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From:Camilo Uribe Date:September 23 2010 5:31pm
Subject:Re: There is a ram limit?
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On Thu, Sep 23, 2010 at 1:21 AM, Johan De Meersman <vegivamp@stripped> wrote:
> On Thu, Sep 23, 2010 at 12:39 AM, Camilo Uribe <camilo.uribe@stripped>
> wrote:
>> On Fri, Jul 9, 2010 at 12:03 AM, Johan De Meersman <vegivamp@stripped>
>> wrote:
>> > This will mostly depend on your OS, really. Assuming you're running a
>> > 64-bit
>> > flavour of *nix on that box, I don't think you have to worry.
>> Linux on 64-bits.
> Yes, but is the Linux (and your MySQL) itself also 64-bits ? :-p You *can*
> use all of your ram on a 32-bit linux with the Bigmem trick, but that
> introduces quite a bit of overhead, and doesn't remove the per-process
> limit. A 32-bit MySQL will simply not be able to address all that memory,
> even on a 64-bit OS.

Linux and MySQL of 64-bits:

uname -a
Linux blade2 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64
x86_64 x86_64 GNU/Linux

file /usr/local/mysql/bin/mysqld
/usr/local/mysql/bin/mysqld: ELF 64-bit LSB executable, AMD x86-64,
version 1 (SYSV), for GNU/Linux 2.4.0, dynamically linked (uses shared
libs), for GNU/Linux 2.4.0, not stripped

>> The default installation will use all the ram it needs or do I have to
>> configure something else?
> The default setup will use all the RAM if it needs to - but it will do so by
> allocating per-connection buffers, the default shared pool sizes are rather
> conservative.
> For MyISAM you will need to tune query cache, key cache, read buffers, sort
> buffers et cetera;

Thanks, I will look in High Performance MySQL and the mysql manual about them.

By the way the server has all by default, so it use MyISAM.

> for InnoDB you'll make a good start by allocating a large
> chunk to the buffer pool. It may also (or may not, depending) be beneficial
> to leave some ram for the OS' buffer cache, which caches filesystem blocks
> and thus saves on raw reads.
> More exact tuning pointers are best had by observing your database's
> behaviour using a trending tool like Cacti or Munin.

I'm going to install Better Cacti Templates

> I've said it before and
> I'll say it again, my three favourite tuning resources are a) the online
> docs,

The mysql manual?

> b) Baron & C°'s book High Performance MySQL

I'm reading it

> and c) the Performance
> Tuning course.

I didn't knew about this course, I will tell in my job about it and
see if they want to send me.

> With the number of parameters you can tweak on a MySQL, it's
> hard to give more than basic tips without hand-on experience with the
> system.

Thanks I'm going to look the things you said and come back later with
a little more of experiencie and precise questions

> --
> Bier met grenadyn
> Is als mosterd by den wyn
> Sy die't drinkt, is eene kwezel
> Hy die't drinkt, is ras een ezel
There is a ram limit?Camilo Uribe9 Jul
  • Re: There is a ram limit?Johan De Meersman9 Jul
    • Re: There is a ram limit?Camilo Uribe23 Sep
      • Re: There is a ram limit?Johan De Meersman23 Sep
        • Re: There is a ram limit?Camilo Uribe23 Sep