alamb commented on issue #14993:
URL: https://github.com/apache/datafusion/issues/14993#issuecomment-2704068023

   > Or are you suggesting this is the mechanism by which all expression 
push-down occurs, by faking additional schema columns?
   
   I think I was suggesting this (though I haven't thought about the API it too 
carefully)
   
   Basically the TableSource would somehow have to say "I can evaluate this 
expression" and then have to tell DataFusion somehow what column corresponded 
to that expression. 
   
   Maybe a good first step would be to try and code up an example showing how 
to "push down" a field access
   
   like input is a column `user` with documents like 
   ```json
   { id : 124
     name: 'foo'
   },
   { id : 567
     name: 'bar'
   }
   ```
   
   And the table provider also has a `shredded` column like
   
   ```
   foo
   bar
   ```
   
   And the idea is to show how a query like
   
   ```sql
   select user['name'] from table
   ```
   
   Could be evaluated using the table provider using the separate shredded 
column
   
   


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For additional commands, e-mail: github-h...@datafusion.apache.org

Reply via email to