanks for the reviews. :-) I squashed the updates into the original commit

[clinedome-work]

:+1: