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From:Rob Wultsch Date:February 9 2010 12:26pm
Subject:Re: Changing innodb_buffer_pool_size on the fly
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On Mon, Feb 8, 2010 at 12:12 PM, Rick James <rjames@stripped> wrote:
> I'm curious -- what will you do with the RAM you take away from InnoDB's
> buffer pool?  (In a dedicated MySQL server, I seen no reason to alter the
> size.)

// I have not read the code.

I think the use case would generally be growing the buffer pool.

Off the top of my head I see several reason:
1. Non-dedicated servers which were started without a buffer pool
parameter. 8MB ain't much and downtime sucks.
2.Dedicated servers with multiple instances of MySQL.Keeping some RAM
in reserve that can be allocated to an instance that is acting up
ain't a bad thing.
3.Dedicated servers which have under allocated ram to the buffer pool
or grown to a point where the value is underallocated. This is not a
bad thing. See http://bugs.mysql.com/bug.php?id=29847 .

However, lets say on a dedicate server the buffer pool has been over
allocated and the server is swapping. Being able to free() memory and
getting out of swap would be quite useful.

-- 
Rob Wultsch
wultsch@stripped
Thread
Changing innodb_buffer_pool_size on the flyElena Kasyanova8 Feb
  • Re: Changing innodb_buffer_pool_size on the flyRick James8 Feb
    • Re: Changing innodb_buffer_pool_size on the flyElena Kasyanova9 Feb
    • Re: Changing innodb_buffer_pool_size on the flyRob Wultsch9 Feb
      • Re: Changing innodb_buffer_pool_size on the flyElena Kasyanova9 Feb
        • Re: Changing innodb_buffer_pool_size on the flyXuekun Hu10 Feb
    • Re: Changing innodb_buffer_pool_size on the flyRick James18 Oct