Re: RAM and caching

[Corin Hartland-Swann]

Hi there,

On Tue, 23 Mar 1999, matthew mcglynn wrote:
> I'd like to be able to cache much or most of this in RAM
> to speed queries, as this server just keeps getting busier.
> My question is this: what is the algorithm for determining
> how much RAM is necessary to slurp this db into memory ?
> What I'm thinking is that there may be some unknown factors
> that make this answer more complicated than "you need just
> under a gig of RAM".
> 
> For example, are the disk files compressed in any way? Or,
> are the RAM copies compressed ? If multiple mysqld threads
> open a table, does it occupy more memory than if only a single
> thread opens the table ?
> 
> The host OS is Linux 2.0.36. Right now we're using
> v. 3.22.12-beta, although we'll be upgrading to whatever
> the current binary release is in a few days.

Somewhat off-topic, but you will have difficulty using a whole 1G of RAM
with Linux 2.0.x - something to do with reserved bits of RAM. There are
various issues covered in one of the HOWTO's (regarding memory).
Linux 2.2.x handles up to a bit less than 2G though, iirc.

Regards,

Corin

/---------------------------------------------\
|                                             |
|      Corin Hartland-Swann - Webmaster       |
|                                             |
+---------------------------------------------+
|                                             |
|      The International Lyrics Network       |
|                                             |
|           http://www.lyrics.net/            |
|                                             |
| mysql 3.22.20 - apache 1.3.4 - perl 5.00505 |
|                                             |
\---------------------------------------------/