[jira] [Comment Edited] (KYLIN-3072) Fix the regular expression in function 'removeCommentInSql'

["peng.jianhua (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KYLIN-3072?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16274001#comment-16274001 ] 

peng.jianhua edited comment on KYLIN-3072 at 12/1/17 6:21 AM:
--------------------------------------------------------------

Hi [~Shaofengshi], I'm sorry. I did not describe this issue clearly. If you still think there is no problem, I will close the issue according to your review. The essence of this problem is that the logic of parsing is flawed. The current logic is as following:
1. Firstly,  the "--" was parsed.
2. Secondly, the "/* */" was parsed.
Based on the above parsing logic, once the "/\* */" contains the "--" and the "\*/" and the "--" are in the same line , the parsing will be wrong. Because the "\*/" will be removed when the program parses the "--". When parsing the "/\* */" again, the program parses fail because the "\*/" was removed.

What we modify is the wrong logic of the program. Based on the above logic modification, all possible combinations will not be a problem, do you think?


was (Author: peng.jianhua):
Hi [~Shaofengshi], I'm sorry. I did not describe this issue clearly. If you still think there is no problem, I will close the issue according to your review. The essence of this problem is that the logic of parsing is flawed. The current logic is as following:
1. Firstly,  the "--" was parsed.
2. Secondly, the "/* */" was parsed.
Based on the above parsing logic, once the "/* */" contains the "--" and the "*/" and the "--" are in the same line , the parsing will be wrong. Because the "*/" will be removed when the program parses the "--". When parsing the "/* */" again, the program parses fail because the "*/" was removed.

What we modify is the wrong logic of the program. Based on the above logic modification, all possible combinations will not be a problem, do you think?

> Fix the regular expression in function 'removeCommentInSql'
> -----------------------------------------------------------
>
>                 Key: KYLIN-3072
>                 URL: https://issues.apache.org/jira/browse/KYLIN-3072
>             Project: Kylin
>          Issue Type: Bug
>          Components: Query Engine
>            Reporter: peng.jianhua
>            Assignee: peng.jianhua
>         Attachments: 0001-KYLIN-3072-Fix-the-regular-expression-in-function-re.patch, 01.png, 02.PNG
>
>
> select * from kylin_sales /\*comments--comments*/
> we should remove comments like '/\*comments*/' first,then remove comments like '--comments' , or the sql above will have an exception.
> please refer to 01.png.
> if we exchange the sequence of this two comment patterns,we will get 02.png.



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