Package org.apache.hadoop.hbase.regionserver.handler

Class RegionReplicaFlushHandler

java.lang.Object

org.apache.hadoop.hbase.executor.EventHandler

org.apache.hadoop.hbase.regionserver.handler.RegionReplicaFlushHandler

All Implemented Interfaces:

Comparable<EventHandler>, Runnable

@Private
public class RegionReplicaFlushHandler
extends EventHandler

HBASE-11580: With the async wal approach (HBASE-11568), the edits are not persisted to WAL in secondary region replicas. This means that a secondary region replica can serve some edits from it's memstore that are still not flushed from primary. We do not want to allow secondary region's seqId to go back in time, when this secondary region is opened elsewhere after a crash or region move. We will trigger a flush cache in the primary region replica and wait for observing a complete flush cycle before marking the region readsEnabled. This handler does the flushing of the primary region replica and ensures that regular region opening is not blocked while the secondary replica is blocked on flush.

Field Summary

Fields

Modifier and Type	Field	Description
private final AsyncClusterConnection	connection
private static final org.slf4j.Logger	LOG
private final HRegion	region

Fields inherited from class org.apache.hadoop.hbase.executor.EventHandler

eventType, seqids, server, waitingTimeForEvents

Constructor Summary

Constructors

Constructor	Description
RegionReplicaFlushHandler(Server server, HRegion region)

Method Summary

Modifier and Type	Method	Description
private int	getRetriesCount(org.apache.hadoop.conf.Configuration conf)
protected void	handleException(Throwable t)	Event exception handler, may be overridden
void	process()	This method is the main processing loop to be implemented by the various subclasses.
(package private) void	triggerFlushInPrimaryRegion(HRegion region)

Methods inherited from class org.apache.hadoop.hbase.executor.EventHandler

compareTo, getEventType, getInformativeName, getPriority, getSeqid, prepare, run, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

LOG

private static final org.slf4j.Logger LOG

connection

private final AsyncClusterConnection connection

region

private final HRegion region

Constructor Details

RegionReplicaFlushHandler

public RegionReplicaFlushHandler(Server server,
 HRegion region)

Method Details

process

public void process()
             throws IOException

Description copied from class: EventHandler

This method is the main processing loop to be implemented by the various subclasses.

Specified by:

process in class EventHandler

Throws:

IOException

handleException

protected void handleException(Throwable t)

Description copied from class: EventHandler

Event exception handler, may be overridden

Overrides:

handleException in class EventHandler

Parameters:

t - Throwable object

getRetriesCount

private int getRetriesCount(org.apache.hadoop.conf.Configuration conf)

triggerFlushInPrimaryRegion

void triggerFlushInPrimaryRegion(HRegion region)
                          throws IOException

Throws:

IOException