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stack commented on HBASE-7342: ------------------------------ [~ram_krish] No problem boss. Thats interesting that you saw this below. Would be good to know what you fellas decided? Good on you. > Split operation without split key incorrectly finds the middle key in > off-by-one error > -------------------------------------------------------------------------------------- > > Key: HBASE-7342 > URL: https://issues.apache.org/jira/browse/HBASE-7342 > Project: HBase > Issue Type: Bug > Components: HFile, io > Affects Versions: 0.94.1, 0.94.2, 0.94.3, 0.96.0 > Reporter: Aleksandr Shulman > Assignee: Aleksandr Shulman > Priority: Minor > Fix For: 0.96.0, 0.94.4 > > Attachments: HBASE-7342-v1.patch, HBASE-7342-v2.patch > > > I took a deeper look into issues I was having using region splitting when > specifying a region (but not a key for splitting). > The midkey calculation is off by one and when there are 2 rows, will pick the > 0th one. This causes the firstkey to be the same as midkey and the split will > fail. Removing the -1 causes it work correctly, as per the test I've added. > Looking into the code here is what goes on: > 1. Split takes the largest storefile > 2. It puts all the keys into a 2-dimensional array called blockKeys[][]. Key > i resides as blockKeys[i] > 3. Getting the middle root-level index should yield the key in the middle of > the storefile > 4. In step 3, we see that there is a possible erroneous (-1) to adjust for > the 0-offset indexing. > 5. In a result with where there are only 2 blockKeys, this yields the 0th > block key. > 6. Unfortunately, this is the same block key that 'firstKey' will be. > 7. This yields the result in HStore.java:1873 ("cannot split because midkey > is the same as first or last row") > 8. Removing the -1 solves the problem (in this case). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira