接続先DBをSQLの内容等で振り分け
概要
・負荷分散、データ分割などの理由で接続先のDBを振り分けたい
・org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource を利用
・MyBatis のSQL実行をインターセプト
環境
・SpringFramework 4
・mybatis 3.2
・mybatis-spring 1.2
・mysql (jdbc)
構成
・Source/Replica (Master/Slave)
・デフォルトは Source の方に接続、特別な場合に Replica の方へ接続するなどコードで色々設定が可能
・インターセプターで接続先を設定する
コード
DynamicDataSource
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
public class DynamicDataSource extends AbstractRoutingDataSource {
@Override
protected Object determineCurrentLookupKey() {
return DynamicDataSourceHolder.getDbType();
}
}
DynamicDataSourceHolder
Source/Replica でなく Master/Slave になっていますが…
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class DynamicDataSourceHolder {
public static final String DB_MASTER = "master";
public static final String DB_SLAVE = "slave";
private static Logger logger = LoggerFactory.getLogger(DynamicDataSourceHolder.class);
private static ThreadLocal<String> contextHolder = new ThreadLocal<>();
public static Object getDbType() {
String dbType = contextHolder.get();
if (dbType == null) {
return DB_MASTER;
}
return dbType;
}
public static void setDbType(String dbType) {
contextHolder.set(dbType);
}
public static void clearDbType() {
contextHolder.remove();
}
}
DynamicDataSourceInterceptor
・REGEX_WRITE の場合は Source(Master) の方へ接続
・更新系を分けていますが、SELECTから始まるSQLを replica(slave) へする等色々条件は変更が可能
import java.util.Properties;
import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.executor.keygen.SelectKeyGenerator;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.support.TransactionSynchronizationManager;
@Intercepts({
@Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class }),
@Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class }),
@Signature(type = Executor.class, method = "update", args = { MappedStatement.class, Object.class }), })
public class DynamicDataSourceInterceptor implements Interceptor {
private static Logger logger = LoggerFactory.getLogger(DynamicDataSourceInterceptor.class);
private static final String REGEX_WRITE = ".*update\\u0020.*|.*insert\\u0020.*|.*delete\\u0020.*|.*load\\u0020.*";
@Override
public Object intercept(Invocation invocation) throws Throwable {
boolean synchronizationActive = TransactionSynchronizationManager.isSynchronizationActive();
Object[] args = invocation.getArgs();
MappedStatement ms = (MappedStatement) args[0];
String lookupKey = "";
if (!synchronizationActive) {
if (ms.getSqlCommandType().equals(SqlCommandType.SELECT)) {
if (ms.getId().contains(SelectKeyGenerator.SELECT_KEY_SUFFIX)) {
lookupKey = DynamicDataSourceHolder.DB_MASTER;
}
else {
lookupKey = DynamicDataSourceHolder.DB_SLAVE;
}
}
else {
BoundSql boundSql = ms.getSqlSource().getBoundSql(args[1]);
String sql = boundSql.getSql().toLowerCase().replaceAll("[\\t\\n\\r]", " ");
if (sql.matches(REGEX_WRITE)) {
lookupKey = DynamicDataSourceHolder.DB_MASTER;
}
else {
lookupKey = DynamicDataSourceHolder.DB_SLAVE;
}
}
}
else {
lookupKey = DynamicDataSourceHolder.DB_MASTER;
}
DynamicDataSourceHolder.setDbType(lookupKey);
// Execution proceed
long startTime = System.currentTimeMillis();
Object returnValue = invocation.proceed();
long elapsedTime = System.currentTimeMillis() - startTime;
logger.debug(String.format("Method [%s] use [%s] Strategy, SqlType [%s], Time [%s]ms.",
ms.getId(), lookupKey, ms.getSqlCommandType().name(), elapsedTime));
return returnValue;
}
@Override
public Object plugin(Object target) {
if (target instanceof Executor) {
return Plugin.wrap(target, this);
}
return target;
}
@Override
public void setProperties(Properties properties) {
// nop
}
}
Mapper メソッド名で分ける
・上記の DynamicDataSourceInterceptor（一部割愛）
・振り分けの割合も設定してみたり (7:3)
private static final String[] SLAVE_METHOD_IDS = {
"your.project.domain.SampleMapper.countSqlSample",
"your.project.domain.SampleMapper.selectSqlSample"
};
@Override
public Object intercept(Invocation invocation) throws Throwable {
boolean synchronizationActive = TransactionSynchronizationManager.isSynchronizationActive();
Object[] args = invocation.getArgs();
MappedStatement ms = (MappedStatement) args[0];
String lookupKey = "";
if (!synchronizationActive) {
// 特定のSQLのみSLAVE実行
String methodId = ms.getId();
for (String method: SLAVE_METHOD_IDS) {
if (Objects.equals(method, methodId)) {
int max = 10;
int min = 1;
Random r = new Random();
int which = r.nextInt((max - min) + 1) + min;
// 7
if (which > 3) {
lookupKey = DynamicDataSourceHolder.DB_SLAVE;
}
// 3
else {
lookupKey = DynamicDataSourceHolder.DB_MASTER;
}
break;
}
}
}
else {
lookupKey = DynamicDataSourceHolder.DB_MASTER;
}
DynamicDataSourceHolder.setDbType(lookupKey);
// Execution proceed
long startTime = System.currentTimeMillis();
Object returnValue = invocation.proceed();
long elapsedTime = System.currentTimeMillis() - startTime;
logger.debug(String.format("Method [%s] use [%s] Strategy, SqlType [%s], Time [%s]ms.",
ms.getId(), lookupKey, ms.getSqlCommandType().name(), elapsedTime));
return returnValue;
}
jdbc 設定
・properties にユーザなどの接続設定を記載しているものとします
<bean id="sample.dataSource.master" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.master.url}" />
<property name="username" value="${jdbc.master.username}" />
<property name="password" value="${jdbc.master.password}" />
...途中割愛...
</bean>
<bean id="sample.dataSource.slave" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.slave.url}" />
<property name="username" value="${jdbc.slave.username}" />
<property name="password" value="${jdbc.slave.password}" />
...途中割愛...
</bean>
<bean id="sample.dataSource" class="your.project.domain.springframework.data.DynamicDataSource">
<property name="targetDataSources">
<map key-type="java.lang.String">
<entry key="master" value-ref="sample.dataSource.master" />
<entry key="slave" value-ref="sample.dataSource.slave" />
</map>
</property>
<property name="defaultTargetDataSource" ref="sample.dataSource.master" />
</bean>
<bean id="sample.sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="sample.dataSource" />
<property name="plugins">
<array>
<bean class="your.project.domain.springframework.data.DynamicDataSourceInterceptor" />
</array>
</property>
</bean>
<bean id="sample.sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate" scope="prototype">
<constructor-arg index="0" ref="sample.sqlSessionFactory" />
</bean>
以上、お疲れ様でした！