Package org.apache.hadoop.hbase.coprocessor

Interface RegionServerObserver

All Known Implementing Classes:

AccessController, VisibilityReplication

@LimitedPrivate("Coprocesssor")
@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	Description
default void	postClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	This will be called after clearing compaction queues
default void	postClearRegionBlockCache(ObserverContext<RegionServerCoprocessorEnvironment> ctx, CacheEvictionStats stats)	Called after clearing the block caches for one or more regions
default ReplicationEndpoint	postCreateReplicationEndPoint(ObserverContext<RegionServerCoprocessorEnvironment> ctx, ReplicationEndpoint endpoint)	This will be called after the replication endpoint is instantiated.
default void	postExecuteProcedures(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	This will be called after executing procedures
default void	postReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	Deprecated. As of release 2.0.0 with out any replacement.
default void	postReplicationSinkBatchMutate(ObserverContext<RegionServerCoprocessorEnvironment> ctx, org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry walEntry, Mutation mutation)	This will be called after replication sink mutations are executed on the sink table as part of batch call.
default void	postRollWALWriterRequest(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	This will be called after executing user request to roll a region server WAL.
default void	postUpdateRegionServerConfiguration(ObserverContext<RegionServerCoprocessorEnvironment> ctx, org.apache.hadoop.conf.Configuration postReloadConf)	Called after reloading the RegionServer's Configuration from disk
default void	preClearCompactionQueues(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	This will be called before clearing compaction queues
default void	preClearRegionBlockCache(ObserverContext<RegionServerCoprocessorEnvironment> ctx)
default void	preExecuteProcedures(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	This will be called before executing procedures
default void	preReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx)	Deprecated. As of release 2.0.0 with out any replacement.
default void	preReplicationSinkBatchMutate(ObserverContext<RegionServerCoprocessorEnvironment> ctx, org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry walEntry, Mutation mutation)	This will be called before replication sink mutations are executed on the sink table as part of batch call.
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.
default void	preUpdateRegionServerConfiguration(ObserverContext<RegionServerCoprocessorEnvironment> ctx, org.apache.hadoop.conf.Configuration preReloadConf)	Called before reloading the RegionServer's Configuration from disk

Method Details

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

preExecuteProcedures

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

This will be called before executing procedures

Parameters:

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

Throws:

IOException

postExecuteProcedures

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

This will be called after executing procedures

Parameters:

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

Throws:

IOException

preReplicationSinkBatchMutate

default void preReplicationSinkBatchMutate(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
 org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry walEntry,
 Mutation mutation)
                                    throws IOException

This will be called before replication sink mutations are executed on the sink table as part of batch call.

Parameters:

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

walEntry - wal entry from which mutation is formed.

mutation - mutation to be applied at sink cluster.

Throws:

IOException - if something goes wrong.

postReplicationSinkBatchMutate

default void postReplicationSinkBatchMutate(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
 org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry walEntry,
 Mutation mutation)
                                     throws IOException

This will be called after replication sink mutations are executed on the sink table as part of batch call.

Parameters:

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

walEntry - wal entry from which mutation is formed.

mutation - mutation to be applied at sink cluster.

Throws:

IOException - if something goes wrong.

preClearRegionBlockCache

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

Throws:

IOException

postClearRegionBlockCache

default void postClearRegionBlockCache(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
 CacheEvictionStats stats)
                                throws IOException

Called after clearing the block caches for one or more regions

Parameters:

ctx - the coprocessor instance's environment

stats - statistics about the cache evictions that happened

Throws:

IOException - if you need to signal an IO error

preUpdateRegionServerConfiguration

default void preUpdateRegionServerConfiguration(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
 org.apache.hadoop.conf.Configuration preReloadConf)
                                         throws IOException

Called before reloading the RegionServer's Configuration from disk

Parameters:

ctx - the coprocessor instance's environment

preReloadConf - the Configuration in use prior to reload

Throws:

IOException - if you need to signal an IO error

postUpdateRegionServerConfiguration

default void postUpdateRegionServerConfiguration(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
 org.apache.hadoop.conf.Configuration postReloadConf)
                                          throws IOException

Called after reloading the RegionServer's Configuration from disk

Parameters:

ctx - the coprocessor instance's environment

postReloadConf - the Configuration that was loaded

Throws:

IOException - if you need to signal an IO error