[
https://issues.apache.org/jira/browse/CALCITE-3753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17026946#comment-17026946
]
Julian Hyde commented on CALCITE-3753:
--------------------------------------
[~rkondakov] Calcite's engine always had the capability of "Cascades style
optimization with aggressive search space pruning". That is achieved by the
'importance' concept, the sorted queue of rule matches, and the ability to stop
optimization when the plan stops improving.
But we didn't use the capability because no one ever tuned the 'importance' and
'when to stop' metrics. That empirical tuning is not a matter for the engine.
> Always try to match and execute substitution rule first and remove rulematch
> ordering
> -------------------------------------------------------------------------------------
>
> Key: CALCITE-3753
> URL: https://issues.apache.org/jira/browse/CALCITE-3753
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Haisheng Yuan
> Priority: Major
> Attachments: image-2020-01-27-20-27-57-957.png
>
>
> In VolcanoPlanner, some rules e.g. ProjectMergeRule, PruneEmptyRule can be
> defined as SubstitutionRule, so that we can always try to match and execute
> them first (without deferring rule call). All the other rulematches doesn't
> need to be sorted and rules can be executed in any order they matched, since
> we are going to execute all of them anyway, sooner or later. Computing and
> comparing importances cause a lot of latency.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
