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Posted to notifications@iotdb.apache.org by "WangChao (Jira)" <ji...@apache.org> on 2020/04/10 11:38:00 UTC

[jira] [Commented] (IOTDB-557) Use generalized "and" and "or"

    [ https://issues.apache.org/jira/browse/IOTDB-557?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17080427#comment-17080427 ] 

WangChao commented on IOTDB-557:
--------------------------------

"By using generalized "and" and "or", we can replace such a filter tree with just one filter node", how to express it ? I do not understand why it work.

> Use generalized "and" and "or"
> ------------------------------
>
>                 Key: IOTDB-557
>                 URL: https://issues.apache.org/jira/browse/IOTDB-557
>             Project: Apache IoTDB
>          Issue Type: Improvement
>          Components: Planner/SQLOptimizer
>            Reporter: Tian Jiang
>            Priority: Minor
>              Labels: expression, query
>
> We only use binary "and" and "or" in expression construction, as a result, a filter like "root.group1.*.s1 > 1" (* ranges from d1 to d100) will result in a filter tree of over 100 nodes, which could be a great waste when there are even more series. 
> By using generalized "and" and "or", we can replace such a filter tree with just one filter node, which I think could relieve the Java GC a lot.



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