Re: Versioning your Model with NoSQL storage

On 4/2/13 17:38 , Greg Young wrote:
>> In one system I wrote the storage was serialized Java objects (blindingly
>> fast read/write was objective), and the changes between 1.0 and 2.0 were
>> substantial, including aggregate changes. What we did was to serialize the
>> whole database to a single massive XML file, and then use a 2-pass SAX XSLT
>> to transform it into new format, and then chop it up back into the new
>> serialized format.
>
> This works very well on small datasets. If you have a few billion
> items in say riak (128 node cluster) this doesn't work so well :)

For sure.

> There is a secondary problem with this in that this is an "offline" migration.

Yup. For online migration the read-fix thing that Qi4j has works better.

/Rickard



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