Linliangkung opened a new issue #9115:
URL: https://github.com/apache/shardingsphere/issues/9115
AbstractConnectionAdapter.createConnections方法（问题描述在代码块注释中）
``` java
private List<Connection> createConnections(final String dataSourceName,
final ConnectionMode connectionMode, final DataSource dataSource, final int
connectionSize) throws SQLException {
if (1 == connectionSize) {
Connection connection = createConnection(dataSourceName,
dataSource);
replayMethodsInvocation(connection);
return Collections.singletonList(connection);
}
if (ConnectionMode.CONNECTION_STRICTLY == connectionMode) {
//CONNECTION_STRICTLY 模式下为什么没有加synchronized代码块
//假设我的connectionSize为2，数据源最大线程数是2
//现在有两个线程A和线程B同时执行下面的createConnections方法
//如果线程A和线程B都同时拿到一个连接，然后再去拿第二个连接的时候就会出现占有一个连接，相互等待对方释放连接的情况出现
return createConnections(dataSourceName, dataSource,
connectionSize);
}
synchronized (dataSource) {
return createConnections(dataSourceName, dataSource,
connectionSize);
}
}
```
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