A Trace-Based JIT Compilation Framework for XQuery

Query is a functional language for querying XML data. In network environment, queries are generated dynamically and executed in interpretation way. This means query programs cannot be compiled in advance to achieve a high efficiency. The just-in-time (JIT) compliation technique base on method or trace have been propsed to utilize the compilation technique. Since queries are usually short and lack of user-defined functions, we think the trace-based JIT compilation is more applicable than the method-based compilation. In this paper, we propose a trace-based JIT compilation framework to improve the performance of Query execution. Program branches executed frequently are identified as traces and compiled into object codes. We also improve the trace detection technique. Interconnected traces are merged into a trace tree and compiled at runtime to avoid unnecessary overhead of execution environment alternation between interpretation and compilation. Experiment results show our trace-based JIT compilation is more efficient than interpretation and method-based JIT compilation.