org.apache.hadoop.hbase.coprocessor

Interface RegionServerObserver

All Superinterfaces:

Coprocessor

All Known Implementing Classes:

AccessController, VisibilityController.VisibilityReplication

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

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.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.Coprocessor

Coprocessor.State

Field Summary

Fields inherited from interface org.apache.hadoop.hbase.Coprocessor

PRIORITY_HIGHEST, PRIORITY_LOWEST, PRIORITY_SYSTEM, PRIORITY_USER, VERSION

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	postMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB, Region mergedRegion) called after the regions merge.
default void	postMergeCommit(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB, Region mergedRegion) This will be called after PONR step as part of regions merge transaction.
default void	postReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx, List<org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry> entries, CellScanner cells) This will be called after executing replication request to shipping log entries.
default void	postRollBackMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB) This will be called after the roll back of the regions merge.
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	preMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB) Called before the regions merge.
default void	preMergeCommit(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB, List<Mutation> metaEntries) This will be called before PONR step as part of regions merge transaction.
default void	preReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx, List<org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry> entries, CellScanner cells) This will be called before executing replication request to shipping log entries.
default void	preRollBackMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx, Region regionA, Region regionB) This will be called before the roll back of the regions merge.
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.

Methods inherited from interface org.apache.hadoop.hbase.Coprocessor

start, stop

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

preMerge

default void preMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                      Region regionA,
                      Region regionB)
               throws IOException

Called before the regions merge. Call ObserverContext.bypass() to skip the merge.

Parameters:

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

regionA - region being merged.

regionB - region being merged.

Throws:

IOException

postMerge

default void postMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                       Region regionA,
                       Region regionB,
                       Region mergedRegion)
                throws IOException

called after the regions merge.

Parameters:

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

regionA - region being merged.

regionB - region being merged.

Throws:

IOException

preMergeCommit

default void preMergeCommit(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                            Region regionA,
                            Region regionB,
                            @MetaMutationAnnotation
                            List<Mutation> metaEntries)
                     throws IOException

This will be called before PONR step as part of regions merge transaction. Calling ObserverContext.bypass() rollback the merge

Parameters:

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

regionA - region being merged.

regionB - region being merged.

metaEntries - mutations to execute on hbase:meta atomically with regions merge updates. Any puts or deletes to execute on hbase:meta can be added to the mutations.

Throws:

IOException

postMergeCommit

default void postMergeCommit(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                             Region regionA,
                             Region regionB,
                             Region mergedRegion)
                      throws IOException

This will be called after PONR step as part of regions merge transaction.

Parameters:

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

regionA - region being merged.

regionB - region being merged.

Throws:

IOException

preRollBackMerge

default void preRollBackMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                              Region regionA,
                              Region regionB)
                       throws IOException

This will be called before the roll back of the regions merge.

Parameters:

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

regionA - region being merged.

regionB - region being merged.

Throws:

IOException

postRollBackMerge

default void postRollBackMerge(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                               Region regionA,
                               Region regionB)
                        throws IOException

This will be called after the roll back of the regions merge.

Parameters:

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

regionA - region being merged.

regionB - region being merged.

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

default void preReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                                    List<org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry> entries,
                                    CellScanner cells)
                             throws IOException

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

Parameters:

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

entries - list of WALEntries to replicate

cells - Cells that the WALEntries refer to (if cells is non-null)

Throws:

IOException

postReplicateLogEntries

default void postReplicateLogEntries(ObserverContext<RegionServerCoprocessorEnvironment> ctx,
                                     List<org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.WALEntry> entries,
                                     CellScanner cells)
                              throws IOException

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

Parameters:

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

entries - list of WALEntries to replicate

cells - Cells that the WALEntries refer to (if cells is non-null)

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