Maximum number of updates in a single transaction

[Mark Andrews]

> Mark Andrews wrote:
> 
> >>Hi,
> >>
> >>We are implementing a new service that requires a substantial number 
> >>of dynamic updates to be performed on a zone. We are talking of 2K 
> >>updates in a single dynamic update transaction.
> >>
> >>We made some tests with Bind 9.3.2 by sending 60 domain updates in a 
> >>single transaction (TCP) and everything works correctly.
> >>
> >>RFC2136 specify a 16 bit limit to UPCOUNT section in the header, so I 
> >>assume that the limit of updates that I can send on a single 
> >>transaction is 2^16.
> >>
> >>What is your recommendation of the maximum number of updates in a 
> >>single transaction?
> >>
> >>I believe that ISC makes validation tests with each BIND release. How 
> >>many dynamic updates are sent in the ISC's validation tests?
> >>
> >>Thank you.
> >>
> >>
> >>
> >>Gustavo Lozano
> >>NIC Mexico (ccTLD .mx)
> >>    
> >>
> >
> >	The limitation is the size of the DNS message.  A individual
> >	message can be up to 65535 bytes.
> >
> Right, which implies that the real-world limit on number of updates in a 
> transaction is going to be far less than 65535 (since each update takes 
> at least several bytes), and is going to depend on a number of factors, 
> such as: whether and/or how many prerequisites there are, the length of 
> the names/RDATAs involved, the extent of label compression, etc.
> 
> One question that comes to my mind is: does BIND support sending 
> multiple UPDATE transactions over the same TCP connection? Seems like 
> there is nothing to forbid this in the RFCs and the precedent has 
> already been set in the case of AXFR...

	Actually there is.  Updates are atomic.  You can't sent two
	updates and have a atomic transaction.
 
>                                                                          
>                                                       - Kevin
> 
> 
> 
> 
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org