[
https://issues.apache.org/jira/browse/CALCITE-2855?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16772673#comment-16772673
]
godfrey he edited comment on CALCITE-2855 at 2/20/19 6:45 AM:
--------------------------------------------------------------
Yes. There is a cache to store previous metadata results for each RelNode in
each RelMetadataQuery instance. We do meet serious performance problems on
complex query (e.g. TPC-DS).
There is a case: ColumnInterval is a new handler that returns the interval of
given column for a RelNode, and a new Selectivity handler is implemented based
on ColumnInterval. AFAIK, Selectivity handler is used by high frequency when
computing cost in Calcite. A new extended RelMetadataQuery instance will be
created each time when ColumnInterval is called in Selectivity, so the cache in
extended RelMetadataQuery instance is unhelpful.
was (Author: godfreyhe):
Yes. There is a cache to store previous metadata results for each RelNode in
each RelMetadataQuery instance. We do meet serious performance problems on
complex query (e.g. TPC-DS).
There is a case: ColumnInterval is a new handler that returns the interval of
given column for a RelNode, and a new Selectivity handler is implemented based
on ColumnInterval. Selectivity handler is used by high frequency when
computing cost in Calcite. A new extended RelMetadataQuery instance will be
created each time when ColumnInterval is called in Selectivity, so the cache in
extended RelMetadataQuery instance is unhelpful.
> Make RelOptCluster constructor public
> -------------------------------------
>
> Key: CALCITE-2855
> URL: https://issues.apache.org/jira/browse/CALCITE-2855
> Project: Calcite
> Issue Type: Improvement
> Reporter: godfrey he
> Assignee: Julian Hyde
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.19.0
>
> Time Spent: 1h
> Remaining Estimate: 0h
>
> Expose RelOptCluster Constructor outside package to allow override.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
