[HBASE-21860] WALFactory should switch to default provider if multiwal provider is defined for meta wal (Per suggestions on HBASE-21843)

• Type: Improvement
• Status: Patch Available
• Priority: Critical
• Resolution: Unresolved
• Component/s: wal
• Assignee: Wellington Chevreuil
• Reporter: Wellington Chevreuil
• Created: 08/Feb/19 12:49
• Updated: 12/Feb/19 17:00

Description

Following discussions on HBASE-21843, one of the suggestion was to make wal provider for meta wal switch to default provider if multi wal is defined as the target provider. Quoting busbey:

I don't think it's a good idea to revert HBASE-20856. the principles of that issue are still sound.

We already have logic somewhere for the AsyncDFS based WAL that falls back to the default if something goes wrong with the needed HDFS hooks. Can we do something similar for the region grouping provider and make the check something like "did you ask for a provider for meta"?

Am uploading a patch that switches to default whenever WALFactory finds multiwal provider is defined for meta wal (either explicitly by defining "hbase.wal.meta_provider", or indirectly, by loading what is in "hbase.wal.provider")