Hi Hao Jiang Regarding your first question why RLE is controlled by aggKeyBlock. There is dictionary and no-dictionary column type in carbon. carbon sort the column data and then store it. Due to sorting index will get shuffled. Hence for no dictionary data RLE is applied on index and not on data because it is no dictionary data. thus in BlockIndexerStorageForInt@compressMyOwnWay, RLE happens on index. compressDataMyOwnWay is done only for dictionary data.
Regarding your second question Measure data are not sorted and hence sequential delta may be either big or small for e.g if data is 2,-3,4,-6 then sequential delta will be(-5,7,-10,-6) Other then max min delta, we do type conversion also to reduce storage space -- View this message in context: http://apache-carbondata-mailing-list-archive.1130556.n5.nabble.com/Question-about-RLE-and-DELTA-encoding-tp4441p4451.html Sent from the Apache CarbonData Mailing List archive mailing list archive at Nabble.com.
