Code Generation Techniques for Raw Data Processing
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The motivation of the current study was to design an algorithm that can speed up the processing of a query. The important feature is generating code dynamically for a specific query. We present the technique of code generation that is applied to query processing on a raw file. The idea was to customize a query program with a given query and generate a machine- and query-specific source code. The generated code is compiled by GCC, Clang or any other C/C++ compiler, and the compiled file is dynamically linked to the main program for further processing. Code generation reduces the cost of generalizing query processing. It also avoids the overhead of the conventional interpretation during achieve high performance. Database Management Systems (DBMSs) perform excellent jobs in many aspects of big data, such as storage, indexing, and analysis. DBMSs typically format entire data and load them into their storage layer. They increase data-to-query time, which is the cost time it takes to convert data into a specific schema and persist them in a disk. Ideally, DBMSs should adapt to the input data and extract one/some of columns, not the entire data, that is/are associated with a given query. Therefore, the query engine on a raw file can reduce the cost of conventional general operators and avoid some unnecessary procedures, such as fully scanning, tokenizing and paring the whole data. In the current study, we introduce our code-generation approach for in-situ processing of raw files, which is based on the template approach and the hype approach. The approach minimizes the data-to-query time and achieves a high performance for query processing. There are some benefits from our work: reducing branches and instructions, unrolling loops, eliminating unnecessary data type checks and optimizing the binary code with a compiler on a local machine.
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