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From Cameron McKenzie <mckenzie....@gmail.com>
Subject Re: cache recipes
Date Fri, 18 Nov 2016 00:25:14 GMT
I was thinking about whether it's worth adding to the TreeCache but I don't
think that the write thorough requirement is a common use case.

Also it wouldn't work for sequential nodes.

On 18 Nov 2016 10:24 AM, "Scott Blum" <dragonsinth@gmail.com> wrote:

> Correct, there's no way to write-through TreeCache without a shim of some
> kind.
>
> On Thu, Nov 17, 2016 at 5:58 PM, Cameron McKenzie <mckenzie.cam@gmail.com>
> wrote:
>
>> Hey Scott,
>> This would mean blocking the main thread until the event arrives though
>> yes?
>>
>> I think that Hendrik was taking about having the cache updated as soon as
>> the write is acknowledged by ZK, rather than waiting for the watcher to
>> fire.
>>
>> On 18 Nov 2016 9:47 AM, "Scott Blum" <dragonsinth@gmail.com> wrote:
>>
>>> You can also just listen for TreeCache events and wait for your change
>>> to come through.
>>>
>>> On Thu, Nov 17, 2016 at 3:18 PM, Hendrik Haddorp <
>>> hendrik.haddorp@gmx.net> wrote:
>>>
>>>> Thanks, that was a pretty fast answer! Not quite what I had hoped for
>>>> but at least now I know that I was right that I have to handle this myself
>>>> :-)
>>>>
>>>>
>>>> On 17.11.2016 21:13, Cameron McKenzie wrote:
>>>>
>>>> Hey Hendrick,
>>>> The recipes don't treat local updates any differently to remote
>>>> updates. The cache will get updated when the cursor client receives a watch
>>>> event from Zookeeper.
>>>>
>>>> So your assertions are correct. The caches provide eventual
>>>> consistency. If you need to ensure that there are no dirty reads between
>>>> when you write locally and when you read from the cache you would need to
>>>> wrap the cache in some manner.
>>>>
>>>> Cheers
>>>>
>>>> On 18 Nov 2016 7:06 AM, "Hendrik Haddorp" <hendrik.haddorp@gmx.net>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I'm trying to use a cache recipe, like the TreeCache. The cache itself
>>>>> works just fine but what I don't understand is how I'm supposed to handle
>>>>> locally triggered updates correctly. I can start the TreeCache and using
>>>>> the events I know when it is initialized but what if I delete a child
node
>>>>> or update a node for example? If I read the data out of the cache before
I
>>>>> get the corresponding update events I get old data. As there doesn't
seem
>>>>> to be an invalidation mechanism I seem to be required to track outstanding
>>>>> updates. Or am I missing something?
>>>>>
>>>>> regards,
>>>>> Hendrik
>>>>>
>>>>
>>>>
>>>
>

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