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From:Gaspar Bakos Date:June 10 2006 6:25pm
Subject:dropping primary key - 99%CPU
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Hi,

Could someone explain why dropping a primary key of a table (of
~1million rec) may take up to minutes of time and 99%CPU?

Naively, I would have thought that this involves only updating the
index file.

However, all the .MYD, MYI and .frm files are duplicated (#sql-*), and
then something happens for quite a bit of time.

Is this related to the fact that I have more indexes in the table, and
those are retained?

I guess MySQL is doing something intelligent, but I did not find a
source that explains the procedure ... what exactly happens.

Gaspar
Thread
dropping primary key - 99%CPUGaspar Bakos10 Jun
  • Re: dropping primary key - 99%CPUDan Nelson10 Jun
    • Re: dropping primary key - 99%CPUGaspar Bakos10 Jun
      • Re: dropping primary key - 99%CPUmos11 Jun
      • Re: dropping primary key - 99%CPUebergen11 Jun