We use this in our solutions and search hundreds of millions of routes
with it in 2-3 ms. It works very well, to say the least, because it
is an approach that allows application of complex business logic
(using stored procedures) to the results, something which is much
harder with a more primitive (if faster) in-memory structure. Best of
all, it is specifically designed to deal with the problem of variable-
length prefixes, so many of the prefix length constraints and/or
homogeneity requirements of other routing and LCR engines are
eliminated.
It is not possible to say whether a database-backed structure is
loaded "from memory"; this is a gross oversimplification of a very
complex issue. Clearly, an RDBM cannot load all data into heap;
there is plenty of demand-loading of data from disk. RDBM caching,
filesystem and I/O caching, disk caching, etc. all play a big role in
what the result will actually look like from a median performance
perspective.
--
Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/
On Sep 6, 2010, at 12:06 PM, Daniel-Constantin Mierla
<mico...@gmail.com> wrote:
Hello,
On 9/6/10 6:01 PM, Henning Westerholt wrote:
On Monday 06 September 2010, anthony thomas wrote:
Yes, Indeed we are thinking in using postgres (we already use it
for our
backoffice databases).
This sencente confuses me a little bit:
Hello Anthony,
> "some database which supports proper prefix matching (i think
postgres is
able to do this)"
Once the db is loaded, the prefix matching is done in memory, right?
well, i think this depends on the database configuration and memory
setup of
the machine, but normally this is what you want. I was referring to
the fact
that in my experience one not insert complete number ranges in the
database
but certain prefixes, and then do a longest prefix match to find
the optimal
route. But of course you could do also something like this with
some SQL.
And I am not following you here:
"with some queries in the script instead of a custom module?"
I was referring to the setup you just described, use a standard DB
with the a
module like sqlops instead of something more specialized, e.g. cr.
For postgresql, here is a link to follow for more details:
http://prefix.projects.postgresql.org/
Cheers,
Daniel
--
Daniel-Constantin Mierla
http://www.asipto.com
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