My bad, should have asked about the version. Sent from my iPhone
On Dec 6, 2011, at 2:31 AM, Dmitriy Ryaboy <[email protected]> wrote: > You guys are talking about different versions of Pig. > > Parallelism is filled in using the heuristic Prashant describes in Pig > 0.8 or later. The behavior Ayon is seeing is consistent with Pig 0.7 > and earlier. Ayon, what's the Pig version? If it's less than 0.8, > please try to upgrade. If you are stuck on Amazon's EC2 (they are > still running 0.6), please contact them and ask them to upgrade. > > D > > On Tue, Dec 6, 2011 at 1:13 AM, Prashant Kommireddi <[email protected]> > wrote: >> Also, check "pig.exec.reducers.bytes.per.reducer" which should be set to >> 1000000000 and "pig.exec.reducers.max " which should be set to 999 by >> default. >> >> If those are fine too, may be you could set "default parallel" or use the >> PARALLEL keyword to manually set # of reducers. >> >> Thanks, >> Prashant >> >> On Tue, Dec 6, 2011 at 1:07 AM, Prashant Kommireddi >> <[email protected]>wrote: >> >>> What does the "HDFS_BYTES_READ" on JobTracker for this job say? >>> >>> -Prashant >>> >>> >>> On Tue, Dec 6, 2011 at 12:59 AM, Ayon Sinha <[email protected]> wrote: >>> >>>> The total input path size is ~60GB. That is 1023 files of appx. 64MB >>>> each. Total Map output bytes was 160GB. So why was there 1 reducer? Help me >>>> understand. >>>> >>>> -Ayon >>>> See My Photos on Flickr >>>> Also check out my Blog for answers to commonly asked questions. >>>> >>>> >>>> >>>> ________________________________ >>>> From: Prashant Kommireddi <[email protected]> >>>> To: Ayon Sinha <[email protected]> >>>> Cc: "[email protected]" <[email protected]> >>>> Sent: Tuesday, December 6, 2011 12:26 AM >>>> Subject: Re: How to see Pig MapReduce plan & classes >>>> >>>> Yes, when neither default parallelism nor PARALLEL is used Pig uses >>>> "pig.exec.reducers.bytes.per. >>>> reducer" to determine number of reducers. This is set to ~1GB -> which >>>> means 1 reducer per ~1GB of input data. >>>> >>>> You can try hadoop fs -dus <filepath> and you would see the size is less >>>> than 1GB. >>>> >>>> >>>> On Mon, Dec 5, 2011 at 11:59 PM, Ayon Sinha <[email protected]> wrote: >>>> >>>>> I have 1023 gz files of < 64MB each. >>>>> I think I see the reason in the log :( >>>>> >>>>> 2011-12-05 23:11:20,315 [main] INFO >>>>> >>>> org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.JobControlCompiler >>>>> - Neither PARALLEL nor default parallelism is set for this job. Setting >>>>> number of reducers to 1 >>>>> >>>>> -Ayon >>>>> See My Photos on Flickr <http://www.flickr.com/photos/ayonsinha/> >>>>> Also check out my Blog for answers to commonly asked questions.< >>>> http://dailyadvisor.blogspot.com> >>>>> >>>>> ------------------------------ >>>>> *From:* Prashant Kommireddi <[email protected]> >>>>> *To:* [email protected]; Ayon Sinha <[email protected]> >>>>> *Sent:* Monday, December 5, 2011 11:56 PM >>>>> *Subject:* Re: How to see Pig MapReduce plan & classes >>>>> >>>>> What is the total size of your input dataset? Less than 1GB? Pig spawns >>>> 1 >>>>> reducer for each gigabyte of input data. >>>>> >>>>> -Prashant Kommireddi >>>>> >>>>> On Mon, Dec 5, 2011 at 11:53 PM, Ayon Sinha <[email protected]> >>>> wrote: >>>>> >>>>> Hi, >>>>> I have this script whose stage 1 has n maps where n = # of input splits >>>> (# >>>>> gz files) but has 1 reducer. I need to understand why my script causes 1 >>>>> reducer. When I think about how I'd do it in Java MapReduce, I dont see >>>> why >>>>> there would be a single reducer in stage 1. >>>>> >>>>> register /home/ayon/udfs.jar; >>>>> >>>>> a = load '$input' using PigStorage() as (a:chararray, b:chararray, >>>> c:int, >>>>> d:chararray); >>>>> >>>>> g = group a by (a, b); >>>>> >>>>> g = foreach g { >>>>> x = order $1 by c; >>>>> generate group.a, group.b, x; >>>>> }; >>>>> >>>>> >>>>> u = foreach g generate myUDF($2) as triplets; >>>>> describe u; >>>>> dump u; >>>>> >>>>> Do you see any reason there should be 1 reducer at any stage? How do I >>>>> debug this? Where are the generated classes and plan? >>>>> >>>>> -Ayon >>>>> See My Photos on Flickr >>>>> Also check out my Blog for answers to commonly asked questions. >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>> >>>
