[
https://issues.apache.org/jira/browse/CALCITE-4996?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17487299#comment-17487299
]
Stamatis Zampetakis commented on CALCITE-4996:
----------------------------------------------
At some point we had to deal with a similar problem but couldn't recall the
details. After some thought it came back to me but our solution was far from
ideal as we basically wrote our own {{RelJsonReader}}. By doing this we could
use a custom {{RelInput}} inside {{readRel}} method. Like that we didn't have
to have rely on some specific {{RelOptSchema}} to reconstruct {{RelNodes}} but
we were creating the types from the content of the JSON string.
Long story short we could get back a complete {{RelNode}} tree which looked
like the original but kinda fake cause there wasn't any real validation against
a schema.
I now understand better what's the goal of this PR thanks for the feedback
[~mkou] and [~julianhyde]. Since Julian is following this closely I completely
trust his judgement but if I can help with anything let me know.
> [RelJson] create a new public toRex method which can override makeInputRef
> --------------------------------------------------------------------------
>
> Key: CALCITE-4996
> URL: https://issues.apache.org/jira/browse/CALCITE-4996
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Marieke Gueye
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 40m
> Remaining Estimate: 0h
>
> In the case of our project, the environment that generates a JSON from a
> RexNode and the environment that reads it are different. We need to
> "translate" the inputs into their aliases in the new cluster.
> This method will permit to give more freedom to the JSON RexNode parser if
> needed.
> {code}
> /**
> * Transforms a RexNode tree defined in a map (from a JSON) into a RexNode
> * Applying a special method to inputs instead of transforming them into
> inputRef
> * @param cluster The optimization environment
> * @param apply is a InputTranslator lambda that transforms the map
> representing input
> * references into a RexNode
> * @param o the map derived from a RexNode transformed into a JSON
> * @return the transformed RexNode
> */
> {code}
> Make sure that {{RexNode toRex(RelInput relInput, @PolyNull Object o)}} is
> still working + adding tests
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
