Pipelining in Query Processing
In the earlier section, we learned about materialization in which we evaluate multiple operations in the given expression via temporary relations. But, it leads to a drawback of producing a high number of temporary files. It makes the query-evaluation less efficient. However, the evaluation of the query should be highly efficient in producing an effective output.
Here, we will discuss another method of evaluating the multiple operations of an expression that works more efficiently than materialization. Such a more efficient way is known as Pipelining. Pipelining helps in improving the efficiency of the query-evaluation by decreasing the production of a number of temporary files. Actually, we reduce the construction of the temporary files by merging the multiple operations into a pipeline. The result of one currently executed operation passes to the next operation for its execution, and the chain continues till all operations are completed, and we get the final output of the expression. Such type of evaluation process is known as Pipelined Evaluation.
Advantages of Pipeline
There are following advantages of creating a pipelining of operations:
Pipelining vs. Materialization
Although both methods are used for evaluating multiple operations of expression, there are few differences between them. The difference points are described in the below table: