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The following page has been changed by Arun C Murthy: http://wiki.apache.org/lucene-hadoop/SequenceFile ------------------------------------------------------------------------------ There are 3 different !SequenceFile formats: 1. Uncompressed key/value records. 2. Record compressed key/value records - only 'values' are compressed here. - 3. Block compressed key/value records - both keys are values are collected in 'blocks' separately and compressed. + 3. Block compressed key/value records - both keys are values are collected in 'blocks' separately and compressed.The size of the 'block' is configurable. The recommended way is to use the SequenceFile.createWriter methods to construct the 'preferred' writer implementation. @@ -47, +47 @@ ===== BlockCompressed Writer Format ===== * [#SeqFileHeader Header] * Record ''Block'' + * A sync-marker to help in seeking to a random point in the file and then seeking to next ''record block''. * !CompressedKeyLengthsBlockSize * !CompressedKeyLengthsBlock * !CompressedKeysBlockSize @@ -55, +56 @@ * !CompressedValueLengthsBlock * !CompressedValuesBlockSize * !CompressedValuesBlock - * A sync-marker to help in seeking to a random point in the file and then seeking to next ''record block''.
