[CALCITE-3769] Deprecate TableScanRule

• Type: Wish
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.21.0
• Fix Version/s: 1.22.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Danny Chen
• Reporter: Danny Chen
• Created: 05/Feb/20 01:36
• Updated: 06/Mar/20 04:36
• Resolved: 14/Feb/20 02:25

Description

The TableScanRule is the only planner rule that for a logical node(e.g. the table scan), its function is to pass along the cluster object and invoke the RelOptTable#toRel which is very trivial because it supplies only a simple ToRelContext that does not support expanding view/passing table hints.

For rels that come from the sql-to-rel conversion, there is already a table conversion logic[1]. This code gives a more powerful ToRelContext that has the complete functionality.

The only reason that I saw the meaning of existing TableScanRule is for the TableScan that comes from the RelBuilder#scan.

So I would suggest to deprecate the TableScanRule, instead, we support translating the table directly in RelBuilder#scan,

We also add a new interface RelBuilder#scan(Iterable<String> tableNames, ToRelContext context), so that user can pass in a more powerful ToRelContext explicitly. User can customize a TableScanFactory in the RelBuilder to do this.

[1] https://github.com/apache/calcite/blob/d6fa25cd11625ad7b4b74dafbd0211c701b38d49/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java#L3498

Issue Links

• relates to: CALCITE-3798 Make RelBuilder view expander pluggable
• relates to: CALCITE-3801 Deprecate SqlToRelConverter.Config#isConvertTableAccess
• links to: GitHub Pull Request #1787
• links to: GitHub Pull Request #1790
• links to: GitHub Pull Request #1841