Column-oriented databases have become fashionable following the work of Stonebraker et al. In the data warehousing industry, the terms "column oriented" and "column store" have become necessary marketing buzzwords. One of the benefits of column-oriented indexes is good compression through run-length encoding (RLE). This type of compression is particularly benefitial since it simultaneously reduce the volume of data and the necessary computations. However, the efficiency of the compression depends on the order of the rows in the table and this is even more important with larger tables. Finding the best row ordering is NP hard. We compare some heuristics for this problem including variations on the lexicographical order, Gray codes, and Hilbert space-filling curves.