You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@calcite.apache.org by "Danny Chen (Jira)" <ji...@apache.org> on 2019/10/11 11:00:00 UTC
[jira] [Resolved] (CALCITE-3379) Support expand STRING column
expression of table during sql-to-rel conversion
[ https://issues.apache.org/jira/browse/CALCITE-3379?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Danny Chen resolved CALCITE-3379.
---------------------------------
Resolution: Fixed
Finally i changed my idea and provide a default impl to support string column expression, Fixed in [22c76fb|https://github.com/apache/calcite/commit/22c76fb8e0a3ec363332caf7eb8e46071ace798e] !
> Support expand STRING column expression of table during sql-to-rel conversion
> -----------------------------------------------------------------------------
>
> Key: CALCITE-3379
> URL: https://issues.apache.org/jira/browse/CALCITE-3379
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.21.0
> Reporter: Danny Chen
> Assignee: Danny Chen
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.22.0
>
> Time Spent: 2h 40m
> Remaining Estimate: 0h
>
> Now there are 2 ways to convert a RelOptTable to LogicalTableScan:
> 1. One way is to open the Config#isConvertTableAccess[1] flag and the SqlToRelConverter would invoke the #toRel method which transforms the table to a node returned by the user(Usually a table scan).
> 2. Another way is to use the LogicalTableScan rule, this rule would invoke RelOptTable#toRel and wrap the returned node with a LogicalTableScan.
>
> The difference between 1 and 2 is that, 2 happens in the planning rule but 1 happens in sql-to-rel conversion, 1 also supports to expand the table columns based on the defined default values expressions, see InitializerExpressionFactory#newColumnDefaultValue.
>
> The problem with the InitializerExpressionFactory#newColumnDefaultValue is that it uses InitializerContext#convertExpression to convert a SqlNode, but if the SqlNode is not validated, we always got a RexCall with SqlUnresolvedFunction. We should give the user chance to validate their SqlNode or even we can support pure string expressions which can be used to persist.
>
> Another problem with #toRel is that after the expressions applied as a projection, user has no chance to apply any other relational nodes if they want, we can actually support this, the same way as we support the column expressions.
>
> [1]https://github.com/apache/calcite/blob/2dc97e6723e1b5bf762540f87ffffb5cd1a848a1/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java#L5605
--
This message was sent by Atlassian Jira
(v8.3.4#803005)