Re: How hard would a "wipe all deletes" operation be?

[Michael McCandless]

You could explore this idea using a custom MergePolicy?​

That would let you run perf. tests on the 35 GB index, comparing
forceMerge, expungeDeletes (TMP), and expungeDeletes (your new MergePolicy).

Mike McCandless

http://blog.mikemccandless.com