我正在寻找关于如何配置我的 play 2.0 应用程序以在数据库演变和运行时不使用这么多数据库连接的任何见解。我已经在小组和 IRC 中问过这个问题，但没有运气。
我正在使用带有heroku的cleardb ignite实例（max_user_connections = 10）......
基本上，当我尝试在我的 play 2.0 应用程序上运行数据库演化时，我得到：
! @6a2mjd7kg - Internal server error, for request [GET /] ->
play.api.db.evolutions.InvalidDatabaseRevision: Database 'default' needs evolution! [An SQL script need to be run on your database.]
at play.api.db.evolutions.EvolutionsPlugin$$anonfun$onStart$1.apply(Evolutions.scala:424) ~[play_2.9.1.jar:2.0]
at play.api.db.evolutions.EvolutionsPlugin$$anonfun$onStart$1.apply(Evolutions.scala:410) ~[play_2.9.1.jar:2.0]
at scala.collection.LinearSeqOptimized$class.foreach(LinearSeqOptimized.scala:59) ~[scala-library.jar:0.11.2]
at scala.collection.immutable.List.foreach(List.scala:45) ~[scala-library.jar:0.11.2]
at play.api.db.evolutions.EvolutionsPlugin.onStart(Evolutions.scala:410) ~[play_2.9.1.jar:2.0]
at play.api.Play$$anonfun$start$1.apply(Play.scala:60) ~[play_2.9.1.jar:2.0]
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 10. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 9. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 8. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 7. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 6. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 5. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 4. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 3. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 2. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 1. Exception: null
[error] application -
! Internal server error, for request [GET /@evolutions/apply/default?redirect=http%3A%2F%2Flocalhost%3A9000%2F] ->
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: User '52841e548f150d' has exceeded the 'max_user_connections' resource (current value: 10)
at sun.reflect.GeneratedConstructorAccessor26.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl. java:27) ~[na:1.6.0_29]
at java.lang.reflect.Constructor.newInstance(Constructor.java:513) ~[na:1.6.0_29]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java- 5.1.18.jar:na]
at com.mysql.jdbc.Util.getInstance(Util.java:386) ~[mysql-connector-java-5.1.18.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052) ~[mysql-connector-java-5.1.18.jar:na]
然后我也经常会得到通常的“超过 max_user_connections”，这在不进行进化时也经常发生。
我也可以收到此错误消息：
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: User '52841e548f150d' has exceeded the 'max_user_connections' resource (current value: 10)
at sun.reflect.GeneratedConstructorAccessor19.newInstance(Unknown Source) ~[na:na]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) ~[na:1.6.0_29]
at java.lang.reflect.Constructor.newInstance(Constructor.java:513) ~[na:1.6.0_29]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) ~[mysql-connector-java-5.1.18.jar:na]
at com.mysql.jdbc.Util.getInstance(Util.java:386) ~[mysql-connector-java-5.1.18.jar:na]
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052) ~[mysql-connector-java-5.1.18.jar:na]
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 10. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 9. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 8. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 7. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 6. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 5. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 4. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 3. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 2. Exception: null
[error] c.j.b.h.AbstractConnectionHook - Failed to acquire connection Sleeping for 1000ms and trying again. Attempts left: 1. Exception: null
[error] application -
我的 application.conf 看起来像这样，我尝试了很多变体......
db.default=mysql
db.default.driver=com.mysql.jdbc.Driver
db.default.url="mysql://usr:pass@db_url.com/db_name"
db.default.minSize=1
db.default.maxSize=2
在这一点上，任何指导、建议、链接都会非常有帮助......