Thanks for the reply Robert, However I believe the main design issue is: If there is a rack ( listed in rackToBlock hashMap) that contains all the blocks (stored in blockToNode hashMap), regardless of the order, the split operation terminates after the rack gets processed, That means remaining racks ( listed in rackToBlock hashMap) will not get processed . For more details look at file CombineFileInputFormat.JAVA, method getMoreSplits(), while loop starting at line 344.
Best Regards Amir Sanjar Linux System Management Architect and Lead IBM Senior Software Engineer Phone# 512-286-8393 Fax# 512-838-8858 From: Robert Evans <ev...@yahoo-inc.com> To: "common-dev@hadoop.apache.org" <common-dev@hadoop.apache.org> Date: 03/22/2012 11:57 AM Subject: Re: Question about Hadoop-8192 and rackToBlocks ordering If it really is the ordering of the hash map I would say no it should not, and the code should be updated. If ordering matters we need to use a map that guarantees a given order, and hash map is not one of them. --Bobby Evans On 3/22/12 7:24 AM, "Kumar Ravi" <gokumarr...@gmail.com> wrote: Hello, We have been looking at IBM JDK junit failures on Hadoop-1.0.1 independently and have ran into the same failures as reported in this JIRA. I have a question based upon what I have observed below. We started debugging the problems in the testcase - org.apache.hadoop.mapred.lib.TestCombineFileInputFormat The testcase fails because the number of splits returned back from CombineFileInputFormat.getSplits() is 1 when using IBM JDK whereas the expected return value is 2. So far, we have found the reason for this difference in number of splits is because the order in which elements in the rackToBlocks hashmap get created is in the reverse order that Sun JDK creates. The question I have at this point is -- Should there be a strict dependency in the order in which the rackToBlocks hashmap gets populated, to determine the number of splits that get should get created in a hadoop cluster? Is this Working as designed? Regards, Kumar
