Hadoop Hive - ORC Files
ORC File Format File Structure Stripe Structure HiveQLSyntax Serialization and Compression Integer Column Serialization String Column Serialization Compression ORC File Format The Optimized Row Columnar (ORC) file format provides a highly efficient way to store Hive data. It was designed to overcome limitations of the other Hive file formats. Using ORC files improves performance when Hive is readi
ORCFile in HDP 2: Better Compression, Better Performance - Cloudera Blog
ORCFile in HDP 2: Better Compression, Better Performance The upcoming Hive 0.12 is set to bring some great new advancements in the storage layer in the forms of higher compression and better query performance. Higher Compression ORCFile was introduced in Hive 0.11 and offered excellent compression, delivered through a number of techniques including run-length encoding, dictionary encoding for stri
Byte-dictionary encoding - Amazon Redshift
In byte dictionary encoding, a separate dictionary of unique values is created for each block of column values on disk. (An Amazon Redshift disk block occupies 1 MB.) The dictionary contains up to 256 one-byte values that are stored as indexes to the original data values. If more than 256 values are stored in a single block, the extra values are written into the block in raw, uncompressed form. Th
Text255 and Text32k encodings - Amazon Redshift
Text255 and text32k encodings are useful for compressing VARCHAR columns in which the same words recur often. A separate dictionary of unique words is created for each block of column values on disk. (An Amazon Redshift disk block occupies 1 MB.) The dictionary contains the first 245 unique words in the column. Those words are replaced on disk by a one-byte index value representing one of the 245
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