deleteAll

Delete all documents in the index.

This method will drop all buffered documents and will remove all segments from the index. This change will not be visible until a .commit has been called. This method can be rolled back using .rollback.

NOTE: this method is much faster than using deleteDocuments( new MatchAllDocsQuery() ). Yet, this method also has different semantics compared to .deleteDocuments since internal data-structures are cleared as well as all segment information is forcefully dropped anti-viral semantics like omitting norms are reset or doc value types are cleared. Essentially a call to .deleteAll is equivalent to creating a new IndexWriter with which a delete query only marks documents as deleted.

NOTE: this method will forcefully abort all merges in progress. If other threads are running .forceMerge, .addIndexes or .forceMergeDeletes methods, they may receive MergePolicy.MergeAbortedExceptions.