Sia: Optimizing queries using learned predicates

摘要: Predicate-centric rules for rewriting queries is a key technique in optimizing queries. These include pushing down the predicate below the join and aggregation operators, or optimizing the order of evaluating predicates. However, many of these rules are only applicable when the predicate uses a certain set of columns. For example, to move the predicate below the join operator, the predicate must only use columns from one of the joined tables. By generating a predicate that satisfies these column constraints and preserves the semantics of the original query, the optimizer may leverage additional predicate-centric rules that were not applicable before. Researchers have proposed syntax-driven rewrite rules and machine learning algorithms for inferring such predicates. However, these techniques suffer from two limitations. First, they do not let the optimizer constrain the set of columns that may be used in the learned …