morrySnow commented on PR #12490: URL: https://github.com/apache/doris/pull/12490#issuecomment-1241565983
> Just curious, does BE support limit output before calculating projections inside a BE plan node currently? Let's say we have a plan `limit -> project -> olap scan`. After applying the rule, it's rewritten to `project -> limit -> olap scan`. The translated plan would be `OlapScanNode(scan data from underlying olap scanners, limit and then project)` or something else. If so, does BE support this plan(firstly limit and then project inside olap scan) currently? @Kikyou1997 @morrySnow This rule is rewrite `project -> limit` to `limit -> project`. The reason is we could get tree like `project -> limit -> project -> other node`. If we do not rewrite it. we could not merge the two project into one. And if we has more than one project on one node, the second one will overwrite the first one when translate. Then, be will core dump or return `slot cannot find` error. -- 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: commits-unsubscr...@doris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
