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The "FileFormatDesignDoc" page has been changed by StuHood. http://wiki.apache.org/cassandra/FileFormatDesignDoc?action=diff&rev1=23&rev2=24 -------------------------------------------------- === Field reordering === - One weakness of the implementation so far is that it doesn't allow tuples to be reordered within a level. This approach performs well for wide rows with high field cardinality, since adding compression is unlikely to remove data. + One weakness of the implementation so far is that it preserves the order of tuples within a level. This approach performs well for wide rows with high field cardinality, since adding compression is unlikely to remove data. - Since we have domain knowledge that a compression algorithm would not, it will often be more efficient to perform reordering by ourselves, particularly when a chunk has low cardinality: for example at the "name2" level above. By assigning the chunk an ordering of ''self'' (as opposed to ''parent''), we can store the fields in sorted order (rather than in ''parent''-sorted order) and remove duplicates. + But since we have domain knowledge that a compression algorithm would not, it will often be more efficient to perform reordering by ourselves, particularly when a chunk has low cardinality: for example at the "name2" level above. By assigning the chunk an ordering of ''self'' (as opposed to ''parent''), we can store the fields in sorted order (rather than in ''parent''-sorted order) and remove duplicates. || ''name2'' || || flavor ||
