一个连接池初始化失败时所有连接池初始化失败答案

【问题标题】：All connection pools fail to initialize when one connection pool fails to initialize一个连接池初始化失败时所有连接池初始化失败
【发布时间】：2018-04-25 02:46:28
【问题描述】：

这是一个错误吗？

我将 Playframework 2.6.6 与 scala 2.12.3 一起使用。我在 application.conf 中定义了 3 个数据库（hikaricp 连接池的设置遍布地图，因为我对它们进行了实验）：

db {
  mentions {
    driver="org.postgresql.Driver"
    url="jdbc:postgresql://localhost:5432/mentions"
    password="***"
    username="play"
    hikaricp {
      maximumPoolSize = 2
      minimumIdle=2
    }

  }

  postgres {
    driver="org.postgresql.Driver"
    url="jdbc:postgresql://localhost:5432/postgres"
    password="***"
    username="postgres"
    hikaricp {
      maximumPoolSize = 9
      minimumIdle=9
    }
  }

  sqlserver {
    driver="net.sourceforge.jtds.jdbc.Driver"
    url="jdbc:jtds:sqlserver://10.211.55.5:1433/db"
    username="sa"
    password="***"
    hikaricp {
      maximumPoolSize=4
      minimumIdle=4
      //connectionTestQuery="select 1"
    }
  }

}

使用此配置，Hikaricp 连接池无法初始化 sql server 连接池，实际上其他两个连接池都没有初始化。 sql server连接错误的修复方法是设置connectionTestQuery。这不是这篇文章的重点。我不明白为什么当这个连接失败时其他两个连接会失败。在我看来，其他两个连接池应该仍然有效。

以下是来自控制台的错误消息：

[info] application - Creating Pool for datasource 'sqlserver'
[error] c.z.h.p.PoolBase - HikariPool-1 - Failed to execute isValid() for connection, configure connection test query (null).
[info] application - Creating Pool for datasource 'sqlserver'
[error] c.z.h.p.PoolBase - HikariPool-2 - Failed to execute isValid() for connection, configure connection test query (null).
[info] application - Creating Pool for datasource 'sqlserver'
[error] c.z.h.p.PoolBase - HikariPool-3 - Failed to execute isValid() for connection, configure connection test query (null).
[error] application - 

! @761fipg95 - Internal server error, for (GET) [/] ->

play.api.UnexpectedException: Unexpected exception[CreationException: Unable to create injector, see the following errors:

1) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=sqlserver)) to ProviderTarget(play.api.db.NamedDatabaseProvider@65c05a8b)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

2) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=mentions)) to ProviderTarget(play.api.db.NamedDatabaseProvider@700c1d35)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

3) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=postgres)) to ProviderTarget(play.api.db.NamedDatabaseProvider@1f4f0047)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

3 errors]
    at play.core.server.DevServerStart$$anon$1.reload(DevServerStart.scala:186)
    at play.core.server.DevServerStart$$anon$1.get(DevServerStart.scala:124)
    at play.core.server.AkkaHttpServer.modelConversion(AkkaHttpServer.scala:183)
    at play.core.server.AkkaHttpServer.handleRequest(AkkaHttpServer.scala:189)
    at play.core.server.AkkaHttpServer.$anonfun$createServerBinding$3(AkkaHttpServer.scala:106)
    at akka.stream.impl.fusing.MapAsync$$anon$23.onPush(Ops.scala:1172)
    at akka.stream.impl.fusing.GraphInterpreter.processPush(GraphInterpreter.scala:499)
    at akka.stream.impl.fusing.GraphInterpreter.processEvent(GraphInterpreter.scala:462)
    at akka.stream.impl.fusing.GraphInterpreter.execute(GraphInterpreter.scala:368)
    at akka.stream.impl.fusing.GraphInterpreterShell.runBatch(ActorGraphInterpreter.scala:571)
Caused by: com.google.inject.CreationException: Unable to create injector, see the following errors:

1) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=sqlserver)) to ProviderTarget(play.api.db.NamedDatabaseProvider@65c05a8b)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

2) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=mentions)) to ProviderTarget(play.api.db.NamedDatabaseProvider@700c1d35)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

3) Error injecting method, java.lang.AbstractMethodError
  at com.google.inject.util.Providers$GuicifiedProviderWithDependencies.initialize(Providers.java:149)
  at play.api.db.DBModule$$anonfun$$lessinit$greater$1.$anonfun$new$1(DBModule.scala:25):
Binding(interface play.api.db.Database qualified with QualifierInstance(@play.db.NamedDatabase(value=postgres)) to ProviderTarget(play.api.db.NamedDatabaseProvider@1f4f0047)) (via modules: com.google.inject.util.Modules$OverrideModule -> play.api.inject.guice.GuiceableModuleConversions$$anon$1)

3 errors
    at com.google.inject.internal.Errors.throwCreationExceptionIfErrorsExist(Errors.java:470)
    at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:176)
    at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:110)
    at com.google.inject.Guice.createInjector(Guice.java:99)
    at com.google.inject.Guice.createInjector(Guice.java:84)
    at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:185)
    at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:137)
    at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
    at play.core.server.DevServerStart$$anon$1.$anonfun$reload$3(DevServerStart.scala:174)
    at play.utils.Threads$.withContextClassLoader(Threads.scala:21)
Caused by: java.lang.AbstractMethodError: null
    at net.sourceforge.jtds.jdbc.JtdsConnection.isValid(JtdsConnection.java:2833)
    at com.zaxxer.hikari.pool.PoolBase.checkDriverSupport(PoolBase.java:456)
    at com.zaxxer.hikari.pool.PoolBase.setupConnection(PoolBase.java:423)
    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:381)
    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:205)
    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:448)
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:519)
    at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:113)
    at com.zaxxer.hikari.HikariDataSource.<init>(HikariDataSource.java:72)
    at play.api.db.HikariCPConnectionPool.$anonfun$create$1(HikariCPModule.scala:51)

更新：我仍然认为在架构上，如果一个连接池不起作用，其他连接池不应该受到影响。今天我关闭了运行 sql server 的 windows vm，我只运行了我的 postgresql 服务器。我测试的页面只连接到 postgresql dbs，它仍然失败，因为 sql server 连接池不起作用。这次它失败并出现配置错误 java.sql.SQLException - Login Timed out。

【问题讨论】：

标签： scala jdbc playframework

【解决方案1】：

在 2.6.6 和 2.6.7 中进行了一些调试后，我发现了以下内容：

java.lang.AbstractMethodError 继承 java.lang.IncompatibleClassChangeError 继承 java.lang.LinkageError。 java.lang.LinkageError 根据 NonFatal 对象被认为是致命的：

object NonFatal {
   /**
    * Returns true if the provided `Throwable` is to be considered non-fatal, or false if it is to be considered fatal
    */
   def apply(t: Throwable): Boolean = t match {
     // VirtualMachineError includes OutOfMemoryError and other fatal errors
     case _: VirtualMachineError | _: ThreadDeath | _: InterruptedException | _: LinkageError | _: ControlThrowable => false
     case _ => true
   }
  /**
   * Returns Some(t) if NonFatal(t) == true, otherwise None
   */
  def unapply(t: Throwable): Option[Throwable] = if (apply(t)) Some(t) else None
}

因此，遍布代码的 Try 调用不会捕获此异常。

异常最终由 guice 层处理。该调用返回到 guice Initializer.injectAll 方法，该方法（在其他对象中）为 application.conf 文件中配置的每个数据库连接注入 NamedDatabaseProvider 对象（与 NamedDatabaseProvider 的绑定在 DBModule 中连接）。 NamedDatabaseProvider 对象依赖于 DBApi，其每次初始化都会由于被认为是致命的 AbstractMethodError 异常而失败。

最终问题是多种情况的组合：1. Hikaricp 代码中抛出的异常是致命的，2. DBApi 代码想要初始化所有连接池并且它不处理致命错误。

我不认为这是一个错误。也许 Hickaricp 家伙可能会抛出 UnsupportedOperationException 或 similar。

对于其他感兴趣的人，我发现了这个：https://github.com/njlg/playdb。

【讨论】：