Method ExpungeDeletes

Just like ExpungeDeletes(), except you can specify whether the call should block until the operation completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.

Expunges all deletes from the index. When an index has many document deletions (or updates to existing documents), it's best to either call optimize or expungeDeletes to remove all unused data in the index associated with the deleted documents. To see how many deletions you have pending in your index, call NumDeletedDocs This saves disk space and memory usage while searching. expungeDeletes should be somewhat faster than optimize since it does not insist on reducing the index to a single segment (though, this depends on the MergePolicy; see FindMergesToExpungeDeletes(SegmentInfos).). Note that this call does not first commit any buffered documents, so you must do so yourself if necessary. See also ExpungeDeletes(Boolean)

NOTE: if this method hits an OutOfMemoryError you should immediately close the writer. See above for details.