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From:Paul DuBois Date:January 11 2003 4:19am
Subject:Re: Enabling Cache feature in MySQL 4
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At 18:22 +0100 1/10/03, Blaster wrote:
>Happy as I was, I pulled out a test box, installed Linux Debian on 
>it, downloaded MySQL 4 on it, everything worked smooth, now I wanted 
>to enable
>the cache feature, but it didn't let me! I want the change to be 
>permanent, so I looked up the doc pages at, and found info 
>about the
>/etc/my.cnf file, which I created and put in:
>set-variable = query_cache_size = 67108864
>The MySQL deamon was restarted, but when I checked the run-time 
>variables with SHOW STATUS, query_cache_size was still set to 0? I 
>even tried

That's odd, since it's SHOW VARIABLES that displays query_cache_size.
SHOW STATUS displays the Qcache_% variables.  But anyway, the syntax
looks okay; I use a similar line on my laptop:

set-variable = query_cache_size=1M

(1M = 1 megabyte)

>rebooting the entire machine after the changes to my.cnf, but it 
>wouldn't work -- as if MySQL ignored my file? Now, I was thinking, 
>either MySQL
>reads the setting from somewhere else in my system, but since I 
>cannot find a "config file" variable in SHOW STATUS, I cannot find 
>out from where?
>Another possibility is that it does read it, but for some reason 
>ignores it, or even worse, reads a 2nd config file and the setting 
>is overriden?

Possibly.  mysqld --help will show you the option files that it reads,
and mysqld --print-defaults will show you the option settings that it's
picking up from option files.

>Now, this was quite odd I thought, so I tried to set the cache 
>manually with a query,
>"SET GLOBAL query_cache_size=67108864"
>and that worked like a charm, it even updated "query_cache_type" to 
>1, which, according to the manuals mean ON.
>Now, I was wondering if any of you have a hint on what might be wrong?
>Also, as a little sidenote, I'm kinda wondering, what is a _decent_ 
>size for the Cache buffer? is 64 Mb enough? I'm getting an upgraded 
>server aswell, it
>will be 800 Mhz and have 256 MB of ram, this box will be 100% MySQL 
>and I'll leave the Webserver on the old 400 Mhz. Any other hints on 
>optimizing is appreciated!

I only use 1MB, but I don't have a lot of repeated huge queries.

>Sorry if this post got too long, this is my first time posting on 
>this list. Take it easy on my poor english skills =)

Enabling Cache feature in MySQL 4Blaster10 Jan
  • Re: Enabling Cache feature in MySQL 4Paul DuBois11 Jan
RE: Enabling Cache feature in MySQL 4Andrew Braithwaite11 Jan