内存中 H2 db 的单元测试变得非常慢

Question

我们针对内存数据库运行了大量测试。每个测试都会创建其模式。

到目前为止，我们正在针对 HSQL 数据库运行这些测试，但由于 H2 应该更快，因此我们尝试切换到 H2。

从执行时间来看，H2 实际上要快得多 (10-50%)。但是，当运行大量测试时，H2 似乎会在中间休息，导致整体性能比 HSQLDB (800-900%) 差得多。

有什么想法如何保持完整测试套件的单个测试的良好性能吗？

这些是我们为 H2 尝试过的 URL：

jdbc:h2:mem:testdb
jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1
jdbc:h2:mem:testdb;MVCC=true
jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;MODE=Oracle;MVCC=true

这是我们在 HSQL DB 中使用的 URL：

jdbc:hsqldb:mem:testdb

编辑：

我尝试编写一个可重现的测试用例，但这并不容易，因为我们似乎没有遇到问题当我们只使用简单的jdbc时。经过大约 500 个全部使用 hibernate 的测试后，测试变得缓慢。

我在 VisualVM 中注意到的唯一一件事是，在测试开始变慢的同时，CPU 使用率下降到接近于零，并伴有一些噪音。

编辑2：

JStack输出：

2011-11-21 08:42:34
Full thread dump Java HotSpot(TM) Client VM (16.3-b01 mixed mode):

"ReaderThread" prio=6 tid=0x18e47400 nid=0x318 runnable [0x190ef000]
   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
    - locked <0x099d61c0> (a java.io.InputStreamReader)
    at java.io.InputStreamReader.read(InputStreamReader.java:167)
    at java.io.BufferedReader.fill(BufferedReader.java:136)
    at java.io.BufferedReader.readLine(BufferedReader.java:299)
    - locked <0x099d61c0> (a java.io.InputStreamReader)
    at java.io.BufferedReader.readLine(BufferedReader.java:362)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner$ReaderThread.run(RemoteTestRunner.java:140)

   Locked ownable synchronizers:
    - None

"Low Memory Detector" daemon prio=6 tid=0x0244c400 nid=0x908 runnable [0x00000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
    - None

"CompilerThread0" daemon prio=10 tid=0x02447800 nid=0x10fc waiting on condition [0x00000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
    - None

"Attach Listener" daemon prio=10 tid=0x02446400 nid=0x930 waiting on condition [0x00000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
    - None

"Signal Dispatcher" daemon prio=10 tid=0x02443400 nid=0xf08 runnable [0x00000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
    - None

"Finalizer" daemon prio=8 tid=0x02412400 nid=0x13cc in Object.wait() [0x186bf000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x099d6410> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118)
    - locked <0x099d6410> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

   Locked ownable synchronizers:
    - None

"Reference Handler" daemon prio=10 tid=0x0240d800 nid=0xbe4 in Object.wait() [0x1862f000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x099d6498> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:485)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
    - locked <0x099d6498> (a java.lang.ref.Reference$Lock)

   Locked ownable synchronizers:
    - None

"main" prio=6 tid=0x0011e000 nid=0x1028 in Object.wait() [0x003ce000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x09efc2a0> (a org.h2.engine.Database)
    at org.h2.table.RegularTable.doLock(RegularTable.java:520)
    at org.h2.table.RegularTable.lock(RegularTable.java:434)
    - locked <0x09efc2a0> (a org.h2.engine.Database)
    at org.h2.command.ddl.AlterTableAddConstraint.tryUpdate(AlterTableAddConstraint.java:93)
    at org.h2.command.ddl.AlterTableAddConstraint.update(AlterTableAddConstraint.java:68)
    at org.h2.command.CommandContainer.update(CommandContainer.java:73)
    at org.h2.command.Command.executeUpdate(Command.java:219)
    - locked <0x09efc2a0> (a org.h2.engine.Database)
    at org.h2.jdbc.JdbcStatement.executeUpdateInternal(JdbcStatement.java:125)
    - locked <0x0b69dd50> (a org.h2.engine.Session)
    at org.h2.jdbc.JdbcStatement.executeUpdate(JdbcStatement.java:110)
    at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:421)
    at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:379)
    at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:273)
    at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:219)
    at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:372)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1845)
    at de.xyz.dps.server.core.database.HibernateUtil.createSessionFactory(HibernateUtil.java:55)
    at de.xyz.dps.server.core.database.HibernateUtil.getSessionFactory(HibernateUtil.java:40)
    at de.xyz.dps.server.core.database.TransactionContext.getContext(TransactionContext.java:52)
    at de.xyz.dps.server.core.serviceimpl.AbstractDatabaseService.getSession(AbstractDatabaseService.java:53)
    at de.xyz.dps.server.core.serviceimpl.AbstractDatabaseService.save(AbstractDatabaseService.java:36)
    at de.xyz.dps.server.core.serviceimpl.AbstractDatabaseService.save(AbstractDatabaseService.java:31)
    at de.xyz.dps.server.authentication.serviceimpl.DatabaseUserServiceTest.prepareAndSaveATechnicalSectionTO(DatabaseUserServiceTest.java:328)
    at de.xyz.dps.server.authentication.serviceimpl.DatabaseUserServiceTest.setup(DatabaseUserServiceTest.java:87)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
    at de.xyz.dps.server.core.database.SessionFactoryRule$1.evaluate(SessionFactoryRule.java:90)
    at de.xyz.dps.common.util.ThreadRegistryRule$1.evaluate(ThreadRegistryRule.java:34)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

   Locked ownable synchronizers:
    - None

"VM Thread" prio=10 tid=0x0240a400 nid=0x102c runnable 

"VM Periodic Task Thread" prio=10 tid=0x0245e400 nid=0xdf4 waiting on condition 

JNI global references: 967

似乎测试在创建模式时正在等待一些数据库锁定。

编辑3：

这似乎是多个连接的问题。当我用 jdbc:h2:mem: （未命名私有；一个连接）替换 jdbc:h2:mem:test （一个进程中的多个连接）时，一切都很好（但比 hsql 数据库中慢约 10%）。

编辑4：

好的，我对文件数据库运行了测试，并且可以通过这种方式找到跟踪文件。这里的问题是一样的。 跟踪文件

Answer 1

问题解决了。
800 个测试中，有两个测试没有清理会话并让它们打开。
看来HSQL DB对这个问题的容忍度更高。
总而言之，我们的增速放缓了约 5%。

感谢托马斯·穆勒的支持。