Thrift interface mismatch problems.

[Toby White <to...@googlemail.com>]

I'm not sure whether to note this as a bug, since it's an obvious  
PEBKAC with an obvious fix; however, it caused me problems, so I  
thought I'd note it here anyway.

I recently upgraded my hbase server from 0.2.1 to 0.18.0. However, I  
neglected to upgrade the client thrift libraries that my Python  
scripts use.

The result was silent failure - all the scripts carried on as normal,  
apparently writing data to the server without any error (using a  
thrift mutateRow call), but in fact doing nothing at all. I only  
spotted the error some time later when trying to retrieve the data,  
and found that nothing had been written.

Fortunately this was only test data, so there are no disastrous ill  
effects, only the loss of a bit of time debugging the problem, and  
I'll make sure not to do the same thing next time.

I don't know if there are ways to use thrift in a way less likely to  
break on upgrade of the communications protocol, but it would be nice  
if so.

Toby