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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.hadoop.hbase.coprocessor;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CompareOperator;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.client.Append;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Durability;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Increment;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.ByteArrayComparable;
import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
import org.apache.hadoop.hbase.io.Reference;
import org.apache.hadoop.hbase.io.hfile.CacheConfig;
import org.apache.hadoop.hbase.regionserver.FlushLifeCycleTracker;
import org.apache.hadoop.hbase.regionserver.InternalScanner;
import org.apache.hadoop.hbase.regionserver.MiniBatchOperationInProgress;
import org.apache.hadoop.hbase.regionserver.OperationStatus;
import org.apache.hadoop.hbase.regionserver.Region;
import org.apache.hadoop.hbase.regionserver.Region.Operation;
import org.apache.hadoop.hbase.regionserver.RegionScanner;
import org.apache.hadoop.hbase.regionserver.ScanOptions;
import org.apache.hadoop.hbase.regionserver.ScanType;
import org.apache.hadoop.hbase.regionserver.Store;
import org.apache.hadoop.hbase.regionserver.StoreFile;
import org.apache.hadoop.hbase.regionserver.StoreFileReader;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionLifeCycleTracker;
import org.apache.hadoop.hbase.regionserver.compactions.CompactionRequest;
import org.apache.hadoop.hbase.regionserver.querymatcher.DeleteTracker;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.hadoop.hbase.wal.WALEdit;
import org.apache.hadoop.hbase.wal.WALKey;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.yetus.audience.InterfaceStability;
/**
* Coprocessors implement this interface to observe and mediate client actions on the region.
*
* 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 {@link IOException} are reported back to client.
* - For any other kind of exception:
*
* - If the configuration {@link CoprocessorHost#ABORT_ON_ERROR_KEY} is set to true, then the
* server aborts.
* - Otherwise, coprocessor is removed from the server and
* {@link org.apache.hadoop.hbase.DoNotRetryIOException} is returned to the client.
*
*
*
*
*
For Split Related Hooks
* In hbase2/AMv2, master runs splits, so the split related hooks are moved to
* {@link MasterObserver}.
*
*
Increment Column Value
* We do not call this hook anymore.
*/
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
@InterfaceStability.Evolving
// TODO as method signatures need to break, update to
// ObserverContext
// so we can use additional environment state that isn't exposed to coprocessors.
public interface RegionObserver {
/** Mutation type for postMutationBeforeWAL hook */
enum MutationType {
APPEND, INCREMENT
}
/**
* Called before the region is reported as open to the master.
* @param c the environment provided by the region server
*/
default void preOpen(ObserverContext c) throws IOException {}
/**
* Called after the region is reported as open to the master.
* @param c the environment provided by the region server
*/
default void postOpen(ObserverContext c) {}
/**
* Called before the memstore is flushed to disk.
* @param c the environment provided by the region server
* @param tracker tracker used to track the life cycle of a flush
*/
default void preFlush(final ObserverContext c,
FlushLifeCycleTracker tracker) throws IOException {}
/**
* Called before we open store scanner for flush. You can use the {@code options} to change max
* versions and TTL for the scanner being opened.
* @param c the environment provided by the region server
* @param store the store where flush is being requested
* @param options used to change max versions and TTL for the scanner being opened
*/
default void preFlushScannerOpen(ObserverContext c, Store store,
ScanOptions options,FlushLifeCycleTracker tracker) throws IOException {}
/**
* Called before a Store's memstore is flushed to disk.
* @param c the environment provided by the region server
* @param store the store where flush is being requested
* @param scanner the scanner over existing data used in the memstore
* @param tracker tracker used to track the life cycle of a flush
* @return the scanner to use during flush. Should not be {@code null} unless the implementation
* is writing new store files on its own.
*/
default InternalScanner preFlush(ObserverContext c, Store store,
InternalScanner scanner, FlushLifeCycleTracker tracker) throws IOException {
return scanner;
}
/**
* Called after the memstore is flushed to disk.
* @param c the environment provided by the region server
* @param tracker tracker used to track the life cycle of a flush
* @throws IOException if an error occurred on the coprocessor
*/
default void postFlush(ObserverContext c,
FlushLifeCycleTracker tracker) throws IOException {}
/**
* Called after a Store's memstore is flushed to disk.
* @param c the environment provided by the region server
* @param store the store being flushed
* @param resultFile the new store file written out during compaction
* @param tracker tracker used to track the life cycle of a flush
*/
default void postFlush(ObserverContext c, Store store,
StoreFile resultFile, FlushLifeCycleTracker tracker) throws IOException {}
/**
* Called before in memory compaction started.
* @param c the environment provided by the region server
* @param store the store where in memory compaction is being requested
*/
default void preMemStoreCompaction(ObserverContext c, Store store)
throws IOException {}
/**
* Called before we open store scanner for in memory compaction. You can use the {@code options}
* to change max versions and TTL for the scanner being opened. Notice that this method will only
* be called when you use {@code eager} mode. For {@code basic} mode we will not drop any cells
* thus we do not open a store scanner.
* @param c the environment provided by the region server
* @param store the store where in memory compaction is being requested
* @param options used to change max versions and TTL for the scanner being opened
*/
default void preMemStoreCompactionCompactScannerOpen(
ObserverContext c, Store store, ScanOptions options)
throws IOException {}
/**
* Called before we do in memory compaction. Notice that this method will only be called when you
* use {@code eager} mode. For {@code basic} mode we will not drop any cells thus there is no
* {@link InternalScanner}.
* @param c the environment provided by the region server
* @param store the store where in memory compaction is being executed
* @param scanner the scanner over existing data used in the memstore segments being compact
* @return the scanner to use during in memory compaction. Must be non-null.
*/
default InternalScanner preMemStoreCompactionCompact(
ObserverContext c, Store store, InternalScanner scanner)
throws IOException {
return scanner;
}
/**
* Called after the in memory compaction is finished.
* @param c the environment provided by the region server
* @param store the store where in memory compaction is being executed
*/
default void postMemStoreCompaction(ObserverContext c, Store store)
throws IOException {}
/**
* Called prior to selecting the {@link StoreFile StoreFiles} to compact from the list of
* available candidates. To alter the files used for compaction, you may mutate the passed in list
* of candidates. If you remove all the candidates then the compaction will be canceled.
* Supports Coprocessor 'bypass' -- 'bypass' is how this method indicates that it changed
* the passed in candidates.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
* @param c the environment provided by the region server
* @param store the store where compaction is being requested
* @param candidates the store files currently available for compaction
* @param tracker tracker used to track the life cycle of a compaction
*/
default void preCompactSelection(ObserverContext c, Store store,
List candidates, CompactionLifeCycleTracker tracker)
throws IOException {}
/**
* Called after the {@link StoreFile}s to compact have been selected from the available
* candidates.
* @param c the environment provided by the region server
* @param store the store being compacted
* @param selected the store files selected to compact
* @param tracker tracker used to track the life cycle of a compaction
* @param request the requested compaction
*/
default void postCompactSelection(ObserverContext c, Store store,
List selected, CompactionLifeCycleTracker tracker,
CompactionRequest request) {}
/**
* Called before we open store scanner for compaction. You can use the {@code options} to change max
* versions and TTL for the scanner being opened.
* @param c the environment provided by the region server
* @param store the store being compacted
* @param scanType type of Scan
* @param options used to change max versions and TTL for the scanner being opened
* @param tracker tracker used to track the life cycle of a compaction
* @param request the requested compaction
*/
default void preCompactScannerOpen(ObserverContext c, Store store,
ScanType scanType, ScanOptions options, CompactionLifeCycleTracker tracker,
CompactionRequest request) throws IOException {}
/**
* Called prior to writing the {@link StoreFile}s selected for compaction into a new
* {@code StoreFile}.
*
* To override or modify the compaction process, implementing classes can wrap the provided
* {@link InternalScanner} with a custom implementation that is returned from this method. The
* custom scanner can then inspect {@link org.apache.hadoop.hbase.Cell}s from the wrapped scanner,
* applying its own policy to what gets written.
* @param c the environment provided by the region server
* @param store the store being compacted
* @param scanner the scanner over existing data used in the store file rewriting
* @param scanType type of Scan
* @param tracker tracker used to track the life cycle of a compaction
* @param request the requested compaction
* @return the scanner to use during compaction. Should not be {@code null} unless the
* implementation is writing new store files on its own.
*/
default InternalScanner preCompact(ObserverContext c, Store store,
InternalScanner scanner, ScanType scanType, CompactionLifeCycleTracker tracker,
CompactionRequest request) throws IOException {
return scanner;
}
/**
* Called after compaction has completed and the new store file has been moved in to place.
* @param c the environment provided by the region server
* @param store the store being compacted
* @param resultFile the new store file written out during compaction
* @param tracker used to track the life cycle of a compaction
* @param request the requested compaction
*/
default void postCompact(ObserverContext c, Store store,
StoreFile resultFile, CompactionLifeCycleTracker tracker, CompactionRequest request)
throws IOException {}
/**
* Called before the region is reported as closed to the master.
* @param c the environment provided by the region server
* @param abortRequested true if the region server is aborting
*/
default void preClose(ObserverContext c, boolean abortRequested)
throws IOException {}
/**
* Called after the region is reported as closed to the master.
* @param c the environment provided by the region server
* @param abortRequested true if the region server is aborting
*/
default void postClose(ObserverContext c, boolean abortRequested) {}
/**
* Called before the client performs a Get
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
* @param c the environment provided by the region server
* @param get the Get request
* @param result The result to return to the client if default processing
* is bypassed. Can be modified. Will not be used if default processing
* is not bypassed.
*/
default void preGetOp(ObserverContext c, Get get, List| result)
throws IOException {}
/**
* Called after the client performs a Get
*
* Note: Do not retain references to any Cells in 'result' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param get the Get request
* @param result the result to return to the client, modify as necessary
*/
default void postGetOp(ObserverContext c, Get get,
List| result) throws IOException {}
/**
* Called before the client tests for existence using a Get.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
* @param c the environment provided by the region server
* @param get the Get request
* @param exists the result returned by the region server
* @return the value to return to the client if bypassing default processing
*/
default boolean preExists(ObserverContext c, Get get,
boolean exists) throws IOException {
return exists;
}
/**
* Called after the client tests for existence using a Get.
* @param c the environment provided by the region server
* @param get the Get request
* @param exists the result returned by the region server
* @return the result to return to the client
*/
default boolean postExists(ObserverContext c, Get get,
boolean exists) throws IOException {
return exists;
}
/**
* Called before the client stores a value.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'put' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param put The Put object
* @param edit The WALEdit object that will be written to the wal
* @param durability Persistence guarantee for this Put
*/
default void prePut(ObserverContext c, Put put, WALEdit edit,
Durability durability) throws IOException {}
/**
* Called after the client stores a value.
*
* Note: Do not retain references to any Cells in 'put' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param put The Put object
* @param edit The WALEdit object for the wal
* @param durability Persistence guarantee for this Put
*/
default void postPut(ObserverContext c, Put put, WALEdit edit,
Durability durability) throws IOException {}
/**
* Called before the client deletes a value.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'delete' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param delete The Delete object
* @param edit The WALEdit object for the wal
* @param durability Persistence guarantee for this Delete
*/
default void preDelete(ObserverContext c, Delete delete,
WALEdit edit, Durability durability) throws IOException {}
/**
* Called before the server updates the timestamp for version delete with latest timestamp.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
* @param c the environment provided by the region server
* @param mutation - the parent mutation associated with this delete cell
* @param cell - The deleteColumn with latest version cell
* @param byteNow - timestamp bytes
* @param get - the get formed using the current cell's row. Note that the get does not specify
* the family and qualifier
* @deprecated Since hbase-2.0.0. No replacement. To be removed in hbase-3.0.0 and replaced
* with something that doesn't expose IntefaceAudience.Private classes.
*/
@Deprecated
default void prePrepareTimeStampForDeleteVersion(ObserverContext c,
Mutation mutation, Cell cell, byte[] byteNow, Get get) throws IOException {}
/**
* Called after the client deletes a value.
*
* Note: Do not retain references to any Cells in 'delete' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param delete The Delete object
* @param edit The WALEdit object for the wal
* @param durability Persistence guarantee for this Delete
*/
default void postDelete(ObserverContext c, Delete delete,
WALEdit edit, Durability durability) throws IOException {}
/**
* This will be called for every batch mutation operation happening at the server. This will be
* called after acquiring the locks on the mutating rows and after applying the proper timestamp
* for each Mutation at the server. The batch may contain Put/Delete. By setting OperationStatus
* of Mutations ({@link MiniBatchOperationInProgress#setOperationStatus(int, OperationStatus)}),
* {@link RegionObserver} can make Region to skip these Mutations.
*
* Note: Do not retain references to any Cells in Mutations beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param miniBatchOp batch of Mutations getting applied to region.
*/
default void preBatchMutate(ObserverContext c,
MiniBatchOperationInProgress miniBatchOp) throws IOException {}
/**
* This will be called after applying a batch of Mutations on a region. The Mutations are added to
* memstore and WAL. The difference of this one with
* {@link #postPut(ObserverContext, Put, WALEdit, Durability) }
* and {@link #postDelete(ObserverContext, Delete, WALEdit, Durability) } is
* this hook will be executed before the mvcc transaction completion.
*
* Note: Do not retain references to any Cells in Mutations beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param miniBatchOp batch of Mutations applied to region. Coprocessors are discouraged from
* manipulating its state.
*/
// Coprocessors can do a form of bypass by changing state in miniBatchOp.
default void postBatchMutate(ObserverContext c,
MiniBatchOperationInProgress miniBatchOp) throws IOException {}
/**
* This will be called for region operations where read lock is acquired in
* {@link Region#startRegionOperation()}.
* @param ctx
* @param operation The operation is about to be taken on the region
*/
default void postStartRegionOperation(ObserverContext ctx,
Operation operation) throws IOException {}
/**
* Called after releasing read lock in {@link Region#closeRegionOperation()}.
* @param ctx
* @param operation
*/
default void postCloseRegionOperation(ObserverContext ctx,
Operation operation) throws IOException {}
/**
* Called after the completion of batch put/delete and will be called even if the batch operation
* fails.
*
* Note: Do not retain references to any Cells in Mutations beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param ctx
* @param miniBatchOp
* @param success true if batch operation is successful otherwise false.
*/
default void postBatchMutateIndispensably(ObserverContext ctx,
MiniBatchOperationInProgress miniBatchOp, boolean success) throws IOException {}
/**
* Called before checkAndPut.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'put' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param put data to put if check succeeds
* @param result
* @return the return value to return to client if bypassing default
* processing
*/
default boolean preCheckAndPut(ObserverContext c, byte[] row,
byte[] family, byte[] qualifier, CompareOperator op, ByteArrayComparable comparator, Put put,
boolean result) throws IOException {
return result;
}
/**
* Called before checkAndPut but after acquiring rowlock.
*
* Note: Caution to be taken for not doing any long time operation in this hook.
* Row will be locked for longer time. Trying to acquire lock on another row, within this,
* can lead to potential deadlock.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'put' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param put data to put if check succeeds
* @param result
* @return the return value to return to client if bypassing default
* processing
*/
default boolean preCheckAndPutAfterRowLock(ObserverContext c,
byte[] row, byte[] family, byte[] qualifier, CompareOperator op,
ByteArrayComparable comparator, Put put, boolean result) throws IOException {
return result;
}
/**
* Called after checkAndPut
*
* Note: Do not retain references to any Cells in 'put' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param put data to put if check succeeds
* @param result from the checkAndPut
* @return the possibly transformed return value to return to client
*/
default boolean postCheckAndPut(ObserverContext c, byte[] row,
byte[] family, byte[] qualifier, CompareOperator op, ByteArrayComparable comparator, Put put,
boolean result) throws IOException {
return result;
}
/**
* Called before checkAndDelete.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'delete' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param delete delete to commit if check succeeds
* @param result
* @return the value to return to client if bypassing default processing
*/
default boolean preCheckAndDelete(ObserverContext c, byte[] row,
byte[] family, byte[] qualifier, CompareOperator op, ByteArrayComparable comparator,
Delete delete, boolean result) throws IOException {
return result;
}
/**
* Called before checkAndDelete but after acquiring rowock.
*
* Note: Caution to be taken for not doing any long time operation in this hook.
* Row will be locked for longer time. Trying to acquire lock on another row, within this,
* can lead to potential deadlock.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'delete' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param delete delete to commit if check succeeds
* @param result
* @return the value to return to client if bypassing default processing
*/
default boolean preCheckAndDeleteAfterRowLock(ObserverContext c,
byte[] row, byte[] family, byte[] qualifier, CompareOperator op,
ByteArrayComparable comparator, Delete delete, boolean result) throws IOException {
return result;
}
/**
* Called after checkAndDelete
*
* Note: Do not retain references to any Cells in 'delete' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param row row to check
* @param family column family
* @param qualifier column qualifier
* @param op the comparison operation
* @param comparator the comparator
* @param delete delete to commit if check succeeds
* @param result from the CheckAndDelete
* @return the possibly transformed returned value to return to client
*/
default boolean postCheckAndDelete(ObserverContext c, byte[] row,
byte[] family, byte[] qualifier, CompareOperator op, ByteArrayComparable comparator,
Delete delete, boolean result) throws IOException {
return result;
}
/**
* Called before Append.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'append' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param append Append object
* @return result to return to the client if bypassing default processing
*/
default Result preAppend(ObserverContext c, Append append)
throws IOException {
return null;
}
/**
* Called before Append but after acquiring rowlock.
*
* Note: Caution to be taken for not doing any long time operation in this hook.
* Row will be locked for longer time. Trying to acquire lock on another row, within this,
* can lead to potential deadlock.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'append' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param append Append object
* @return result to return to the client if bypassing default processing
*/
default Result preAppendAfterRowLock(ObserverContext c,
Append append) throws IOException {
return null;
}
/**
* Called after Append
*
* Note: Do not retain references to any Cells in 'append' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param append Append object
* @param result the result returned by increment
* @return the result to return to the client
*/
default Result postAppend(ObserverContext c, Append append,
Result result) throws IOException {
return result;
}
/**
* Called before Increment.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'increment' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param increment increment object
* @return result to return to the client if bypassing default processing
*/
default Result preIncrement(ObserverContext c, Increment increment)
throws IOException {
return null;
}
/**
* Called before Increment but after acquiring rowlock.
*
* Note: Caution to be taken for not doing any long time operation in this hook.
* Row will be locked for longer time. Trying to acquire lock on another row, within this,
* can lead to potential deadlock.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells in 'increment' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
*
* @param c
* the environment provided by the region server
* @param increment
* increment object
* @return result to return to the client if bypassing default processing
* if an error occurred on the coprocessor
*/
default Result preIncrementAfterRowLock(ObserverContext c,
Increment increment) throws IOException {
return null;
}
/**
* Called after increment
*
* Note: Do not retain references to any Cells in 'increment' beyond the life of this invocation.
* If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param increment increment object
* @param result the result returned by increment
* @return the result to return to the client
*/
default Result postIncrement(ObserverContext c, Increment increment,
Result result) throws IOException {
return result;
}
/**
* Called before the client opens a new scanner.
*
* Note: Do not retain references to any Cells returned by scanner, beyond the life of this
* invocation. If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param scan the Scan specification
*/
default void preScannerOpen(ObserverContext c, Scan scan)
throws IOException {
}
/**
* Called after the client opens a new scanner.
*
* Note: Do not retain references to any Cells returned by scanner, beyond the life of this
* invocation. If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param scan the Scan specification
* @param s if not null, the base scanner
* @return the scanner instance to use
*/
default RegionScanner postScannerOpen(ObserverContext c, Scan scan,
RegionScanner s) throws IOException {
return s;
}
/**
* Called before the client asks for the next row on a scanner.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
*
* Note: Do not retain references to any Cells returned by scanner, beyond the life of this
* invocation. If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param s the scanner
* @param result The result to return to the client if default processing
* is bypassed. Can be modified. Will not be returned if default processing
* is not bypassed.
* @param limit the maximum number of results to return
* @param hasNext the 'has more' indication
* @return 'has more' indication that should be sent to client
*/
default boolean preScannerNext(ObserverContext c, InternalScanner s,
List result, int limit, boolean hasNext) throws IOException {
return hasNext;
}
/**
* Called after the client asks for the next row on a scanner.
*
* Note: Do not retain references to any Cells returned by scanner, beyond the life of this
* invocation. If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param s the scanner
* @param result the result to return to the client, can be modified
* @param limit the maximum number of results to return
* @param hasNext the 'has more' indication
* @return 'has more' indication that should be sent to client
*/
default boolean postScannerNext(ObserverContext c,
InternalScanner s, List result, int limit, boolean hasNext) throws IOException {
return hasNext;
}
/**
* This will be called by the scan flow when the current scanned row is being filtered out by the
* filter. The filter may be filtering out the row via any of the below scenarios
*
* -
*
boolean filterRowKey(byte [] buffer, int offset, int length) returning true
* -
*
boolean filterRow() returning true
* -
*
default void filterRow(List<KeyValue> kvs) removing all the kvs from
* the passed List
*
*
* Note: Do not retain references to any Cells returned by scanner, beyond the life of this
* invocation. If need a Cell reference for later use, copy the cell and use that.
* @param c the environment provided by the region server
* @param s the scanner
* @param curRowCell The cell in the current row which got filtered out
* @param hasMore the 'has more' indication
* @return whether more rows are available for the scanner or not
*/
default boolean postScannerFilterRow(ObserverContext c,
InternalScanner s, Cell curRowCell, boolean hasMore) throws IOException {
return hasMore;
}
/**
* Called before the client closes a scanner.
*
* Call CoprocessorEnvironment#bypass to skip default actions.
* If 'bypass' is set, we skip out on calling any subsequent chained coprocessors.
* @param c the environment provided by the region server
* @param s the scanner
*/
default void preScannerClose(ObserverContext c, InternalScanner s)
throws IOException {}
/**
* Called after the client closes a scanner.
* @param ctx the environment provided by the region server
* @param s the scanner
*/
default void postScannerClose(ObserverContext ctx,
InternalScanner s) throws IOException {}
/**
* Called before a store opens a new scanner.
*
* This hook is called when a "user" scanner is opened. Use {@code preFlushScannerOpen} and
* {@code preCompactScannerOpen} to inject flush/compaction.
*
* Notice that, this method is used to change the inherent max versions and TTL for a Store. For
* example, you can change the max versions option for a {@link Scan} object to 10 in
* {@code preScannerOpen}, but if the max versions config on the Store is 1, then you still can
* only read 1 version. You need also to inject here to change the max versions to 10 if you want
* to get more versions.
* @param ctx the environment provided by the region server
* @param store the store which we want to get scanner from
* @param options used to change max versions and TTL for the scanner being opened
* @see #preFlushScannerOpen(ObserverContext, Store, ScanOptions, FlushLifeCycleTracker)
* @see #preCompactScannerOpen(ObserverContext, Store, ScanType, ScanOptions,
* CompactionLifeCycleTracker, CompactionRequest)
*/
default void preStoreScannerOpen(ObserverContext ctx, Store store,
ScanOptions options) throws IOException {}
/**
* Called before replaying WALs for this region.
* Calling {@link org.apache.hadoop.hbase.coprocessor.ObserverContext#bypass()} has no
* effect in this hook.
* @param ctx the environment provided by the region server
* @param info the RegionInfo for this region
* @param edits the file of recovered edits
*/
// todo: what about these?
default void preReplayWALs(ObserverContext ctx,
RegionInfo info, Path edits) throws IOException {}
/**
* Called after replaying WALs for this region.
* @param ctx the environment provided by the region server
* @param info the RegionInfo for this region
* @param edits the file of recovered edits
*/
default void postReplayWALs(ObserverContext ctx,
RegionInfo info, Path edits) throws IOException {}
/**
* Called before a {@link WALEdit}
* replayed for this region.
* @param ctx the environment provided by the region server
*/
default void preWALRestore(ObserverContext ctx,
RegionInfo info, WALKey logKey, WALEdit logEdit) throws IOException {}
/**
* Called after a {@link WALEdit}
* replayed for this region.
* @param ctx the environment provided by the region server
*/
default void postWALRestore(ObserverContext ctx,
RegionInfo info, WALKey logKey, WALEdit logEdit) throws IOException {}
/**
* Called before bulkLoadHFile. Users can create a StoreFile instance to
* access the contents of a HFile.
*
* @param ctx the environment provided by the region server
* @param familyPaths pairs of { CF, HFile path } submitted for bulk load. Adding
* or removing from this list will add or remove HFiles to be bulk loaded.
*/
default void preBulkLoadHFile(ObserverContext ctx,
List> familyPaths) throws IOException {}
/**
* Called before moving bulk loaded hfile to region directory.
*
* @param ctx the environment provided by the region server
* @param family column family
* @param pairs List of pairs of { HFile location in staging dir, HFile path in region dir }
* Each pair are for the same hfile.
*/
default void preCommitStoreFile(ObserverContext ctx, byte[] family,
List> pairs) throws IOException {}
/**
* Called after moving bulk loaded hfile to region directory.
*
* @param ctx the environment provided by the region server
* @param family column family
* @param srcPath Path to file before the move
* @param dstPath Path to file after the move
*/
default void postCommitStoreFile(ObserverContext ctx, byte[] family,
Path srcPath, Path dstPath) throws IOException {}
/**
* Called after bulkLoadHFile.
*
* @param ctx the environment provided by the region server
* @param stagingFamilyPaths pairs of { CF, HFile path } submitted for bulk load
* @param finalPaths Map of CF to List of file paths for the loaded files
* if the Map is not null, the bulkLoad was successful. Otherwise the bulk load failed.
* bulkload is done by the time this hook is called.
*/
default void postBulkLoadHFile(ObserverContext ctx,
List> stagingFamilyPaths, Map> finalPaths)
throws IOException {
}
/**
* Called before creation of Reader for a store file.
* Calling {@link org.apache.hadoop.hbase.coprocessor.ObserverContext#bypass()} has no
* effect in this hook.
*
* @param ctx the environment provided by the region server
* @param fs fileystem to read from
* @param p path to the file
* @param in {@link FSDataInputStreamWrapper}
* @param size Full size of the file
* @param cacheConf
* @param r original reference file. This will be not null only when reading a split file.
* @param reader the base reader, if not {@code null}, from previous RegionObserver in the chain
* @return a Reader instance to use instead of the base reader if overriding
* default behavior, null otherwise
* @deprecated For Phoenix only, StoreFileReader is not a stable interface.
*/
@Deprecated
// Passing InterfaceAudience.Private args FSDataInputStreamWrapper, CacheConfig and Reference.
// This is fine as the hook is deprecated any way.
default StoreFileReader preStoreFileReaderOpen(ObserverContext ctx,
FileSystem fs, Path p, FSDataInputStreamWrapper in, long size, CacheConfig cacheConf,
Reference r, StoreFileReader reader) throws IOException {
return reader;
}
/**
* Called after the creation of Reader for a store file.
*
* @param ctx the environment provided by the region server
* @param fs fileystem to read from
* @param p path to the file
* @param in {@link FSDataInputStreamWrapper}
* @param size Full size of the file
* @param cacheConf
* @param r original reference file. This will be not null only when reading a split file.
* @param reader the base reader instance
* @return The reader to use
* @deprecated For Phoenix only, StoreFileReader is not a stable interface.
*/
@Deprecated
// Passing InterfaceAudience.Private args FSDataInputStreamWrapper, CacheConfig and Reference.
// This is fine as the hook is deprecated any way.
default StoreFileReader postStoreFileReaderOpen(ObserverContext ctx,
FileSystem fs, Path p, FSDataInputStreamWrapper in, long size, CacheConfig cacheConf,
Reference r, StoreFileReader reader) throws IOException {
return reader;
}
/**
* Called after a new cell has been created during an increment operation, but before
* it is committed to the WAL or memstore.
* Calling {@link org.apache.hadoop.hbase.coprocessor.ObserverContext#bypass()} has no
* effect in this hook.
* @param ctx the environment provided by the region server
* @param opType the operation type
* @param mutation the current mutation
* @param oldCell old cell containing previous value
* @param newCell the new cell containing the computed value
* @return the new cell, possibly changed
*/
default Cell postMutationBeforeWAL(ObserverContext ctx,
MutationType opType, Mutation mutation, Cell oldCell, Cell newCell) throws IOException {
return newCell;
}
/**
* Called after the ScanQueryMatcher creates ScanDeleteTracker. Implementing
* this hook would help in creating customised DeleteTracker and returning
* the newly created DeleteTracker
*
* Warn: This is used by internal coprocessors. Should not be implemented by user coprocessors
* @param ctx the environment provided by the region server
* @param delTracker the deleteTracker that is created by the QueryMatcher
* @return the Delete Tracker
* @deprecated Since 2.0 with out any replacement and will be removed in 3.0
*/
@Deprecated
default DeleteTracker postInstantiateDeleteTracker(
ObserverContext ctx, DeleteTracker delTracker)
throws IOException {
return delTracker;
}
}
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