[
https://issues.apache.org/jira/browse/DRILL-4541?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jinfeng Ni reassigned DRILL-4541:
---------------------------------
Assignee: Jinfeng Ni
> Make sure query planner does not generate operators with mixed convention
> trait
> -------------------------------------------------------------------------------
>
> Key: DRILL-4541
> URL: https://issues.apache.org/jira/browse/DRILL-4541
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Reporter: Jinfeng Ni
> Assignee: Jinfeng Ni
>
> Per the discussion [1] in the PR of DRILL-4531, we should fix the query
> planner rules used in Drill planning, such that it will not generate Rels
> with mixed convention trait. For instance, a LogicalFilter should only have
> child with NONE convention; it should not have child with LOGICAL convention.
>
> The mixed Rels will cause planner either hang (as reported in DRILL-4531 and
> DRILL-3257), or do wasted work by firing rules against the mixed Rels.
> I think the reason that we have such mixed rels is we have different kinds of
> rules, used in a single Volcano planning phase.
> 1) Rule matchs base class Filter/Project, etc only.
> 2) Rule matches LogicalFilter/LogicalProject, etc
> 3) Rule matches DrillFilter/DrillProject, etc.
> 3) Rule uses copy() method to generate a new Rel
> 4) Rule uses RelFactory to generate a new Rel.
> 5) convent rule, which convert from Calcite logical (NONE/Enumerable) to
> Drill logical (LOGICAL)
> For instance, ProjectMergeRule, which matches base Project, yet uses default
> RelFactory, will match both LogicalProject and DrillProject, but produce
> LogicalProject as outcome. That will cause the mixed rels.
> 2 things we may consider to fix this:
> 1) Separate the convent rules from the other transformation rules. Apply
> convert rule first, then all the transformation rules match DrillLogical
> only.
> 2) Every rule that Drill uses, except for convert rules, should assert the
> convention of input and output have the same convention.
> [1] https://github.com/apache/drill/pull/444
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
