Class ParallelCompositeReader
- All Implemented Interfaces:
Closeable
,AutoCloseable
CompositeReader
which reads multiple, parallel indexes. Each index added
must have the same number of documents, and exactly the same hierarchical subreader structure,
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.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader
IndexReader.ReaderClosedListener
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Constructor Summary
ConstructorsConstructorDescriptionParallelCompositeReader
(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 onIndexReader.close()
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Method Summary
Methods inherited from class org.apache.lucene.index.BaseCompositeReader
docFreq, document, getDocCount, getSequentialSubReaders, getSumDocFreq, getSumTotalTermFreq, getTermVectors, maxDoc, numDocs, readerBase, readerIndex, totalTermFreq
Methods inherited from class org.apache.lucene.index.CompositeReader
getContext, toString
Methods inherited from class org.apache.lucene.index.IndexReader
addReaderClosedListener, close, decRef, document, document, ensureOpen, equals, getCombinedCoreAndDeletesKey, getCoreCacheKey, getRefCount, getTermVector, hasDeletions, hashCode, incRef, leaves, numDeletedDocs, open, open, open, open, open, registerParentReader, removeReaderClosedListener, tryIncRef
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Constructor Details
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ParallelCompositeReader
Create a ParallelCompositeReader based on the provided readers; auto-closes the given readers onIndexReader.close()
.- Throws:
IOException
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ParallelCompositeReader
public ParallelCompositeReader(boolean closeSubReaders, CompositeReader... readers) throws IOException Create a ParallelCompositeReader based on the provided readers.- Throws:
IOException
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ParallelCompositeReader
public ParallelCompositeReader(boolean closeSubReaders, CompositeReader[] readers, CompositeReader[] storedFieldReaders) throws IOException Expert: create a ParallelCompositeReader based on the provided readers and storedFieldReaders; when a document is loaded, only storedFieldsReaders will be used.- Throws:
IOException
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Method Details
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doClose
Description copied from class:IndexReader
Implements close.- Specified by:
doClose
in classIndexReader
- Throws:
IOException
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