[jira] [Created] (CALCITE-828) Change all built-in rules to use a RelBuilder rather than type-specific RelNode factories

["Julian Hyde (JIRA)" <ji...@apache.org>]

Julian Hyde created CALCITE-828:
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             Summary: Change all built-in rules to use a RelBuilder rather than type-specific RelNode factories
                 Key: CALCITE-828
                 URL: https://issues.apache.org/jira/browse/CALCITE-828
             Project: Calcite
          Issue Type: Bug
            Reporter: Julian Hyde
            Assignee: Julian Hyde


Many planner rules create filters, projects, joins, ... and over the years people have made them generic, so they can create different particular sub-classes of RelNodes (say DrillFilter or HiveProject) by adding factories (interfaces defined in RelFactories).

But then people extend a rule, so that a rule that used to only create projects now might sometimes create a filter. They now need to add an extra parameter to the instance of the rule, which is painful. Also, rules may call into utility methods such as RelOptUtil.pushDownJoinConditions (see CALCITE-826), which have similar problems.

The solution is to get rid of factories in public interfaces and instead pass around a RelBuilder. A particular instance of RelBuilder has a factory inside it for each type of RelNode. In general a particular client of Calcite (e.g. Hive) will be able to use the same RelBuilder throughout a query.

Rules are static, so a rule instance cannot contain a RelBuilder, only a ProtoRelBuilder, which can create a RelBuilder given a RelOptCluster and RelOptSchema.



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