> From: Todd Lipcon <[email protected]> > If a feature doesn't properly handle error conditions, it shouldn't be > committed, IMO.
This is my concern as well. I had initially given the feature a +1 to get it in so further development can be done, but upon further consideration (and Todd's code review) I'm concerned it won't be useful in practice as currently implemented. Attempting a schema update would require a completely healthy cluster and no failure could occur during that time. In other words, the cluster would have to be quiesced first. That is not practical, so the feature is not useful. My recommendation is to begin adding test cases that test RS and ZK quorum peer failures happening while the schema update is in progress, and insure that failures are handled and the update process recovers and succeeds. Once there is a set of such tests we can evaluate their coverage and introduce the feature. It would still be risky, but there would be some basis for believing it to be practical. Best regards, - Andy Problems worthy of attack prove their worth by hitting back. - Piet Hein (via Tom White) >________________________________ >From: Todd Lipcon <[email protected]> >To: Ted Yu <[email protected]> >Cc: Andrew Purtell <[email protected]>; Subbu M Iyer <[email protected]>; >[email protected] >Sent: Wednesday, September 14, 2011 11:57 PM >Subject: Re: HBASE-4213 > >On Wed, Sep 14, 2011 at 2:51 PM, Ted Yu <[email protected]> wrote: >> Todd/Andy: >> Instant schema change is an important feature. >> >> Can you let us know the criteria for HBASE-4213 to graduate ? >> Does HBASE-4370 have to be implemented ? > >In my opinion, the criteria is the same as any other. Reviewers should >be convinced it doesn't introduce bugs or APIs we don't want to >maintain, and the feature should be usable by ordinary folks. There >should also be sufficient testing including fault scenarios. If a >feature doesn't properly handle error conditions, it shouldn't be >committed, IMO. > >-Todd >-- >Todd Lipcon >Software Engineer, Cloudera > > >
