public class ParallelCompositeReader extends BaseCompositeReader<LeafReader>
CompositeReader
which reads multiple, parallel indexes. Each
index added must have the same number of documents, and exactly the same
number of leaves (with equal maxDoc
), but typically each contains
different fields. Deletions are taken from the first reader. Each document
contains the union of the fields of all documents with the same document
number. When searching, matches for a query term are from the first index
added that has the field.
This is useful, e.g., with collections that have large fields which change rarely and small fields that change more frequently. The smaller fields may be re-indexed in a new index and both indexes may be searched together.
Warning: It is up to you to make sure all indexes
are created and modified the same way. For example, if you add
documents to one index, you need to add the same documents in the
same order to the other indexes. Failure to do so will result in
undefined behavior.
A good strategy to create suitable indexes with IndexWriter
is to use
LogDocMergePolicy
, as this one does not reorder documents
during merging (like TieredMergePolicy
) and triggers merges
by number of documents per segment. If you use different MergePolicy
s
it might happen that the segment structure of your index is no longer predictable.
IndexReader.ReaderClosedListener
Constructor and Description |
---|
ParallelCompositeReader(boolean closeSubReaders,
CompositeReader... readers)
Create a ParallelCompositeReader based on the provided
readers.
|
ParallelCompositeReader(boolean closeSubReaders,
CompositeReader[] readers,
CompositeReader[] storedFieldReaders)
Expert: create a ParallelCompositeReader based on the provided
readers and storedFieldReaders; when a document is
loaded, only storedFieldsReaders will be used.
|
ParallelCompositeReader(CompositeReader... readers)
Create a ParallelCompositeReader based on the provided
readers; auto-closes the given readers on
IndexReader.close() . |
Modifier and Type | Method and Description |
---|---|
protected void |
doClose()
Implements close.
|
docFreq, document, getDocCount, getSequentialSubReaders, getSumDocFreq, getSumTotalTermFreq, getTermVectors, maxDoc, numDocs, readerBase, readerIndex, totalTermFreq
getContext, toString
addReaderClosedListener, close, decRef, document, document, ensureOpen, equals, getCombinedCoreAndDeletesKey, getCoreCacheKey, getRefCount, getTermVector, hasDeletions, hashCode, incRef, leaves, numDeletedDocs, registerParentReader, removeReaderClosedListener, tryIncRef
public ParallelCompositeReader(CompositeReader... readers) throws IOException
IndexReader.close()
.IOException
public ParallelCompositeReader(boolean closeSubReaders, CompositeReader... readers) throws IOException
IOException
public ParallelCompositeReader(boolean closeSubReaders, CompositeReader[] readers, CompositeReader[] storedFieldReaders) throws IOException
IOException
protected void doClose() throws IOException
IndexReader
doClose
in class IndexReader
IOException
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