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From:Dan Nelson Date:January 12 2009 6:14pm
Subject:Re: Why does changing a table property rebuild the table?
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In the last episode (Jan 12), mos said:
> I'm using MySQL 5.1 and if I execute:
> 
> alter table mytable delay_key_write=1;
> 
> it takes about an hour to rebuild the table. Why? As far as I know it
> is not changing the table structure. So why does it have to make a
> copy of the table and reload all the data?

Mysql plays it safe and assumes that any table modification requires a
full rebuild.  5.1 knows that certain settings don't require a full
rebuild, but delay_key_writes isn't one of them (and some that are
marked as fast shouldn't be - see
http://bugs.mysql.com/bug.php?id=39372 ).

-- 
	Dan Nelson
	dnelson@stripped
Thread
Why does changing a table property rebuild the table?mos12 Jan
  • Re: Why does changing a table property rebuild the table?Dan Nelson12 Jan
    • Re: Why does changing a table property rebuild the table?mos12 Jan
      • Re: Why does changing a table property rebuild the table?Dan Nelson12 Jan
        • Re: Why does changing a table property rebuild the table?Baron Schwartz13 Jan
          • Re: Why does changing a table property rebuild the table?mos14 Jan