[HBASE-5604] M/R tool to replay WAL files

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.94.0, 0.95.0
• Hadoop Flags: Reviewed

Release Note

Tool to replay WAL files using a M/R job.

The WAL can be replayed for a set of tables or all tables, and a timerange can be provided (in milliseconds).
The WAL is filtered to this set of tables, the output can optionally be mapped to another set of tables.

WAL replay can also generate HFiles for later bulk importing, in that case the WAL is replayed for a single table only.

• Assignee: Lars Hofhansl
• Reporter: Lars Hofhansl
• Created: 20/Mar/12 17:14
• Updated: 26/Feb/13 08:12
• Resolved: 12/Apr/12 22:33

Description

Just an idea I had. Might be useful for restore of a backup using the HLogs.
This could an M/R (with a mapper per HLog file).

The tool would get a timerange and a (set of) table(s). We'd pick the right HLogs based on time before the M/R job is started and then have a mapper per HLog file.
The mapper would then go through the HLog, filter all WALEdits that didn't fit into the time range or are not any of the tables and then uses HFileOutputFormat to generate HFiles.
Would need to indicate the splits we want, probably from a live table.

Issue Links

• duplicates: HBASE-5774 Add documentation for WALPlayer to HBase reference guide.
• is related to: HBASE-3752 Tool to replay moved-aside WAL logs

Sub-Tasks

• Add documentation for WALPlayer to HBase reference guide.: Closed