In this talk, we present the PaStiX sparse supernodal solver, using hierarchical compression to reduce the burden on large blocks appearing during the nested dissection process. To improve the efficiency of our sparse update kernel for both BLR (block low rank) and HODLR (hierarchically off-diagonal low-rank), we investigate to BDLR (boundary distance low-rank) method to preselect rows and columns in the low-rank approximation algorithm. We will also discuss ordering strategies to enhance data locality and compressibility.