com.mysql.cj.jdbc.ha.plugins.failover

Class ClusterAwareReaderFailoverHandler

java.lang.Object

com.mysql.cj.jdbc.ha.plugins.failover.ClusterAwareReaderFailoverHandler

All Implemented Interfaces:

IReaderFailoverHandler

public class ClusterAwareReaderFailoverHandler
extends java.lang.Object
implements IReaderFailoverHandler

An implementation of ReaderFailoverHandler.

Reader Failover Process goal is to connect to any available reader. In order to connect faster, this implementation tries to connect to two readers at the same time. The first successfully connected reader is returned as the process result. If both readers are unavailable (i.e. could not be connected to), the process picks up another pair of readers and repeat. If no reader has been connected to, the process may consider a writer host, and other hosts marked down, to connect to.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ClusterAwareReaderFailoverHandler.HostTuple HostTuple class.

Field Summary

Fields

Modifier and Type	Field and Description
protected IConnectionProvider	connProvider
protected static int	DEFAULT_FAILOVER_TIMEOUT
protected static int	DEFAULT_READER_CONNECT_TIMEOUT
protected boolean	enableFailoverStrictReader
protected java.util.Map<java.lang.String,java.lang.String>	initialConnectionProps
protected Log	log The logger we're going to use.
protected int	maxFailoverTimeoutMs
protected static Log	NULL_LOGGER Null logger shared by all connections at startup.
protected int	timeoutMs
protected ITopologyService	topologyService

Constructor Summary

Constructors

Constructor and Description
ClusterAwareReaderFailoverHandler(ITopologyService topologyService, IConnectionProvider connProvider, java.util.Map<java.lang.String,java.lang.String> initialConnectionProps, int failoverTimeoutMs, int timeoutMs, boolean enableFailoverStrictReader, Log log) ClusterAwareReaderFailoverHandler constructor.
ClusterAwareReaderFailoverHandler(ITopologyService topologyService, IConnectionProvider connProvider, java.util.Map<java.lang.String,java.lang.String> initialConnectionProps, Log log) ClusterAwareReaderFailoverHandler constructor.

Method Summary

Modifier and Type	Method and Description
ReaderFailoverResult	failover(java.util.List<HostInfo> hosts, HostInfo currentHost) Called to start Reader Failover Process.
protected ReaderFailoverResult	failoverInternal(java.util.List<HostInfo> hosts, HostInfo currentHost)
java.util.List<ClusterAwareReaderFailoverHandler.HostTuple>	getHostTuplesByPriority(java.util.List<HostInfo> hosts, java.util.Set<java.lang.String> downHosts)
ReaderFailoverResult	getReaderConnection(java.util.List<HostInfo> hostList) Called to get any available reader connection.
java.util.List<ClusterAwareReaderFailoverHandler.HostTuple>	getReaderTuplesByPriority(java.util.List<HostInfo> hostList, java.util.Set<java.lang.String> downHosts)
protected void	setTimeoutMs(int timeoutMs) Set process timeout in millis.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_FAILOVER_TIMEOUT

protected static final int DEFAULT_FAILOVER_TIMEOUT

See Also:

Constant Field Values

DEFAULT_READER_CONNECT_TIMEOUT

protected static final int DEFAULT_READER_CONNECT_TIMEOUT

See Also:

Constant Field Values

NULL_LOGGER

protected static final Log NULL_LOGGER

Null logger shared by all connections at startup.

log

protected transient Log log

The logger we're going to use.

initialConnectionProps

protected java.util.Map<java.lang.String,java.lang.String> initialConnectionProps

maxFailoverTimeoutMs

protected int maxFailoverTimeoutMs

timeoutMs

protected int timeoutMs

enableFailoverStrictReader

protected boolean enableFailoverStrictReader

connProvider

protected final IConnectionProvider connProvider

topologyService

protected final ITopologyService topologyService

Constructor Detail

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(ITopologyService topologyService,
                                         IConnectionProvider connProvider,
                                         java.util.Map<java.lang.String,java.lang.String> initialConnectionProps,
                                         Log log)

ClusterAwareReaderFailoverHandler constructor.

Parameters:

topologyService - An implementation of ITopologyService that obtains and caches a cluster's topology.

connProvider - A provider for creating new connections.

initialConnectionProps - The initial connection properties to copy over to the new reader.

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(ITopologyService topologyService,
                                         IConnectionProvider connProvider,
                                         java.util.Map<java.lang.String,java.lang.String> initialConnectionProps,
                                         int failoverTimeoutMs,
                                         int timeoutMs,
                                         boolean enableFailoverStrictReader,
                                         Log log)

ClusterAwareReaderFailoverHandler constructor.

Parameters:

topologyService - An implementation of ITopologyService that obtains and caches a cluster's topology.

connProvider - A provider for creating new connections.

initialConnectionProps - The initial connection properties to copy over to the new reader.

failoverTimeoutMs - Maximum allowed time in milliseconds to attempt reconnecting to a new reader instance after a cluster failover is initiated.

timeoutMs - Maximum allowed time for the entire reader failover process.

log - An implementation of Log.

Method Detail

setTimeoutMs

protected void setTimeoutMs(int timeoutMs)

Set process timeout in millis. Entire process of connecting to a reader will be limited by this time duration.

Parameters:

timeoutMs - Process timeout in millis

failover

public ReaderFailoverResult failover(java.util.List<HostInfo> hosts,
                                     HostInfo currentHost)
                              throws java.sql.SQLException

Called to start Reader Failover Process. This process tries to connect to any reader. If no reader is available then driver may also try to connect to a writer host, down hosts, and the current reader host.

Specified by:

failover in interface IReaderFailoverHandler

Parameters:

hosts - Cluster current topology

currentHost - The currently connected host that has failed.

Returns:

ReaderFailoverResult The results of this process.

Throws:

java.sql.SQLException

failoverInternal

protected ReaderFailoverResult failoverInternal(java.util.List<HostInfo> hosts,
                                                HostInfo currentHost)
                                         throws java.sql.SQLException

Throws:

java.sql.SQLException

getHostTuplesByPriority

public java.util.List<ClusterAwareReaderFailoverHandler.HostTuple> getHostTuplesByPriority(java.util.List<HostInfo> hosts,
                                                                                           java.util.Set<java.lang.String> downHosts)

getReaderConnection

public ReaderFailoverResult getReaderConnection(java.util.List<HostInfo> hostList)
                                         throws java.sql.SQLException

Called to get any available reader connection. If no reader is available then result of process is unsuccessful. This process will not attempt to connect to the writer.

Specified by:

getReaderConnection in interface IReaderFailoverHandler

Parameters:

hostList - Cluster current topology

Returns:

ReaderFailoverResult The results of this process.

Throws:

java.sql.SQLException

getReaderTuplesByPriority

public java.util.List<ClusterAwareReaderFailoverHandler.HostTuple> getReaderTuplesByPriority(java.util.List<HostInfo> hostList,
                                                                                             java.util.Set<java.lang.String> downHosts)