[HBASE-19301] Provide way for CPs to create short circuited connection with custom configurations

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0-beta-1, 2.0.0
• Component/s: Coprocessors
• Hadoop Flags: Reviewed

Release Note

Provided a way for the CP users to create a short circuitable connection with custom configs.

createConnection(Configuration) is added to MasterCoprocessorEnvironment, RegionServerCoprocessorEnvironment and RegionCoprocessorEnvironment.

The getConnection() method already available in these Env interfaces returns the cluster connection used by the server (which the server also uses) where as this new method will create a new connection on request. The difference from connection created using ConnectionFactory APIs is that this connection can short circuit the calls to same server avoiding the RPC paths. The connection will NOT be cached/maintained by server. That should be done the CPs.

Be careful creating Connections out of a Coprocessor. See the javadoc on these createConnection and getConnection.

• Assignee: Anoop Sam John
• Reporter: Anoop Sam John
• Created: 19/Nov/17 11:10
• Updated: 17/Jun/22 05:24
• Resolved: 07/Dec/17 14:44

Description

Over in HBASE-18359 we have discussions for this.
Right now HBase provide getConnection() in RegionCPEnv, MasterCPEnv etc. But this returns a pre created connection (per server). This uses the configs at hbase-site.xml at that server.
Phoenix needs creating connection in CP with some custom configs. Having this custom changes in hbase-site.xml is harmful as that will affect all connections been created at that server.
This issue is for providing an overloaded getConnection(Configuration) API

Issue Links

• is related to: HBASE-19316 Direct invocation Client-Server short-circuit without having to pass through the eye of a protobuf stub
• relates to: HBASE-19463 Make CPEnv#getConnection return a facade that throws Unsupported if CP calls #close
• links to: Review Board (master)