Helper class to sort readers that contain blocks of documents.
Provides index sorting capablities. The application can use any Sort specification, e.g. to sort by fields using DocValues or FieldCache, or to reverse the order of the documents (by using SortField.Type.DOC in reverse). Multi-level sorts can be specified the same way you would when searching, by building Sort from multiple SortFields.
SortingMergePolicy can be used to
make Lucene sort segments before merging them. This will ensure that every
segment resulting from a merge will be sorted according to the provided
Sort. This however makes merging and
thus indexing slower.
Sorted segments allow for early query termination when the sort order matches index order. This makes query execution faster since not all documents need to be visited. Please note that this is an expert feature and should not be used without a deep understanding of Lucene merging and document collection.
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