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JDBC Type 4 driver for MySQL
/*
* Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License, version 2.0, as published by the
* Free Software Foundation.
*
* This program is also distributed with certain software (including but not
* limited to OpenSSL) that is licensed under separate terms, as designated in a
* particular file or component or in included license documentation. The
* authors of MySQL hereby grant you an additional permission to link the
* program and your derivative works with the separately licensed software that
* they have included with MySQL.
*
* Without limiting anything contained in the foregoing, this file, which is
* part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
* version 1.0, a copy of which can be found at
* http://oss.oracle.com/licenses/universal-foss-exception.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
* for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.mysql.cj.jdbc.ha;
import java.sql.SQLException;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
/**
* Group of connection objects which can be configured as a group. This is used for promotion/demotion of slaves and masters in a replication configuration,
* and for exposing metrics around replication-aware connections.
*/
public class ReplicationConnectionGroup {
private String groupName;
private long connections = 0;
private long slavesAdded = 0;
private long slavesRemoved = 0;
private long slavesPromoted = 0;
private long activeConnections = 0;
private HashMap replicationConnections = new HashMap<>();
private Set slaveHostList = new CopyOnWriteArraySet<>();
private boolean isInitialized = false;
private Set masterHostList = new CopyOnWriteArraySet<>();
ReplicationConnectionGroup(String groupName) {
this.groupName = groupName;
}
public long getConnectionCount() {
return this.connections;
}
public long registerReplicationConnection(ReplicationConnection conn, List localMasterList, List localSlaveList) {
long currentConnectionId;
synchronized (this) {
if (!this.isInitialized) {
if (localMasterList != null) {
this.masterHostList.addAll(localMasterList);
}
if (localSlaveList != null) {
this.slaveHostList.addAll(localSlaveList);
}
this.isInitialized = true;
}
currentConnectionId = ++this.connections;
this.replicationConnections.put(Long.valueOf(currentConnectionId), conn);
}
this.activeConnections++;
return currentConnectionId;
}
public String getGroupName() {
return this.groupName;
}
public Collection getMasterHosts() {
return this.masterHostList;
}
public Collection getSlaveHosts() {
return this.slaveHostList;
}
/**
* Adds a host to the slaves hosts list.
*
* We can safely assume that if this host was added to the slaves list, then it must be added to each one of the replication connections from this group as
* well.
* Unnecessary calls to {@link ReplicationConnection#addSlaveHost(String)} could result in undesirable locking issues, assuming that this method is
* synchronized by nature.
*
* This is a no-op if the group already has this host in a slave role.
*
* @param hostPortPair
* "host:port"
* @throws SQLException
* if an error occurs
*/
public void addSlaveHost(String hostPortPair) throws SQLException {
// only add if it's not already a slave host
if (this.slaveHostList.add(hostPortPair)) {
this.slavesAdded++;
// add the slave to all connections:
for (ReplicationConnection c : this.replicationConnections.values()) {
c.addSlaveHost(hostPortPair);
}
}
}
public void handleCloseConnection(ReplicationConnection conn) {
this.replicationConnections.remove(conn.getConnectionGroupId());
this.activeConnections--;
}
/**
* Removes a host from the slaves hosts list.
*
* We can safely assume that if this host was removed from the slaves list, then it must be removed from each one of the replication connections from this
* group as well.
* Unnecessary calls to {@link ReplicationConnection#removeSlave(String, boolean)} could result in undesirable locking issues, assuming that this method is
* synchronized by nature.
*
* This is a no-op if the group doesn't have this host in a slave role.
*
* @param hostPortPair
* "host:port"
* @param closeGently
* remove host when it's not in use
* @throws SQLException
* if an error occurs
*/
public void removeSlaveHost(String hostPortPair, boolean closeGently) throws SQLException {
if (this.slaveHostList.remove(hostPortPair)) {
this.slavesRemoved++;
// remove the slave from all connections:
for (ReplicationConnection c : this.replicationConnections.values()) {
c.removeSlave(hostPortPair, closeGently);
}
}
}
/**
* Promotes a slave host to master.
*
* We can safely assume that if this host was removed from the slaves list or added to the masters list, then the same host promotion must happen in each
* one of the replication connections from this group as well.
* Unnecessary calls to {@link ReplicationConnection#promoteSlaveToMaster(String)} could result in undesirable locking issues, assuming that this method is
* synchronized by nature.
*
* This is a no-op if the group already has this host in a master role and not in slave role.
*
* @param hostPortPair
* "host:port"
* @throws SQLException
* if an error occurs
*/
public void promoteSlaveToMaster(String hostPortPair) throws SQLException {
// remove host from slaves AND add host to masters, note that both operands need to be evaluated.
if (this.slaveHostList.remove(hostPortPair) | this.masterHostList.add(hostPortPair)) {
this.slavesPromoted++;
for (ReplicationConnection c : this.replicationConnections.values()) {
c.promoteSlaveToMaster(hostPortPair);
}
}
}
/**
* Removes a host from the masters hosts list.
*
* @param hostPortPair
* host:port
* @throws SQLException
* if an error occurs
*/
public void removeMasterHost(String hostPortPair) throws SQLException {
this.removeMasterHost(hostPortPair, true);
}
/**
* Removes a host from the masters hosts list.
*
* We can safely assume that if this host was removed from the masters list, then it must be removed from each one of the replication connections from this
* group as well.
* Unnecessary calls to {@link ReplicationConnection#removeMasterHost(String, boolean)} could result in undesirable locking issues, assuming that this
* method is synchronized by nature.
*
* This is a no-op if the group doesn't have this host in a master role.
*
* @param hostPortPair
* "host:port"
* @param closeGently
* remove host when it's not in use
* @throws SQLException
* if an error occurs
*/
public void removeMasterHost(String hostPortPair, boolean closeGently) throws SQLException {
if (this.masterHostList.remove(hostPortPair)) {
// remove the master from all connections:
for (ReplicationConnection c : this.replicationConnections.values()) {
c.removeMasterHost(hostPortPair, closeGently);
}
}
}
public int getConnectionCountWithHostAsSlave(String hostPortPair) {
int matched = 0;
for (ReplicationConnection c : this.replicationConnections.values()) {
if (c.isHostSlave(hostPortPair)) {
matched++;
}
}
return matched;
}
public int getConnectionCountWithHostAsMaster(String hostPortPair) {
int matched = 0;
for (ReplicationConnection c : this.replicationConnections.values()) {
if (c.isHostMaster(hostPortPair)) {
matched++;
}
}
return matched;
}
public long getNumberOfSlavesAdded() {
return this.slavesAdded;
}
public long getNumberOfSlavesRemoved() {
return this.slavesRemoved;
}
public long getNumberOfSlavePromotions() {
return this.slavesPromoted;
}
public long getTotalConnectionCount() {
return this.connections;
}
public long getActiveConnectionCount() {
return this.activeConnections;
}
@Override
public String toString() {
return "ReplicationConnectionGroup[groupName=" + this.groupName + ",masterHostList=" + this.masterHostList + ",slaveHostList=" + this.slaveHostList
+ "]";
}
}