[Xastir-Dev] Short list, stable release, then Xastir-2 development?
Jerry Chamberlin
jerryc at netlab.org
Thu Mar 13 18:42:16 EST 2003
I disagree, make it XASTIR-3 , I never trust an even numbered product.
2.0 is buggy
2.1 they try to fix
2.2 debug code time
2.3 stable
On Thu, 13 Mar 2003, James Jefferson wrote:
>
> > > My thoughts are that for starters, just the APRS data points received. It
> > > might be helpful to ask Steve Dimse what his database fields are, since
> > > he has plenty of experience in a SQL database of APRS data.
> >
> > We have an Xastir user that has a bit of experience there as well
> > don't we? James?
>
> Sure. I'm databasing ~ 2 million packets a day. Running a database with about
> 60 queries a second 24/7.
>
> I don't have time today to write too much in depth. But here are the issues I
> see:
>
> Indexes, Indexes, Indexes! If you ever do a query that can't take advantage of
> an index, then the system is as good as dead. With the overhead of the
> databases and normalization between tables, you're looking about more than a
> 100 megabytes of data per day. (Heck, the raw stream is at least 50 megabytes
> a day). If you have to do a table scan off of disk (as is the case with a
> machine with not a lot of memory) this starts taking real time.
>
> Figure out what queries you are going to do, and design your tables
> accordingly. For example, on aprsworld.net there is a lastposition table that
> is relatively small (<5 megabytes) and then a full position table that has
> all positions in the database. XAstir would probably want a lastposition
> table, then another table for all of the positions that need to be shown on
> screen.
>
> Look at the overhead of triggers in Postgres. You may find it nescessary to
> have the parser / inserter daemon handle triggering. In aprsworld.net's
> parser it can fork() a program based on the callsign and SSID of the packet
> it has just inserted. On linux, a signal might be a good way of doing
> triggers. Dunno about how fast other *nixes handle signals.
>
> All for now.
>
> -Jim
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