[rrd-users] Re: fetch & resolution

[Matthew Bostwick]

On Sun, 29 Apr 2001, Alex van den Bogaerdt wrote:

> Matthew Bostwick wrote:
> >
> >
> > However, I think you and I were talking about different things.
>
> no we're not.  There is no such limit.
>
> > I was refering to the rrdtool fetch program not as to the database
> > limitations.  After reading your above comments, it seems pretty
> > clear that there are fetch limitations.  If there weren't
>
> There is no such limit.  There probably is *some* limit but it is
> not anywhere near 600 rows.
>
> > limitations, the fetch commands bellow would work, right?  Here's a snip
> > of some stuff we talked about before...  I was talking about the same
> > subject.
> >
> > > You try to fetch (988441200-986112000)/300 = 7764 rows.  How many rows
> > > does your database have for the 5-minute RRA ?  Suppose you only have
>
> How many rows does your database have for the 5-minute RRA ?   600?
> If you have only 600 rows, *you* *cannot* *fetch* *more* *rows*.
>
> > > 600 rows (the default if you use MRTG-like RRDs), you can only ask for
> > > 600*300 = 180000 seconds worth of data in a 300-second resolution.
> > > Any more and RRDtool will automatically override your resolution
>
> You can only query if it's in the database.  If it is not in the
> desired RRA, the RRDtool programs (including but not limited to fetch)
> will use another RRA.  This *is* what's happening to you.  This is
> not a fetch problem, it is no problem at all.  The limitation is in
> the database itself.  Not in the program, in the database.  This is
> user defined.
>
> > > No offence, but creating yet another webpage which isn't read anyway
> > > is the last thing I'm going to do.  From the rrdtool manual page:
>
> And this is where I get lost.  The snippet I included talked about
> just what you don't understand.  You deleted it ?!?
>

Hey Alex!

Thanks for spending some time today with me.   Here's that snipit of logic
you sent earlier.

"
    "It works like this: If you want to store 1000 values
     in 5 minute interval, rrdtool will allocate space
     for 1000 data values and a header area."
[...]
    "This automatically limits the history to the last 1000 values."
"

Okay, here's a dumb question.  How do I figure out how many rows there
are in a give rrd data file?  It doesn't seem like I can dump by row, but
just by date.  Heck I'd dump all and stick it into an array, if I could do
that.

Thanks for helping me out.  I guess I was clueless all along while writing
up everything.

--Matt


--
Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://www.ee.ethz.ch/~slist/rrd-users
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi