More or less, yes.
If the requests are from the same client, then you say that there will not be a problem? I guess that is true if you always wait for the response of the first request in order to execute the second. I am not sure if that is a requirement for all Zookeeper client implementations. As for two different clients (which was the case I was thinking about), this seems to be a problem. I will agree that (if clients only have one outstanding request) the two requests are concurrent and either order of execution is considered to be acceptable, but it could be that two different replicas receive the two requests in the same order, but effectively execute them in a different order. In any case, it feels wrong (at least to me) that a getData would succeed when a setACL that prevents it has already been accepted to be processed.


Manos

Mahadev Konar wrote:
Hi Manos, If the setAcl and getdata are from the same client then they are all
handled in order. So you would get an unauthroized exception when you do a
getdata.

If two diff clients do setacl and getdata it might be that the getdata in
your case will succeed before the setacl returns on the first client.

Is that what you meant?

mahadev


On 2/10/09 2:15 PM, "Manos Kapritsos" <ma...@cs.utexas.edu> wrote:

Hi all,

I have a question about the way setACL functions. It seems that the
PreRequestProcessor handles all kinds of requests the same, checks the
validity of the corresponding ACL, and enqueues them to Sync and Final
processors. Maybe I am missing something here, but this behaviour seems
weird. What if a setACL request comes, setting the ACL of a path (e.g. /
) to an IP (e.g. 128.62.32.32) , instead of its old value (e.g. World).
This request will pass the ACL check, and will be enqueued to be
processed by the next processors. Assume that the next request is a
getData("/") from an IP other than 128.62.32.32. If this request is
processed by the PreRequestProcessor before the setACL request is
processed by the FinalRequestProcessor, then it will pass the ACL check
(which it should not, since it came after the setACL request). It seems
that there is a race condition here that should not exist.

Let me know if this is actually the case or I am missing something. I am
using version 3.0.1 of the code.

Thank you,
Manos

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