[HBASE-2794] Utilize ROWCOL bloom filter if multiple columns within same family are requested in a Get

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.92.0
• Component/s: Performance
• Release Note: Resolving (the patch has been committed).
• Assignee: Mikhail Gryzykhin
• Reporter: Kannan Muthukkaruppan
• Created: 26/Jun/10 07:46
• Updated: 20/Nov/15 12:41
• Resolved: 30/Sep/11 22:33

Description

Noticed the following snippet in StoreFile.java:Scanner:shouldSeek():

        switch(bloomFilterType) {
          case ROW:
            key = row;
            break;
          case ROWCOL:
            if (columns.size() == 1) {
              byte[] col = columns.first();
              key = Bytes.add(row, col);
              break;
            }
            //$FALL-THROUGH$
          default:
            return true;
        }

If columns.size > 1, then we currently don't take advantage of the bloom filter. We should optimize this to check bloom for each of columns and if none of the columns are present in the bloom avoid opening the file.