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From:Zhangzhigang Date:May 7 2012 8:53am
Subject:回复: Why is creating indexes faster afte
r inserting massive data rows?
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johan ....
>Plain and simple: the indices get updated after every insert statement, 
whereas if you only create the index *after* the inserts, the index gets created in a
single operation, which is a lot more efficient..


Ok, Creating the index *after* the inserts, the index gets created in a single operation.
But the indexes has to be updating row by row after the data rows has all been inserted.
Does it work in this way?
So i can not find the different overhead  about two ways.





________________________________
 发件人: Johan De Meersman <vegivamp@stripped>
收件人: Zhangzhigang <zzgang_2008@stripped> 
抄送: mysql@stripped 
发送日期: 2012年5月7日, 星期一, 下午 4:28
主题: Re: Why is creating indexes faster after inserting massive data rows?
 
----- Original Message -----
> From: "Zhangzhigang" <zzgang_2008@stripped>
> 
> Creating indexes after inserting massive data rows is faster than
> before inserting data rows.
> Please tell me why.

Plain and simple: the indices get updated after every insert statement, whereas if you
only create the index *after* the inserts, the index gets created in a single operation,
which is a lot more efficient.

I seem to recall that inside of a transaction (thus, InnoDB or so) the difference is
markedly less; I might be wrong, though.


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Thread
Why is creating indexes faster after inserting massive data rows?Zhangzhigang7 May
  • Re: Why is creating indexes faster after inserting massive data rows?Ananda Kumar7 May
    • 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang7 May
  • Re: Why is creating indexes faster after inserting massive data rows?Johan De Meersman7 May
    • 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang7 May
      • Re: 回复: Why is creating indexes faster after inserting massive data rows?Alex Schaft7 May
        • 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang7 May
          • Re: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Claudio Nanni7 May
            • too nice not to share it!hsv2 Oct
          • Re: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Mihamina Rakotomandimby30 May
      • Re: 回复: Why is creating indexes faster after inserting massive data rows?Claudio Nanni7 May
        • 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang7 May
      • Re: 回复: Why is creating indexes faster after inserting massive data rows?Johan De Meersman7 May
        • RE: 回复: Why is creating indexes faster after inserting massive data rows?Rick James7 May
        • Re: 回复: Why is creating indexes faster after inserting massive data rows?Karen Abgarian7 May
          • 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang8 May
            • Re: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Karen Abgarian8 May
              • 回复: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang8 May
                • Re: 回复: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Johan De Meersman8 May
                  • 回复: 回复: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang8 May
                  • Re: 回复: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Karen Abgarian8 May
                    • 回复: 回复: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang9 May
              • RE: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Rick James10 May
            • Re: 回复: 回复: Why is creating indexes faster after inserting massive data rows?Johan De Meersman8 May
        • Re: 回复: Why is creating indexes faster after inserting massive data rows?Karen Abgarian7 May
    • RE: Why is creating indexes faster after inserting massive datarows?Rick James7 May
      • 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang9 May
        • RE: 回复: Why is creating indexes faster after inserting massive data rows?Rick James9 May
          • Re: 回复: Why is creating indexes faster after inserting massive data rows?Claudio Nanni9 May
          • 回复: 回复: Why is creating indexes faster after inserting massive data rows?Zhangzhigang10 May