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From Chetan Mehrotra <chetan.mehro...@gmail.com>
Subject Re: [MongoMK] flag document with children
Date Thu, 24 Oct 2013 09:53:16 GMT
I am trying to prototype an approach. Would come up with a patch for
this soon. So far I was going with the reverse approach whereby when I
fetch a node I retrieve some extra child rows [1] in same call to
determine if it has any children.

But given that number of read would far exceed number of writes it
would be better to perform extra update call. I would try to come up
with a patch for this

regards
Chetan
[1] by adding an or clause to fetch node with id say "^2:/foo/.*" to
fetch child node for a parent with id "1:/foo".
Chetan Mehrotra


On Thu, Oct 24, 2013 at 3:08 PM, Thomas Mueller <mueller@adobe.com> wrote:
> Hi,
>
> Yes, you are right. It should be relatively easy to implement (low risk).
>
> Regards,
> Thomas
>
>
> On 10/24/13 10:12 AM, "Marcel Reutegger" <mreutegg@adobe.com> wrote:
>
>>> The disadvantage is, when a node is added, either:
>>>
>>> - then the parent needs to be checked whether is already has this flag
>>>set
>>> (if it is in the cache), or
>>
>>I'd say a parent node is likely in the cache because oak will read it
>>first before
>>it is able to add a child.
>>
>>> - the parent needs to be updated to set the flag
>>
>>that's correct. though you only have to do it when it isn't set already.
>>and
>>the check should be cheap in most cases, because the node is in the cache.
>>
>>regards
>> marcel
>>
>

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