[jira] [Commented] (IOTDB-1572) Should not change object's state in toString()

["Haonan Hou (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IOTDB-1572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17404319#comment-17404319 ] 

Haonan Hou commented on IOTDB-1572:
-----------------------------------

It makes sense!

Would you like to submit a PR to fix it?

> Should not change object's state in toString()
> ----------------------------------------------
>
>                 Key: IOTDB-1572
>                 URL: https://issues.apache.org/jira/browse/IOTDB-1572
>             Project: Apache IoTDB
>          Issue Type: Bug
>          Components: Core/Engine
>            Reporter: GaoYang
>            Priority: Minor
>
> I meet a strange problem.
>  When I debug memtable flushing, I do as follows:
>  1. insert into root.a.c(time,s1) values (207,2)
>  2. insert into root.a.c(time,s1) values (203,2)
>  According to the code logic, after the second insertion complete, the "sorted" in TVList should be false.
>  But, every time when I look into the value of "sorted" in TVList from memChunk, where the debug breakpoint in, it's always true!
>  I am sure there is no flush or query be triggered between the insertion and breakpoint.
>  After several hours' efforts, I found the cause:
>  1. When debuging, IDEA will invoke Object's toString() method by default.
>  2. This kind of invoke cannot be suspended by breakpoint
>  3. In WritableMemChunk's toString() method, getSortedTVListForQuery() has been invoked, which will trigger a sorting in TVList, has been invoked. And after sorting, "sorted" will be set to true...
> Certainly, it's not a bug and can be bypassed by disable IDEA's auto invoking.
>  In my opinion, it's better not to change object's state in toString method, after all, toString is a representation of object's current state, it should be a method sth like read-only.
> At last, WritableMemChunk's toString() method only want to print the min and max point, which can be found with a simple traversal.
>  



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