Persistence MySQL Errors - or how i am going crazy

i am going crazy … every 5 minutes are there other problems … everything worked fine as long as i had a strategy with “*” for every item …
i deleted all tables in my mysql database, openhab created it after a restart … but the error still occurs.

now i have changed it to “grp_persistence_mysql*” only …

before

    * : strategy = everyChange, restoreOnStartup

now

grp_homebb01_persistence_mysql* : strategy = everyChange, restoreOnStartup

item definition

Number    num_homebb01_tempds03    "Steuerung innen [%.4f °C]"    <temperature>    (grp_charts_temp,grp_charts_tehusw,grp_persistence_mysql)        { mqtt="<[mosquitto:.../...:state:default]" }

rule

rule "rule_num_homebb01_tempds03 updated"
when
    Item num_homebb01_tempds03 received update
then
    dat_homebb01_tempds03_lastupdate.postUpdate(new DateTimeType)

    num_homebb01_tempds03_minimum04.postUpdate((num_homebb01_tempds03.minimumSince(now.minusHours(4), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_maximum04.postUpdate((num_homebb01_tempds03.maximumSince(now.minusHours(4), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_average04.postUpdate((num_homebb01_tempds03.averageSince(now.minusHours(4), "mysql")).toString())

    num_homebb01_tempds03_minimum12.postUpdate((num_homebb01_tempds03.minimumSince(now.minusHours(12), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_maximum12.postUpdate((num_homebb01_tempds03.maximumSince(now.minusHours(12), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_average12.postUpdate((num_homebb01_tempds03.averageSince(now.minusHours(12), "mysql")).toString())

    num_homebb01_tempds03_minimum24.postUpdate((num_homebb01_tempds03.minimumSince(now.minusHours(24), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_maximum24.postUpdate((num_homebb01_tempds03.maximumSince(now.minusHours(24), "mysql").state as DecimalType).toString())
    num_homebb01_tempds03_average24.postUpdate((num_homebb01_tempds03.averageSince(now.minusHours(24), "mysql")).toString())
end

openhab.log

[ERROR] [o.o.c.s.ScriptExecutionThread ] - Error during the execution of rule 'rule_num_homebb01_tempds03 updated'
java.lang.NullPointerException: null
        at org.openhab.core.persistence.extensions.PersistenceExtensions.minimumSince(PersistenceExtensions.java:311) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.invokeOperation(XbaseInterpreter.java:729) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._featureCallOperation(XbaseInterpreter.java:713) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.openhab.model.script.interpreter.ScriptInterpreter.internalFeatureCallDispatch(ScriptInterpreter.java:69) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(XbaseInterpreter.java:549) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(XbaseInterpreter.java:545) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateCastedExpression(XbaseInterpreter.java:375) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor56.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(XbaseInterpreter.java:545) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.evaluateArgumentExpressions(XbaseInterpreter.java:751) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._featureCallOperation(XbaseInterpreter.java:712) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.openhab.model.script.interpreter.ScriptInterpreter.internalFeatureCallDispatch(ScriptInterpreter.java:69) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._evaluateMemberFeatureCall(XbaseInterpreter.java:549) ~[na:na]
        at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source) ~[na:na]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
        at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:291) ~[na:na]
        at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:218) ~[na:na]

and this also occurs

2016-09-04 21:24:01.568 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:24:01.569 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:24:01.571 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Could not store item 'num_homebb01_tempds03' in database with statement 'INSERT INTO Item1 (TIME, VALUE) VALUES(NOW(),?) ON DUPLICATE KEY UPDATE VALUE=?;': No operations allowed after connection closed.
2016-09-04 21:24:01.574 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:24:01.576 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:24:01.579 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Error count exceeded 5. Disconnecting database.
2016-09-04 21:24:01.611 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Error count exceeded 5. Disconnecting database.
2016-09-04 21:25:07.877 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:25:07.891 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:25:07.896 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Could not store item 'num_homebb01_tempds03' in database with statement 'INSERT INTO Item1 (TIME, VALUE) VALUES(NOW(),?) ON DUPLICATE KEY UPDATE VALUE=?;': No operations allowed after connection closed.
2016-09-04 21:25:07.906 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:25:07.934 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:25:07.948 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Connection is not valid!
2016-09-04 21:25:07.957 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Error count exceeded 5. Disconnecting database.
2016-09-04 21:25:07.970 [ERROR] [.p.m.i.MysqlPersistenceService] - mySQL: Error count exceeded 5. Disconnecting database.