![]() ![]() ![]() LiveDocsFormat handles the optional bitset marking which documents are not deleted.TermVectorsFormat encodes per-document term vectors.The default uses block compression, and there have been many improvements recently, especially around compression, merge and CheckIndex performance. StoredFieldsFormat encodes each document's stored fields. #APACHE LUCENE INDEX CODE#This was a big step forward for Lucene because it presents a much lower barrier to research and innovation in the index file formats than before when the bit-level encoding details were scattered throughout the code base.Įach format exposed by the codec in turn provides reading APIs, used at search-time, and writing APIs, used during indexing. The codec is set per segment and every segment is free to use a different codec, though that's uncommon. This is a vital core abstraction: it isolates all the other complex logic of searching and indexing from the low-level details of how data structures are stored on disk and in RAM. Whenever Lucene needs to access the index, it does so entirely through the codec APIs. Each codec has a unique string name, such as “Lucene410", and implements methods to return a separate Format class for each part of Lucene's index. The codec's name is registered with Java's Service Provider Interface (SPI) so you can easily get the Codec instance at any time from just its name. The codec is a concrete instance of the abstract You've likely heard that Apache Lucene uses something called a codec to read and write index files. ![]()
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