[OSM-talk] Why isn't any XAPI server available ?

Nic Roets nroets at gmail.com
Sat Feb 19 11:40:29 GMT 2011


Let me just explain what I see as the major performance bottleneck
with and API implementation: Disk seeks. A typical computer can
perform a million calculations while waiting for the disk to fetch a
few bytes. So a good data structure that can answer most map (bbox)
calls with a single disk seek is what is needed. (Not a debate on the
best programming language). I have ideas how to do that if anyone is
interested. But I willing to wait and see what Ian comes up with.

--
I'm learning Java right now and I find the array handling quite
peculiar. For storing arrays of dynamic size, I use ArrayList<>. The
only way to index the elements are with the get() method. Compare that
with STL where you can address vectors with the normal [] operator.

On Sat, Feb 19, 2011 at 9:46 AM, Anders Arnholm <anders at arnholm.se> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> 2011-02-18 22:47, David Murn skrev:
>> Is there any language slower or more resource intensive than java?
>
> Yes, there are many, Java have is strengths and down sides, Java as any
> language have it's strengths and down sides. Speed in Java can be much
> better that C, C++ or even hand optimized Assembler. It can also and
> java's weak sides, for performance, is it's dependence on garbage
> collection. That even is proved mathematically be a more efficient way
> of handling memory allocations tends to do the memory handling at for
> the user bad times.
>
> And real time performance in almost all applications have very little
> with the language to do, but with the chooses of algorithms and
> data-storage chosen for the application.
>
>> currently, in the world), then who cares about java, why isnt it written
>> in optimized C or some other similarly lowish level language, rather
>> than java?
>
> There can be a 1000 reasons, and all valid.
> A good team knowing java but not c.
> C make to much time go into development compared to an object oriented
> language.
> C have no good api's to connect to the other services around.
> The bottle neck is not at all in the code for the service but in stuff
> around it.
> When is comes to error's in the code, web, net servers in java are as
> possible to break, using java is not a safe way to make sure the code is
> correct. It still need to be planned and safe for internet usage. The
> typical safety problems thou differ because different things are hard
> ans easy in the two language families.
>
> Just a few random morning thoughts.
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.10 (GNU/Linux)
> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
>
> iEYEARECAAYFAk1fdUwACgkQtbR3SXmySrdAnACgrSQlpvvBNqtT32RlIGBssqMO
> npcAoKrP8LY3syoJf3lKl4VdZz5yttkK
> =EVqp
> -----END PGP SIGNATURE-----
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>
> _______________________________________________
> talk mailing list
> talk at openstreetmap.org
> http://lists.openstreetmap.org/listinfo/talk
>



More information about the talk mailing list