As a part of the exciting series of events (long story...) around our riak cluster this week, we switched over to riak-pipe mapreduce. Usually, when a node is down mapreduce times shoot through the roof, which causes slow behavior and even timeouts on the API. Riak-pipe changes that: our API latency for mapreduce-heavy requests like feeds and comments fell from 3-7 seconds to a stable 600ms. Still high, but at least tolerable.
[Update] I should also mention that riak-pipe MR throws about a thousand apparently random, recoverable errors per day. Things like
map_reduce_errorwith no explanation in the logs, or
{"lineno":466,"message":"SyntaxError: syntax error","source":"()"}when the source is definitely not "()". Still haven't figured out why, but it seems vaguely node-dependent.
Hi, Did you finally fix this error? I’m having the same issue with riak-1.0.1.
Regards, Jose
Correction: riak-1.0.0
Jose, I haven’t figured it out yet, but I think it’s something to do with deleted objects. You may want to try checking metadata[‘X-Riak-Deleted’].