Sorting is a crucial operation that could be used to implement SQL operators such as GROUP BY, ORDER BY, and SQL:2003 PAR-TITION BY. Queries with multiple attributes in those clauses are common in real workloads. When executing queries of that kind, state-of-the-art main-memory column-stores require one round of sorting per input column. With the advent of recent fast scans and denormalization techniques, that kind of multi-column sorting could become a bottleneck. In this paper, we propose a

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... w technique called "code massaging", which manipulates the bits across the columns so that the overall sorting time can be reduced by eliminating some rounds of sorting and/or by improving the degree of SIMD data level parallelism. Empirical results show that a mainmemory column-store with code massaging can achieve speedup of up to 4.7X, 4.7X, 4X, and 3.2X on TPC-H, TPC-H skew, TPC-DS, and real workload, respectively.