RE: Can MySQL handle 120 million records?

[Dean Harding]

It's just that the number of rows in a table is stored directly in the
.MYD file (I believe) so a query like "select count(*) from table" will
just return that value, rather than counting all the rows.  It's not
that the functions are "built-in", rather they're *optimized* - a
totally different thing.

Dean.

> -----Original Message-----
> From: JamesD [mailto:jim@stripped]
> Sent: Saturday, 21 December 2002 7:33 pm
> To: mysql@stripped
> Subject: RE: Can MySQL handle 120 million records?
> 
> Jeremy,
> 
> if i run the command
> 
> show tables; on some database
> it returns
> 
> "5 rows in set (0.02 sec)"
> 
> and if, on the same database i run
> the command
> 
> select count(*) from 'table';
> it returns
> 
> +---------+
> | count(*)|
> +---------+
> | 47226322|
> +---------+
> 1 row in set (0.00 sec)
> 
> now, i believe its reasonable to assume
> a CPU must spend more time to count 47 million records,
> than to count 5 tables. This is why I believe
> that many common selects are built-in to mysql in the code
> somewhere. make sense? Its a good idea actually, that building
> in commonly run selects when the process is idling and stuffing
> results into variables that can be called in an instant, saves
> us all time and money...
> 
> Jim
> 
> 
> -----Original Message-----
> From: Jeremy Zawodny [mailto:Jeremy@stripped]
> Sent: Friday, December 20, 2002 3:28 PM
> To: JamesD
> Cc: mysql@stripped
> Subject: Re: Can MySQL handle 120 million records?
> 
> 
> On Wed, Dec 18, 2002 at 08:05:46PM -0800, JamesD wrote:
> >
> > i like mySQL, but it has a long way to go to gain the level of
> > 'confidence' that oracle, db2 or mssql or sybase have when it comes
> > to frontline mission critical stuff.
> 
> Can you explain why?
> 
> > I think it will in time...thats why i stick with it. besides,
> > confidence is often just a synonym for 'knowledge'
> 
> Really?  I tend to see it more like confidence builds with experience
> (and therefore time).  You don't need to know a lot about to become
> confident in its operation.  Many of us don't *really* understand how
> gravity works, but we're quite confident in it.
> 
> > select count(*) from x (0.00 seconds)
> >
> > if you dig into the source, you will probably find this common
> > select is built in and running all the time,
> >
> > and we are all just getting a pre-filled variable
> > returned from the method " select count(*) from (x) "
> 
> Please find it.  I'll bet you money that it's not.
> 
> > I hope someone can prove me wrong...
> 
> I think the burden of proof is on you.
> 
> Jeremy
> --
> Jeremy D. Zawodny     |  Perl, Web, MySQL, Linux Magazine, Yahoo!
> <Jeremy@stripped>  |  http://jeremy.zawodny.com/
> 
> MySQL 3.23.51: up 5 days, processed 219,909,773 queries (441/sec. avg)
> 
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