[HBASE-8496] Implement tags and the internals of how a tag should look like

• Type: New Feature
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.98.0, 0.95.2
• Fix Version/s: 0.98.0
• Hadoop Flags: Incompatible change, Reviewed

Release Note

Tags are additional metadata to be added with the KVs.
To enable the tags to be persisted in the HFiles, V3 version of HFile should be used.
<property>
      <name>hfile.format.version</name>
      <value>3</value>
  </property>
The tags has the below format
<2 byte tag length><1 byte type code><tag>
where <type> is the type of the tag, <tag> is a byte[] that has the tag data.
To add Tags using Puts
Put.add(byte[] family, byte [] qualifier, byte [] value, Tag[] tag)
Put.add(byte[] family, byte[] qualifier, long ts, byte[] value, Tag[] tag)
Can be used.
Note that even after changing the version to V3, the no-tag case will also be working fine as in V2 format.

• Assignee: ramkrishna.s.vasudevan
• Reporter: ramkrishna.s.vasudevan
• Created: 06/May/13 03:45
• Updated: 20/Nov/15 11:55
• Resolved: 21/Sep/13 18:21

Description

The intent of this JIRA comes from HBASE-7897.
This would help us to decide on the structure and format of how the tags should look like.

Issue Links

• is related to: HBASE-7897 Add support for tags to Cell Interface
• is required by: HBASE-6222 Add per-KeyValue Security
• is required by: HBASE-7544 Transparent table/CF encryption
• relates to: HBASE-9816 Address review comments in HBASE-8496
• relates to: HBASE-9801 Change the default HFile version to V3

Sub-Tasks

• Support Dictionary based Tag compression in HFiles: Closed
• Add client side support for Tags: Resolved
• Support Tags in ImportTSV tool: Open
• Optimization in HFile V3 when no tags are present in a file: Closed
• RPC side changes to have a different codec for server to client communication: Closed
• Add Tag dictionary in WAL compression: Closed
• HFileContext should adopt Builder pattern: Closed
• HStore should use HFileContext for holding the state therein rather than duplicating it: Open
• HFileContext defaults can lead to inconsistency with expectations of HFile block header sizing between readers and writers: Resolved