[HBASE-13939] Make HFileReaderImpl.getFirstKeyInBlock() to return a Cell

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Hadoop Flags: Reviewed
• Assignee: ramkrishna.s.vasudevan
• Reporter: ramkrishna.s.vasudevan
• Created: 19/Jun/15 05:55
• Updated: 30/Jun/15 10:53
• Resolved: 30/Jun/15 10:53

Description

The getFirstKeyInBlock() in HFileReaderImpl is returning a BB. It is getting used in seekBefore cases. Because we return a BB we create a KeyOnlyKV once for comparison

      if (reader.getComparator()
          .compareKeyIgnoresMvcc(
              new KeyValue.KeyOnlyKeyValue(firstKey.array(), firstKey.arrayOffset(),
                  firstKey.limit()), key) >= 0) {
        long previousBlockOffset = seekToBlock.getPrevBlockOffset();
        // The key we are interested in
        if (previousBlockOffset == -1) {
          // we have a 'problem', the key we want is the first of the file.
          return false;
        }
........

And if the compare fails we again create another KeyOnlyKv

      Cell firstKeyInCurrentBlock = new KeyValue.KeyOnlyKeyValue(Bytes.getBytes(firstKey));
      loadBlockAndSeekToKey(seekToBlock, firstKeyInCurrentBlock, true, key, true);

So one object will be enough and that can be returned by getFirstKeyInBlock. Also will be useful when we go with Buffered backed server cell to change in one place.

Issue Links

• relates to: HBASE-13945 Prefix_Tree seekBefore() does not work correctly