org.apache.accumulo.gc.replication

Class CloseWriteAheadLogReferences

java.lang.Object

org.apache.accumulo.gc.replication.CloseWriteAheadLogReferences

All Implemented Interfaces:

Runnable

public class CloseWriteAheadLogReferences
extends Object
implements Runnable

It's impossible to know when all references to a WAL have been removed from the metadata table as the references are potentially spread across the entire tablets row-space.

This tool scans the metadata table to collect a set of WALs that are still referenced. Then, each Replication.Status record from the metadata and replication tables that point to that WAL can be "closed", by writing a new Status to the same key with the closed member true.

Constructor Summary

Constructors

Constructor and Description
CloseWriteAheadLogReferences(AccumuloServerContext context)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	closeWal(BatchWriter bw, Key k) Write a closed Replication.Status mutation for the given Key using the provided BatchWriter
protected List<String>	getActiveTservers(TInfo tinfo) Get the active tabletservers as seen by the master.
protected Set<String>	getActiveWals(TInfo tinfo) Fetch the set of WALs in use by tabletservers
protected List<String>	getActiveWalsForServer(TInfo tinfo, com.google.common.net.HostAndPort server)
protected HashSet<String>	getReferencedWals(Connector conn) Construct the set of referenced WALs from the metadata table
void	run()
protected long	updateReplicationEntries(Connector conn, Set<String> referencedWals) Given the set of WALs which have references in the metadata table, close any status messages with reference that WAL.

Methods inherited from class java.lang.Object

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

Constructor Detail

CloseWriteAheadLogReferences

public CloseWriteAheadLogReferences(AccumuloServerContext context)

Method Detail

run

public void run()

Specified by:

run in interface Runnable

getReferencedWals

protected HashSet<String> getReferencedWals(Connector conn)

Construct the set of referenced WALs from the metadata table

Parameters:

conn - Connector

Returns:

The Set of WALs that are referenced in the metadata table

updateReplicationEntries

protected long updateReplicationEntries(Connector conn,
                            Set<String> referencedWals)

Given the set of WALs which have references in the metadata table, close any status messages with reference that WAL.

Parameters:

conn - Connector

referencedWals - Set of paths to WALs that are referenced in the tablets section of the metadata table

closeWal

protected void closeWal(BatchWriter bw,
            Key k)
                 throws MutationsRejectedException

Write a closed Replication.Status mutation for the given Key using the provided BatchWriter

Parameters:

bw - BatchWriter

k - Key to create close mutation from

Throws:

MutationsRejectedException

getActiveWals

protected Set<String> getActiveWals(TInfo tinfo)

Fetch the set of WALs in use by tabletservers

Returns:

Set of WALs in use by tservers, null if they cannot be computed for some reason

getActiveTservers

protected List<String> getActiveTservers(TInfo tinfo)

Get the active tabletservers as seen by the master.

Returns:

The active tabletservers, null if they can't be computed.

getActiveWalsForServer

protected List<String> getActiveWalsForServer(TInfo tinfo,
                                  com.google.common.net.HostAndPort server)