[HBASE-9118] Optimization in HFile V3 when no tags are present in a file

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.98.0, 0.95.2
• Fix Version/s: 0.98.0
• Assignee: Anoop Sam John
• Reporter: Anoop Sam John
• Created: 02/Aug/13 19:08
• Updated: 20/Nov/15 11:53
• Resolved: 26/Sep/13 11:24

Description

Now with V3 we will write tags length (short) along with every KV after value bytes. When no tags at all present it will be wasting 2 bytes for every KV. We can avoid this. During flush let the tags length be written. In fileInfo we can add info like max tags length. During compaction if all the files undergoing the compaction having a 0 max tags length, we can avoid writing 2 bytes (0) along with every KV..

Note : Similar optimization available with mvcc