[Dxspider-support] SHOW/DX ignoring old spots

[Dirk Koopman]

Ooo err...

That's an interesting idea. Have you done any benchmarks to see what the
difference is?

Firstly, just to confirm:-

set/var $Spot::maxdays = 1000

does what you say you want.

However, I really would not recommend it unless you have a much faster
machine that I have (which isn't too difficult, but it likely only to be
twice as fast). 

There has to be a limit because the spot files are searched
sequentially, backwards in time, and in perl (actually this is a slight
over-simplification but is a good working explanation).

This is reasonably quick but still noticable. As the software is single
threaded, if it is searching for DX Spots, it isn't servicing incoming
data (TCP connections). The reason a limit was put on it was to limit
the length of time an (unsuccessful) DX Spot search could take. This is
also why there is a finite limit on the maximum of spots you can ask for
as well (set/var $Spot::maxspots = 100).

If there are less than the no of spots that you ask for (and this is <=
$maxspots) then that will cause $maxdays no of spot files to be
searched. Unfortunately, the more common the thing is that you are
looking for, the quicker the search returns.

There is a similar "problem" with searching log files.

The point of using the:-

  day <number>    - starting <number> days ago
  day <from>-<to> - <from> days <to> days ago
      <from>/<to>

constructions is that if it wasn't seen in the last 100 days, then you
would have to use one of the above to go further back.

Personally, I don't think this is a big deal. The only people that are
actually, seriously, interested in spot data that old are not normally
bothered by using the above arrangement. In some cases it actually helps
to narrow down (for) when they are looking. A bit of user education
seems appropriate here.

My *strong* recommendation is that you do not increase these defaults by
much (no more than double). The default values were chosen with some
care and with a particular tradeoff in mind. 

Afterall we don't want to suffer the performance problems that some
other software (apparently) has with sh/dx, now do we?

Dirk G1TLH


On Thu, 2005-05-05 at 22:22 +0000, Darren G0TSM wrote:
> Just one thing to remember, the higher the maxdays the longer a SH/DX 
> search will take when it doesnt find what you are looking for.
> I speed things up in windows by keeping the spot data in the disk cache by 
> adding a line in the crontab file
> 
> 3,7,12,17,22,27,32,37,42,47,52,57 * * * * run_cmd('SH/DX XYZ0XYZ')
> 
> This searches for a call which is never found so looks through all the spot 
> data back to your maxdays limit.
> The downside of this is that i guess a glitch in the power could corrupt 
> the files?, but i've never had any problems.
> 
> Darren G0TSM/GB7EDX
> 
> 
> At 21:12 05/05/2005, you wrote:
> >Sorry !!!
> >My mistake on cut and paste...
> >
> >...a line similar to the following:
> >
> >set/var $Spot::maxdays = 1000
> >
> >73 de Luigi, ik5zuk
> >
> >----- Original Message -----
> >From: "Robert Chalmas" <rchalmas at users.ch>
> >To: "The DXSpider Support list" <dxspider-support at dxcluster.org>
> >Sent: Thursday, May 05, 2005 10:52 PM
> >Subject: Re: [Dxspider-support] SHOW/DX ignoring old spots
> >
> >
> > > Hi Arnold,
> > >
> > > Congratulations for finding the solution to my problem !
> > > I never had the idea to check this file.
> > >
> > > I tried on my test node to change $maxdays to 1000 before starting
> > > the cluster software and it worked OK.
> > > I tried this also on the real node and did a load/cmd_cache but
> > > no result. Obviously, a restart of the node is needed, but I won't
> > > do it now only for this reason.
> > >
> > > Thanks and vy 73's de            Robert - HB9BZA
> > >
> > > > I don't think it's a bug, if I understand it well those parameters are
> > > > defined in /spider/perl/Spot.pm
> > > >
> > > > (search for $maxdays)
> > > >
> > > > Like always if you want to make changes copy Spot.pm to /spider/local
> > > > and  make the changes in /spider/local/Spot.pm
> > >
> > > --
> > > Robert CHALMAS, PO Box 1225, CH-1227 Carouge/GE, SWITZERLAND
> > >     email:        rchalmas at users.ch    AX-25: HB9BZA @ HB9IAP
> > > homepage: http://rchalmas.users.ch
> > >
> > > _______________________________________________
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> >
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