Rewriting procedures for batched bindings

Queries, or calls to stored procedures/user-defined functions are often invoked multiple times, either from within a loop in an application program, or from the where/select clause of an outer query. When the invoked query/procedure/function involves database access, a naive implementation can result in very poor performance, due to random I/O. Query decorrelation addresses this problem in the special case of nested sub-queries, but is not applicable otherwise. This problem is traditionally addressed by manually rewriting the application to make it set-oriented, by creating a batch of parameters, and by rewriting the query/procedure to work on the batch instead of one parameter at a time. Such manual rewriting is time-consuming and error prone. In this paper, we propose techniques that can be used to do the following. (a) Automatically rewrite programs to replace multiple calls to a query by a batched call to a correspondingly rewritten query. (b) Rewrite a stored procedure/function t...

• Type: Journal
• Year: 2008
• Where: PVLDB
• Authors: Ravindra Guravannavar, S. Sudarshan
• Keywords: Outer Query, PVLDB 2008, Rewritten Query, Significant Performance Problems