[CRUNCH-614] HFileUtils.writeToHFilesForIncrementalLoad slowed dramatically by copying KeyValue byte array

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.0, 0.10.0, 0.11.0, 0.12.0, 0.13.0, 0.14.0
• Fix Version/s: 0.15.0
• Assignee: Josh Wills
• Reporter: Ben Roling
• Created: 27/Jul/16 16:27
• Updated: 26/Feb/17 18:33
• Resolved: 30/Jul/16 00:47

Description

I raised this issue on the mailing list:
http://mail-archives.apache.org/mod_mbox/crunch-user/201607.mbox/%3CCANBdsh01qaQRCNdQdtqytP%2BWAhT_NVGHyQAdDS8H%2BPPMfi9bkw%40mail.gmail.com%3E

HFileUtils was changed in such a way that it makes a copy of the KeyValue byte array in the compare() method of the KeyValueComparator. The change was made with the following commit:

https://github.com/apache/crunch/commit/a959ee6c7fc400d1f455b0742641c54de1dec0bf#diff-bc76ce0b41704c9c4efbfa1aab53588d

The change causes HFileUtils.writeToHFilesForIncrementalLoad to be dramatically slower in at least some cases.

The code changed from using the KeyValue(byte[], int, int) constructor to using KeyValue.create(). KeyValue.create() does a byte array copy. The fix is likely as simple as changing the code back to using the KeyValue constructor.

I will do some testing an attach a PR for the fix.