Index Key Compression and On-the-Fly Reconstruction of In-Memory Indexes

This article proposes an index key compression scheme based on the notion of distinction bits. It proves that the distinction bits of index keys are sufficient information to determine the sorted order of the index keys. The actual compression ratio may vary depending on the characteristics of datasets (an average of 2.76:1 compression ratio was observed in the authors’ experiments). However, the index key compression scheme leads to significant performance improvements during the reconstruction of large-scale indexes. This study’s index key compression can be effectively used for database replication and index recovery in modern main-memory database systems.