背景项目使用 OceanBase 数据库并通过 ShardingSphere JDBC 实现分表。由于 ShardingSphere 当前不支持jdbc:oceanbase:协议我们在代码中将连接串替换为jdbc:mysql并引入 MySQL 驱动dependency groupIdcom.oceanbase/groupId artifactIdoceanbase-client/artifactId version2.4.8/version /dependency dependency groupIdorg.apache.shardingsphere/groupId artifactIdshardingsphere-jdbc/artifactId version5.5.2/version /dependency dependency groupIdcom.mysql/groupId artifactIdmysql-connector-j/artifactId !-- 问题根源 -- version8.4.0/version /dependency数据源配置如下关键部分spring: datasource: driver-class-name: com.oceanbase.jdbc.Driver url: jdbc:oceanbase:loadbalance://IP:PORT/test?... druid: initial-size: 8 max-active: 30 min-idle: 8Configuration public class ShardingDataSourceConfiguration { Value(${spring.datasource.url}) private String url; Value(${spring.datasource.username}) private String username; Value(${spring.datasource.password}) private String password; private MapString, DataSource createDataSourceMap() { MapString, DataSource dataSourceMap new HashMap(); DruidDataSource dataSource1 new DruidDataSource(); dataSource1.setDriverClassName(com.mysql.cj.jdbc.Driver); url url.replace(jdbc:oceanbase, jdbc:mysql); dataSource1.setUrl(url); dataSource1.setUsername(username); dataSource1.setPassword(password); dataSource1.setInitialSize(8); dataSource1.setMaxActive(30); dataSource1.setMinIdle(8); dataSourceMap.put(ds_0, dataSource1); return dataSourceMap; } Bean(shardingDataSource) public DataSource dataSource() throws SQLException { Properties props new Properties(); props.put(sql-show, false); return ShardingSphereDataSourceFactory.createDataSource( createDataSourceMap(), Collections.singletonList(createShardingRuleConfiguration()), props ); } }同时项目中还有一个未经过 ShardingSphere 的原生 OceanBase 数据源Configuration public class DataSourceConfiguration { Bean(name logAnalysisDataSource) public DataSource logAnalysisDataSource() { // com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder // 使用 spring.datasource 配置来创建数据库连接池 DruidDataSource druidDataSource DruidDataSourceBuilder.create().build(); druidDataSource.setSocketTimeout(180000); druidDataSource.setConnectTimeout(180000); return druidDataSource; } }问题现象启动项目时发现Bean(shardingDataSource)所对应的 DruidDataSource 初始化时间特别长但Bean(name logAnalysisDataSource)所对应的 DruidDataSource 初始化却很快[2026-02-07 17:47:32.417] [INFO ] [com.zaxxer.hikari.HikariDataSource] [80] - [HikariPool-1 - Starting...] [2026-02-07 17:47:32.739] [INFO ] [com.zaxxer.hikari.HikariDataSource] [82] - [HikariPool-1 - Start completed.] [2026-02-07 17:50:22.107] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-1} inited] [2026-02-07 17:50:34.454] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-2} inited] [2026-02-07 17:50:35.840] [INFO ] [com.xxx.WebApplication] [61] - [Started WebApplication in 188.327 seconds (JVM running for 189.054)]日志中的 HikariDataSource 是 ShardingSphere JDBC 用于操作元数据的内部连接池其初始化完成至 DruidDataSource#init 执行前的耗时可忽略不计启动日志中{dataSource-1}对应Bean(shardingDataSource){dataSource-2}对应Bean(name logAnalysisDataSource)从日志可以看出Bean(shardingDataSource)这个 DruidDataSource 对象的初始化时间为 2 分 50 秒而Bean(name logAnalysisDataSource)这个 DruidDataSource 对象的初始化时间为 12 秒而两者唯一的区别在于底层 JDBC 驱动备注因项目开发环境位于内网且数据库部署于不同地域网络延迟较高数据库连接池初始化耗时 12 秒属正常范围跟踪 Druid 源码发现耗时主要集中在createPhysicalConnection()方法执行过程中该方法负责建立底层物理数据库连接public class DruidDataSource extends DruidAbstractDataSource implements DruidDataSourceMBean, ManagedDataSource, Referenceable, Closeable, Cloneable, ConnectionPoolDataSource, MBeanRegistration { public void init() throws SQLException { try { if (createScheduler ! null asyncInit) { for (int i 0; i initialSize; i) { submitCreateTask(true); } } else if (!asyncInit) { // init connections while (poolingCount initialSize) { try { // 慢在这里 PhysicalConnectionInfo pyConnectInfo createPhysicalConnection(); DruidConnectionHolder holder new DruidConnectionHolder(this, pyConnectInfo); connections[poolingCount] holder; } catch (SQLException ex) { } } } } finally { inited true; lock.unlock(); if (init LOG.isInfoEnabled()) { String msg {dataSource- this.getID(); if (this.name ! null !this.name.isEmpty()) { msg ,; msg this.name; } msg } inited; // 打印日志 LOG.info(msg); } } } }继续跟踪源码最终定位到问题源于 MySQL 驱动在创建连接时调用InetSocketAddress.getHostName()进行反向 DNS 解析耗时显著导致连接初始化缓慢完整的链路DruidAbstractDataSource#createPhysicalConnection ... com.mysql.cj.jdbc.ConnectionImpl#getInstance(HostInfo hostInfo)ConnectionImpl构造方法package com.mysql.cj.jdbc; public class ConnectionImpl implements JdbcConnection, SessionEventListener, Serializable { public ConnectionImpl(HostInfo hostInfo) throws SQLException { try { SocketAddress socketAddress this.session.getRemoteSocketAddress(); if (InetSocketAddress.class.isInstance(socketAddress)) { InetSocketAddress inetSocketAddress (InetSocketAddress) socketAddress; // 关键 this.connectionSpan.setAttribute( TelemetryAttribute.NETWORK_PEER_ADDRESS, // 获取 hostname 字段值 inetSocketAddress.getHostName() ); } } } }package java.net; public class InetSocketAddress extends SocketAddress { private final transient InetSocketAddressHolder holder; // Private implementation class pointed to by all public methods. private static class InetSocketAddressHolder { // The hostname of the Socket Address private String hostname; // The IP address of the Socket Address private InetAddress addr; // The port number of the Socket Address private int port; private InetSocketAddressHolder(String hostname, InetAddress addr, int port) { this.hostname hostname; this.addr addr; this.port port; } private int getPort() { return port; } private InetAddress getAddress() { return addr; } private String getHostName() { if (hostname ! null) return hostname; if (addr ! null) // ⚠️ 触发反向 DNS 解析内网无 DNS 服务 → 阻塞超时 return addr.getHostName(); return null; } } /** * Gets the {code hostname}. * Note: This method may trigger a name service reverse lookup if the * address was created with a literal IP address. * * return the hostname part of the address. */ public final String getHostName() { return holder.getHostName(); } }在网上搜了下有如下的文章片段# 解决 Linux 上 Java 获取 hostname 很慢的问题 在 Linux 环境中运行 Java 应用时有时会遇到 InetAddress.getLocalHost().getHostName() 方法执行缓慢的问题严重影响应用启动速度 ## 问题原因 Java 在调用 getHostName() 时会尝试对本机 IP 地址进行**反向 DNS 解析PTR 查询**以获取主机名若 DNS 服务器不可达、无 PTR 记录或网络延迟高该操作将长时间阻塞 ## 常见场景 - Docker / K8S 容器中未配置 DNS - 内部网络无反向解析支持 - 使用纯 IP 地址连接数据库如 MySQL真相大白我的项目开发环境位于公司内网完全无法访问外网更无外部 DNS 服务支持以下为尝试 ping 外网的输出结果$ ping www.baidu.com Ping 请求找不到主机 www.baidu.com。请检查该名称然后重试。那怎么解释Bean(name logAnalysisDataSource)这个 DruidDataSource 对象的初始化时间仅 12 秒呢这是因为它使用的是jdbc:oceanbase协议与oceanbase-client驱动这个驱动在连接建立过程中不会调用InetSocketAddress.getHostName()方法没看源码仅为猜测但八九不离十如何解决这个问题呢有如下两种方法网上说添加几个 JVM 参数就能解决实测无效上述问题在 SpringBoot 3 Druid 启动慢排查SpringBoot 启动慢、服务偶发接口慢查询MySQL Connector-j 9.0.0 版本问题getHostName() 请求慢 这篇文章中也提到了解决办法一修改 hosts 文件修改 hosts 文件添加域名映射10.xxx.xxx.146 www.define.com从启动日志可以看出问题完美解决[2026-02-07 18:44:04.258] [INFO ] [com.zaxxer.hikari.HikariDataSource] [80] - [HikariPool-1 - Starting...] [2026-02-07 18:44:04.582] [INFO ] [com.zaxxer.hikari.HikariDataSource] [82] - [HikariPool-1 - Start completed.] [2026-02-07 18:44:09.426] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-1} inited] [2026-02-07 18:44:22.180] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-2} inited] [2026-02-07 18:44:23.552] [INFO ] [com.xxx.WebApplication] [61] - [Started WebApplication in 24.191 seconds (JVM running for 24.92)]原理因InetAddress.getHostName()在本地 hosts 有映射时会跳过网络 DNS 查询从而避免阻塞解决办法二降低 MySQL 驱动版本降低至 8.0.33 版本实测有效dependency groupIdcom.mysql/groupId artifactIdmysql-connector-j/artifactId version8.0.33/version /dependency从启动日志可以看出问题完美解决[2026-02-07 18:51:19.582] [INFO ] [com.zaxxer.hikari.HikariDataSource] [80] - [HikariPool-1 - Starting...] [2026-02-07 18:51:19.899] [INFO ] [com.zaxxer.hikari.HikariDataSource] [82] - [HikariPool-1 - Start completed.] [2026-02-07 18:51:24.718] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-1} inited] [2026-02-07 18:51:37.035] [INFO ] [com.alibaba.druid.pool.DruidDataSource] [1007] - [{dataSource-2} inited] [2026-02-07 18:51:38.433] [INFO ] [com.xxx.WebApplication] [61] - [Started WebApplication in 23.6 seconds (JVM running for 24.33)]翻看 8.0.33 中 ConnectionImpl 的源码不会调用InetSocketAddress.getHostName()方法