Problems with weird errors running 0.13

Kevin Smith ksmith at basho.com
Mon Nov 29 17:08:48 EST 2010


Jon - 

I think I can explain the behavior you're experiencing. During work leading up to the 0.13 release the logic around how and when reduce functions are called was subtly changed. The change caused reduce functions to be called with empty input at the end of a job immediately prior to the reduce phase performing re-reduction.

Built-in functions, like Riak.reduceSum, didn't reveal the problem as they contain logic which filters out empty input lists. I've opened a bug (http://issues.basho.com/899) to track this problem. I have isolated a potential fix for it and will commit it for the next release. In the meantime, you can work around the problem by coding your reduce functions to ignore empty inputs.

--Kevin
On Nov 29, 2010, at 10:08 AM, Jon Brisbin wrote:

> 
> On Nov 29, 2010, at 8:59 AM, David Smith wrote:
> 
>> On Mon, Nov 29, 2010 at 7:43 AM, Jon Brisbin
>> <jon.brisbin at npcinternational.com> wrote:
>>> I'm working on the Spring Data and Grails Gorm support for Riak and I'm seeing some problems running my tests against Riak 0.13. I don't see these problems when running 0.12.
>> 
>> Can you elaborate on the problems you're seeing, please?
> 
> There's two problems I'm seeing, one is with map/reduce, the other is that the server will crash under the load the tests put on it (I'll send a separate email with steps to reproduce).
> 
> Here's an example of a problem I'm seeing in M/R (from an earlier message):
> 
> I'm seeing some weird behavior with map/reduce in 0.13 versus 0.12 and I'm not sure what's going on here. I'm hanging out in the chat room right now trying to find out, but basically, if I run this test case against 0.13 I get a completely different result than what I get in 0.12:
> 
> http://pastie.org/1320874
> 
> In 0.12, I get [1] in 0.13 I get [2].
> 
> The output I'm logging looks like this for 0.12:
> 
> 11/23/2010 (13:39:47): map={"bucket":"test","key":"test","vclock":"a85hYGBgzGDKBVIsTE+lb2UwJTLmsTLUTEk4xpcFAA==","values":[{"metadata":{"Links":[],"X-Riak-VTag":"5qaBBTXfdEQUyCBTDRRIQ7","content-type":"application/json","X-Riak-Last-Modified":"Tue, 23 Nov 2010 19:39:40 GMT","X-Riak-Meta":[]},"data":"{\"test\":\"value\",\"integer\":12}\n"}]}
> 11/23/2010 (13:39:47): reduce=[1]
> 
> And this in 0.13:
> 
> 11/23/2010 (13:46:52): map={"bucket":"test","key":"test","vclock":"a85hYGDgzmDKBVIsjDI+7RlMiYx5rAz9ExKO8UGE2ZqTWGZL10AlRCfBJVgYLplNxhQGqmeMbn4EldBEUs/k7LodUxionils9l2oRBGy+cHJ7zGFgeqZk3faQCVOT0aoZzG1PohFmNWr8CxUWGUaijFv+lYiS2QBAA==","values":[{"metadata":{"Links":[],"X-Riak-VTag":"If4qIgutNTerbEmxiKLhR","content-type":"application/json","X-Riak-Last-Modified":"Tue, 23 Nov 2010 19:46:44 GMT","X-Riak-Meta":[]},"data":"{\"test\":\"value\",\"integer\":12}\n"}]}
> 11/23/2010 (13:46:52): reduce=[]
> 11/23/2010 (13:46:52): reduce=[1,0]
> 
> I tried Homebrew (OS X 10.6) and the OS X download packages of both versions.
> 
> Jon Brisbin
> Portal Webmaster
> NPC International, Inc.
> 
> 
> 
> 
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