Re: [Devmon-devel] Topological sort

[Buchan M. <bg...@st...>]

On Monday, 20 December 2010 16:51:00 Nelis, Wim wrote:
> Hello,
> 
> when Devmon evaluates the transforms in a template, it uses a recursive
> algorithm to resolve the dependencies between the OIDs. In the patch
> below, the evaluation is divided into two steps. First the order of the
> evaluation of the OIDs is determined using a topological sort. Then, the
> OIDS are evaluated, without recursion, in the order determined in the
> previous step. An added benefit of a topological sort is that it detects
> any circular dependency chains in a simple and robust manner.
> 
> The patch on Devmon below is NOT complete: the implementation for a
> multinode environment is still missing, as I have no means to test it.

Multiple nodes aren't necessary to test it, just a mysql database on a "test" 
devmon box.

> Although it is possible to sort the OIDs just after reading them from the
> database, a better approach is probably to save the sorted list of OIDs in
> the database as well.

I think that should not be too difficult. I will try and take a look at it 
later.

> The patch is published in the hope that someone is both interested and
> willing to extend and test it in a multinode environment. The patch uses
> the "/trunk" Devmon version 187 as the base. It is in use at our site for
> over half a year, without apperent problems. I had the impression that the
> runtime of Devmon was lowered with about 1 second, on a total average
> run-time of about 70 seconds, but after a few days the total average
> run-time was back to it's original value.

So ... we're not sure if it has any real benefit?

Regards,
Buchan