Maximum number of updates in a single transaction
Mark_Andrews at isc.org
Sat Feb 11 01:30:12 UTC 2006
> Mark Andrews wrote:
> >>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
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