Julian Hyde created CALCITE-3923: ------------------------------------ Summary: Refactor how planner rules are parameterized Key: CALCITE-3923 URL: https://issues.apache.org/jira/browse/CALCITE-3923 Project: Calcite Issue Type: Bug Reporter: Julian Hyde
People often want different variants of planner rules. An example is {{FilterJoinRule}}, which has a 'boolean smart’ parameter, a predicate (which returns whether to pull up filter conditions), operands (which determine the precise sub-classes of {{RelNode}} that the rule should match) and a {{RelBuilderFactory}} (which controls the type of {{RelNode}} created by this rule). Suppose you have an instance of {{FilterJoinRule}} and you want to change {{smart}} from true to false. The {{smart}} parameter is immutable (good!) but you can’t easily create a clone of the rule because you don’t know the values of the other parameters. Your instance might even be (unbeknownst to you) a sub-class with extra parameters and a private constructor. So, my proposal is to put all of the config information of a {{RelOptRule}} into a single {{config}} parameter that contains all relevant properties. Each sub-class of {{RelOptRule}} would have one constructor with just a ‘config’ parameter. Each config knows which sub-class of {{RelOptRule}} to create. Therefore it is easy to copy a config, change one or more properties, and create a new rule instance. Adding a property to a rule’s config does not require us to add or deprecate any constructors. The operands are part of the config, so if you have a rule that matches a {{EnumerableFilter}} on an {{EnumerableJoin}} and you want to make it match an {{EnumerableFilter}} on an {{EnumerableNestedLoopJoin}}, you can easily create one with one changed operand. The config is immutable and self-describing, so we can use it to automatically generate a unique description for each rule instance. (See the email thread [[DISCUSS] Refactor how planner rules are parameterized|https://lists.apache.org/thread.html/rfdf6f9b7821988bdd92b0377e3d293443a6376f4773c4c658c891cf9%40%3Cdev.calcite.apache.org%3E].) -- This message was sent by Atlassian Jira (v8.3.4#803005)