Rolling back the optimizations from commit: af8532c471fd8182dae8f2657686b139ce0f4a6e.  Lookups were failing for indices beyond the cache.  Garbage was being grabbed from beyond the cache which would cause spurious failures in testdir_multi_jvm/test_many_fp_formats_libsvm_2_fvec.py, especially in cases with a single value in a column.