com.mysql.cj.jdbc.ha.ca

Class ClusterAwareReaderFailoverHandler

java.lang.Object

com.mysql.cj.jdbc.ha.ca.ClusterAwareReaderFailoverHandler

All Implemented Interfaces:

ReaderFailoverHandler

public class ClusterAwareReaderFailoverHandler
extends java.lang.Object
implements ReaderFailoverHandler

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
protected static class	ClusterAwareReaderFailoverHandler.HostTuple HostTuple class.

Field Summary

Fields

Modifier and Type	Field and Description
protected ConnectionProvider	connProvider
protected static int	DEFAULT_FAILOVER_TIMEOUT
protected Log	log The logger we're going to use.
protected static Log	NULL_LOGGER Null logger shared by all connections at startup.
protected int	timeoutMs
protected TopologyService	topologyService

Constructor Summary

Constructors

Constructor and Description
ClusterAwareReaderFailoverHandler(TopologyService topologyService, ConnectionProvider connProvider, int timeoutMs, Log log) ClusterAwareReaderFailoverHandler constructor.
ClusterAwareReaderFailoverHandler(TopologyService topologyService, ConnectionProvider connProvider, Log log)

Method Summary

Modifier and Type	Method and Description
ConnectionAttemptResult	failover(java.util.List<HostInfo> hosts, HostInfo currentHost) Called to start Reader Failover Process.
ConnectionAttemptResult	getReaderConnection(java.util.List<HostInfo> hostList) Called to get any available reader connection.
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

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.

timeoutMs

protected int timeoutMs

connProvider

protected final ConnectionProvider connProvider

topologyService

protected final TopologyService topologyService

Constructor Detail

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(TopologyService topologyService,
                                         ConnectionProvider connProvider,
                                         Log log)

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(TopologyService topologyService,
                                         ConnectionProvider connProvider,
                                         int timeoutMs,
                                         Log log)

ClusterAwareReaderFailoverHandler constructor.

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 ConnectionAttemptResult 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 ReaderFailoverHandler

Parameters:

hosts - Cluster current topology

currentHost - The currently connected host that has failed.

Returns:

ConnectionAttemptResult The results of this process. May return null, which is considered an unsuccessful result.

Throws:

java.sql.SQLException

getReaderConnection

public ConnectionAttemptResult 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 ReaderFailoverHandler

Parameters:

hostList - Cluster current topology

Returns:

ConnectionAttemptResult The results of this process. May return null, which is considered an unsuccessful result.

Throws:

java.sql.SQLException