org.apache.hadoop.hbase.regionserver.wal

Class WALUtil

java.lang.Object

org.apache.hadoop.hbase.regionserver.wal.WALUtil

@InterfaceAudience.Private
public class WALUtil
extends Object

Helper methods to ease Region Server integration with the write ahead log. Note that methods in this class specifically should not require access to anything other than the API found in WAL.

Constructor Summary

Constructors

Constructor and Description
WALUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static long	writeBulkLoadMarkerAndSync(WAL wal, HTableDescriptor htd, HRegionInfo info, WALProtos.BulkLoadDescriptor descriptor, AtomicLong sequenceId) Write a log marker that a bulk load has succeeded and is about to be committed.
static void	writeCompactionMarker(WAL log, HTableDescriptor htd, HRegionInfo info, WALProtos.CompactionDescriptor c, AtomicLong sequenceId) Write the marker that a compaction has succeeded and is about to be committed.
static long	writeFlushMarker(WAL log, HTableDescriptor htd, HRegionInfo info, WALProtos.FlushDescriptor f, AtomicLong sequenceId, boolean sync) Write a flush marker indicating a start / abort or a complete of a region flush
static long	writeRegionEventMarker(WAL log, HTableDescriptor htd, HRegionInfo info, WALProtos.RegionEventDescriptor r, AtomicLong sequenceId) Write a region open marker indicating that the region is opened

Methods inherited from class java.lang.Object

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

Constructor Detail

WALUtil

public WALUtil()

Method Detail

writeCompactionMarker

public static void writeCompactionMarker(WAL log,
                         HTableDescriptor htd,
                         HRegionInfo info,
                         WALProtos.CompactionDescriptor c,
                         AtomicLong sequenceId)
                                  throws IOException

Write the marker that a compaction has succeeded and is about to be committed. This provides info to the HMaster to allow it to recover the compaction if this regionserver dies in the middle (This part is not yet implemented). It also prevents the compaction from finishing if this regionserver has already lost its lease on the log.

Parameters:

sequenceId - Used by WAL to get sequence Id for the waledit.

Throws:

IOException

writeFlushMarker

public static long writeFlushMarker(WAL log,
                    HTableDescriptor htd,
                    HRegionInfo info,
                    WALProtos.FlushDescriptor f,
                    AtomicLong sequenceId,
                    boolean sync)
                             throws IOException

Write a flush marker indicating a start / abort or a complete of a region flush

Throws:

IOException

writeRegionEventMarker

public static long writeRegionEventMarker(WAL log,
                          HTableDescriptor htd,
                          HRegionInfo info,
                          WALProtos.RegionEventDescriptor r,
                          AtomicLong sequenceId)
                                   throws IOException

Write a region open marker indicating that the region is opened

Throws:

IOException

writeBulkLoadMarkerAndSync

public static long writeBulkLoadMarkerAndSync(WAL wal,
                              HTableDescriptor htd,
                              HRegionInfo info,
                              WALProtos.BulkLoadDescriptor descriptor,
                              AtomicLong sequenceId)
                                       throws IOException

Write a log marker that a bulk load has succeeded and is about to be committed.

Parameters:

wal - The log to write into.

htd - A description of the table that we are bulk loading into.

info - A description of the region in the table that we are bulk loading into.

descriptor - A protocol buffers based description of the client's bulk loading request

sequenceId - The current sequenceId in the log at the time when we were to write the bulk load marker.

Returns:

txid of this transaction or if nothing to do, the last txid

Throws:

IOException - We will throw an IOException if we can not append to the HLog.