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From:samk Date:March 22 2009 2:33am
Subject:Re: copy blob between tables may get in consistent data?
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See Thread at: http://www.techienuggets.com/Detail?tx=78262 Posted on behalf of a User

I have no problems in copying MEDIUMBLOB type data from one table to another. Under either
5.0 or 5.1 community editions.

In Response To: 

hi,
  I found this:  http://bugs.mysql.com/bug.php?id=34300   in the bug system.
  As it descibed, there is chance which I get corrupted data when read BLOB.
Now I wonder why I also get corrupted data when write BLOB into table...
  I tried this:
    step 1: read BLOB data from TABLE1
    step 2: log the BLOB data
    step 3: write the data into TABLE2

  result:
    select hex(data) from TABLE1   is the same as      what I've logged in step2
    select hex(data) from TABLE2   is different with   select
hex(data) from TABLE2

  Any suggestions?

2009/3/19 Cui Shijun <noway@stripped>:
> hi,
>  I'm using mysql-5.1.22, innodb. For some reason, I need to add some
> columns to a table without locking it, so I do this:
>
>     insert into TABLE2(col1, col2, ... ,colN) select col1,
> col2, ...
> colN from TABLE1 where ...(primary key traversal condition).
>
>  which TABLE1 is under use, and TABLE2 has new structure.
>  Before I really do the copy task, I created some triggers to
> synchronize the insert & update.
>
>  When I finally complete the task, I find ALL blob column appear to
> result in inconsistent status with the orignal table.
>  There are users which do query and update on TABLE1.
>  So what's going wrong?
>
>  Thank you
>       Cui Shijun
>

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Thread
copy blob between tables may get in consistent data?Cui Shijun19 Mar
  • Re: copy blob between tables may get in consistent data?Cui Shijun20 Mar
Re: copy blob between tables may get in consistent data?samk22 Mar