org.apache.hadoop.hbase.coprocessor

Interface RegionServerObserver

All Known Implementing Classes:

AccessController, VisibilityReplication

@InterfaceAudience.LimitedPrivate(value="Coprocesssor")
 @InterfaceStability.Evolving
public interface RegionServerObserver

Defines coprocessor hooks for interacting with operations on the HRegionServer process. Since most implementations will be interested in only a subset of hooks, this class uses 'default' functions to avoid having to add unnecessary overrides. When the functions are non-empty, it's simply to satisfy the compiler by returning value of expected (non-void) type. It is done in a way that these default definitions act as no-op. So our suggestion to implementation would be to not call these 'default' methods from overrides.

Exception Handling

For all functions, exception handling is done as follows:

• Exceptions of type IOException are reported back to client.
• For any other kind of exception:
  • If the configuration CoprocessorHost.ABORT_ON_ERROR_KEY is set to true, then the server aborts.
  • Otherwise, coprocessor is removed from the server and DoNotRetryIOException is returned to the client.

Method Summary

Modifier and Type	Method and Description
default void	postClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx) This will be called after clearing compaction queues
default ReplicationEndpoint	postCreateReplicationEndPoint(ObserverContext<RegionServerCoprocessorEnvironment> ctx, ReplicationEndpoint endpoint) This will be called after the replication endpoint is instantiated.
default void	postReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx) Deprecated. As of release 2.0.0 with out any replacement. This is maintained for internal usage by AccessController. Do not use these hooks in custom co-processors.
default void	postRollWALWriterRequest(ObserverContext<RegionServerCoprocessorEnvironment> ctx) This will be called after executing user request to roll a region server WAL.
default void	preClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx) This will be called before clearing compaction queues
default void	preReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx) Deprecated. As of release 2.0.0 with out any replacement. This is maintained for internal usage by AccessController. Do not use these hooks in custom co-processors.
default void	preRollWALWriterRequest(ObserverContext<RegionServerCoprocessorEnvironment> ctx) This will be called before executing user request to roll a region server WAL.
default void	preStopRegionServer(ObserverContext<RegionServerCoprocessorEnvironment> ctx) Called before stopping region server.

Method Detail

preStopRegionServer

default void preStopRegionServer(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                          throws IOException

Called before stopping region server.

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

preRollWALWriterRequest

default void preRollWALWriterRequest(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                              throws IOException

This will be called before executing user request to roll a region server WAL.

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

postRollWALWriterRequest

default void postRollWALWriterRequest(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                               throws IOException

This will be called after executing user request to roll a region server WAL.

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

postCreateReplicationEndPoint

default ReplicationEndpoint postCreateReplicationEndPoint(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                                                          ReplicationEndpoint endpoint)

This will be called after the replication endpoint is instantiated.

Parameters:

ctx - the environment to interact with the framework and region server.

endpoint - - the base endpoint for replication

Returns:

the endpoint to use during replication.

preReplicateLogEntries

@Deprecated
default void preReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                                         throws IOException

Deprecated. As of release 2.0.0 with out any replacement. This is maintained for internal usage by AccessController. Do not use these hooks in custom co-processors.

This will be called before executing replication request to shipping log entries.

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

postReplicateLogEntries

@Deprecated
default void postReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                                          throws IOException

Deprecated. As of release 2.0.0 with out any replacement. This is maintained for internal usage by AccessController. Do not use these hooks in custom co-processors.

This will be called after executing replication request to shipping log entries.

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

preClearCompactionQueues

default void preClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                               throws IOException

This will be called before clearing compaction queues

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException

postClearCompactionQueues

default void postClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
                                throws IOException

This will be called after clearing compaction queues

Parameters:

ctx - the environment to interact with the framework and region server.

Throws:

IOException