Re: table retrieval in "session" or in "transaction"

On 07/02/2008, Humpolicek <[email protected]> wrote:
>     I am unable to determine when some snmp client begins to read my
> table and when this client finished it's retrieval.

That's pretty much standard for any SNMP MIB implementation.
The agent receives and processes each request independently.
It can't really distinguish between a client that is walking the full
table, and one that is picking out individual items.

  And of course, there's nothing to say that you'll only ever have
one client querying your agent.   It's quite feasible to have several
management clients all trying to walk the same table at the same time.



The usual technique to avoid reading in all the table information for
each request, is to cache an internal copy of the table, and use this
information to process the individual requests.   Then it's just a matter
of walking through this internal table, with no need to interact with
the underlying system every time.

   The Net-SNMP agent toolkit includes a cache helper, designed for
this very purpose.  If you generate your MIB code template using
the command

    mib2c -c mib2c.iterator.conf  -S cache=1   myTable

then this will include the necessary framework for re-loading the
table data whenever it's deemed "too old".
Alternatively, you might want to look at the code generated by

    mib2c -c mib2c.table_data.conf  -S cache=1   myTable

which is probably more efficient, since it doesn't have to walk
through the whole table every time.   The helper knows which
rows are valid, so can go directly to the appropriate one for each
request.


But that's a much more flexible and reliable approach than
trying to recognise when a client is walking the table.

Dave

-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2008.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
Net-snmp-users mailing list
[email protected]
Please see the following page to unsubscribe or change other options:
https://lists.sourceforge.net/lists/listinfo/net-snmp-users