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/*
* Copyright (c) 2010, 2020, Oracle and/or its affiliates.
*
* 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.Properties;
import java.util.function.Supplier;
import com.mysql.cj.MysqlConnection;
import com.mysql.cj.Query;
import com.mysql.cj.conf.PropertyKey;
import com.mysql.cj.exceptions.ExceptionFactory;
import com.mysql.cj.interceptors.QueryInterceptor;
import com.mysql.cj.jdbc.JdbcConnection;
import com.mysql.cj.log.Log;
import com.mysql.cj.protocol.Resultset;
import com.mysql.cj.protocol.ServerSession;
import com.mysql.cj.util.StringUtils;
public class LoadBalancedAutoCommitInterceptor implements QueryInterceptor {
private int matchingAfterStatementCount = 0;
private int matchingAfterStatementThreshold = 0;
private String matchingAfterStatementRegex;
private JdbcConnection conn;
private LoadBalancedConnectionProxy proxy = null;
private boolean countStatements = false;
@Override
public void destroy() {
this.conn = null;
this.proxy = null;
}
@Override
public boolean executeTopLevelOnly() {
// always return false
return false;
}
@Override
public QueryInterceptor init(MysqlConnection connection, Properties props, Log log) {
this.conn = (JdbcConnection) connection;
String autoCommitSwapThresholdAsString = props.getProperty(PropertyKey.loadBalanceAutoCommitStatementThreshold.getKeyName(), "0");
try {
this.matchingAfterStatementThreshold = Integer.parseInt(autoCommitSwapThresholdAsString);
} catch (NumberFormatException nfe) {
// nothing here, being handled in LoadBalancedConnectionProxy.
}
String autoCommitSwapRegex = props.getProperty(PropertyKey.loadBalanceAutoCommitStatementRegex.getKeyName(), "");
if (!"".equals(autoCommitSwapRegex)) {
this.matchingAfterStatementRegex = autoCommitSwapRegex;
}
return this;
}
@Override
@SuppressWarnings("resource")
public T postProcess(Supplier sql, Query interceptedQuery, T originalResultSet, ServerSession serverSession) {
try {
// Don't count SETs, SHOWs neither USEs. Those are mostly used internally and must not trigger a connection switch.
if (!this.countStatements || StringUtils.startsWithIgnoreCase(sql.get(), "SET") || StringUtils.startsWithIgnoreCase(sql.get(), "SHOW")
|| StringUtils.startsWithIgnoreCase(sql.get(), "USE")) {
return originalResultSet;
}
// Don't care if auto-commit is not enabled.
if (!this.conn.getAutoCommit()) {
this.matchingAfterStatementCount = 0;
return originalResultSet;
}
if (this.proxy == null && this.conn.isProxySet()) {
JdbcConnection connParentProxy = this.conn.getMultiHostParentProxy();
while (connParentProxy != null && !(connParentProxy instanceof LoadBalancedMySQLConnection)) {
connParentProxy = connParentProxy.getMultiHostParentProxy();
}
if (connParentProxy != null) {
this.proxy = ((LoadBalancedMySQLConnection) connParentProxy).getThisAsProxy();
}
}
// Connection is not ready to rebalance yet.
if (this.proxy == null) {
return originalResultSet;
}
// Increment the match count if no regex specified, or if matches.
if (this.matchingAfterStatementRegex == null || sql.get().matches(this.matchingAfterStatementRegex)) {
this.matchingAfterStatementCount++;
}
// Trigger rebalance if count exceeds threshold.
if (this.matchingAfterStatementCount >= this.matchingAfterStatementThreshold) {
this.matchingAfterStatementCount = 0;
try {
this.proxy.pickNewConnection();
} catch (SQLException e) {
// eat this exception, the auto-commit statement completed, but we could not rebalance for some reason. User may get exception when using
// connection next.
}
}
} catch (SQLException ex) {
throw ExceptionFactory.createException(ex.getMessage(), ex);
}
// always return the original result set.
return originalResultSet;
}
@Override
public T preProcess(Supplier sql, Query interceptedQuery) {
// we do nothing before execution, it's unsafe to swap servers at this point.
return null;
}
void pauseCounters() {
this.countStatements = false;
}
void resumeCounters() {
this.countStatements = true;
}
}
