MySQL proxy query duplication

[Chris Vivid]

Hi there!

MySQL proxy seems to be heavily used for R/W type splitting applications. I wish to duplicate queries to two servers and only return data from one of them.

I realise that MySQL proxy handles load balancing type behaviour with the following syntax:
--proxy-backendaddresses
and if there are multiple backendaddresses then it will start to load balance between them.

How can I get proxy to do what I need? Any tips for writting the Lua script which will split the query two masters and only return the result from one?

The two masters should not be aware of each others presence - otherwise I would have used standard replication.

Thanks for any input!