Java 为什么冬眠一段时间后会变慢？

在执行相同的查询（只读）时，hibernate会减慢速度的原因是什么

日志：

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从日志中可以看到，执行时间增加了十倍，可以配置Hibernate c3p0以提高效率。 连接池有利于提高性能，因为它可以防止Java应用程序在每次与数据库交互时创建连接，并将打开和关闭连接的成本降至最低

请尝试此链接以在应用程序中配置hibernate c3p0：

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是不是数据库更忙了？数据库不忙了。之后，它会减速并保持这种状态（前10次执行时间约为100ms，然后每隔500ms）。请求发送的速度有多快？可能是数据库阻止了快速的后续请求。spring应用程序似乎不太可能让它慢下来。在测试运行的同时，尝试从同一IP手动查询数据库，看看它是否慢。我这样做了，执行时间大约为30毫秒，它甚至不会增加一次到30毫秒以上，可能就是这样，

   368588 nanoseconds spent acquiring 1 JDBC connections;
   0 nanoseconds spent releasing 0 JDBC connections;
   158339 nanoseconds spent preparing 3 JDBC statements;
   33855736 nanoseconds spent executing 3 JDBC statements;
   0 nanoseconds spent executing 0 JDBC batches;
   0 nanoseconds spent performing 0 L2C puts;
   0 nanoseconds spent performing 0 L2C hits;
   0 nanoseconds spent performing 0 L2C misses;
   0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
   9437 nanoseconds spent executing 3 partial-flushes (flushing a total of 0 entities and 0 collections)
}
2020-03-24 09:02:54.488  INFO 12024 --- [io-8064-exec-10] i.StatisticalLoggingSessionEventListener : Session Metrics {
   44640 nanoseconds spent acquiring 1 JDBC connections;
   0 nanoseconds spent releasing 0 JDBC connections;
   134337 nanoseconds spent preparing 3 JDBC statements;
   33256438 nanoseconds spent executing 3 JDBC statements;
   0 nanoseconds spent executing 0 JDBC batches;
   0 nanoseconds spent performing 0 L2C puts;
   0 nanoseconds spent performing 0 L2C hits;
   0 nanoseconds spent performing 0 L2C misses;
   0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
   9156 nanoseconds spent executing 3 partial-flushes (flushing a total of 0 entities and 0 collections)
}
2020-03-24 09:02:56.143  INFO 12024 --- [nio-8064-exec-1] i.StatisticalLoggingSessionEventListener : Session Metrics {
   47060 nanoseconds spent acquiring 1 JDBC connections;
   0 nanoseconds spent releasing 0 JDBC connections;
   123461 nanoseconds spent preparing 3 JDBC statements;
   468759882 nanoseconds spent executing 3 JDBC statements;
   0 nanoseconds spent executing 0 JDBC batches;
   0 nanoseconds spent performing 0 L2C puts;
   0 nanoseconds spent performing 0 L2C hits;
   0 nanoseconds spent performing 0 L2C misses;
   0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
   9680 nanoseconds spent executing 3 partial-flushes (flushing a total of 0 entities and 0 collections)
}