David DeWitt and Michael Stonebraker , computer scientists specializing in parallel databases and shared-nothing architectures , have been critical of the breadth of problems that MapReduce can be used for.  They called its interface too low-level and questioned whether it really represents the paradigm shift its proponents have claimed it is.  They challenged the MapReduce proponents' claims of novelty, citing Teradata as an example of prior art that has existed for over two decades. They also compared MapReduce programmers to CODASYL programmers, noting both are "writing in a low-level language performing low-level record manipulation."  MapReduce's use of input files and lack of schema support prevents the performance improvements enabled by common database system features such as B-trees and hash partitioning , though projects such as Pig (or PigLatin) , Sawzall , Apache Hive ,  YSmart ,  HBase  and BigTable   are addressing some of these problems.