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From "Shelley, Ryan" <Ryan.Shel...@disney.com>
Subject Re: Create nested paths
Date Thu, 01 Mar 2012 19:17:03 GMT
Ok, I tried this with the Op.create and found that it will throw a
KeeperException on the first path that doesn't exist. It doesn't return
back an OpResult with an "error" type. I can still use this, and just
catch the exception and create the node in the exception, but I was under
the impression that I could do this in two trips. One trip to get back a
list of OpResults from the check that would inform me if the path existed
or not, and a second trip to create all the paths that don't exist (and as
a note, the CheckResult object doesn't include the path, so I have to
infer it from the order of my original list of paths used to create the
multi-check).

-Ryan

On 2/29/12 7:16 PM, "Ted Dunning" <ted.dunning@gmail.com> wrote:

>On Wed, Feb 29, 2012 at 7:04 PM, Marshall McMullen <
>marshall.mcmullen@gmail.com> wrote:
>
>> Yes, Ted's right. The multi has to fail as that's part of the contract
>>it
>> guarantees.
>>
>> The only thing you could do, which will significantly narrow the race
>> condition, is as you're *building *the multi, check if the path already
>> exists. If so, then don't add the create op for that path into the
>>multi.
>> Of course this may not work in every situation, but we use that
>>approach in
>> many code paths and it works well.
>>
>
>Another approach is to compose one multi with Op.exists() for each level
>so
>that you find everything you need, then create another with the correct
>Op.create() operations.  That gets the problem down to two server
>round-trips but still has the race condition.


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