[HBASE-7952] Remove update() and Improve ExplicitColumnTracker performance.

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.94.1, 0.94.5
• Fix Version/s: 0.98.0, 0.95.0
• Component/s: regionserver
• Assignee: Raymond Liu
• Reporter: Raymond Liu
• Created: 27/Feb/13 07:54
• Updated: 23/Sep/13 18:31
• Resolved: 13/Mar/13 06:05

Description

In ColumnTracker.java, the update() method is not used by anyone now. And no one will call checkColumn for different HFiles with update() in between files to re-walk through the target columns. All columns will be feed to checkColumn() in order.

So, within ExplicitColumnTracker, the target columns can be optimized to not dynamic maintain a changing list of columns yet to match. Instead, just move index through it is enough.

with this optimization to save the time for avoid reconstruct a columns array upon each row, the checkColumn method's performance could be improved by 10-20%.