[Haskell-cafe] Re: sizeFM type

[S. Alexander Jacobson]

On Tue, 27 Apr 2004, Tomasz Zielonka wrote:
> On Mon, Apr 26, 2004 at 08:43:44PM -0400, ajb at spamcop.net wrote:
> > I would note, in addition, that they don't have that many pages indexed
> > on a single machine.  Almost nobody has a database with that many records
> > on a single machine, even those who have clusters of 64 bit machines.
>
> It seems I qualify as almost nobody, cause I've had a database with more
> than 2^34 records on a single IA32 machine. However, I wouldn't ever
> think of loading the entire database to RAM.

Why not?  Its only 17gb.  If you are doing any
substantive volume of transactions on that
database* you may be better off storing the
database in memory than buying the multiple CPUs
and reliable RAID arrays you need to serve it off
disk.

A Dell PowerEdge 4600 w/ 24gb of memory and a
write-caching controller w/ 6 36GB harddrives
(RAID0 state,logging,status) costs around $34k.
<http://www1.us.dell.com/content/products/compare.aspx/tower?c=us&cs=555&l=en&s=biz>
Using e.g. a Prevayler style in memory logged data
structures** you may be able to serve >100,000
queries/second. (see e.g.
<http://www.prevayler.org/wiki.jsp?topic=ScalabilityTestResults>)

To achieve just 500 queries/second using MaxDB
(SAP-DB from MySQL) requires apparently 61!! App
servers.
(<http://www.mysql.com/products/maxdb/benchmarks.html>)
Calculating the cost of this much hardware is left
as an exercise for the reader, but, even ignoring
the hardware costs here, you are also paying for
rackspace and system administration to keep this
many servers operating.

-Alex-

* OTOH, if this is just your personal mail archive
then nevermind :- )

** Finishing off a Haskell variant of this concept
that also handles side-effects correctly right
now.  It is part II of the rdbms, appserver,
web/mail server triad that I plan to use for a
variety of different web apps.

_________________________________________________________________
S. Alexander Jacobson                  mailto:me at alexjacobson.com
tel:917-770-6565                       http://alexjacobson.com