Develop Reference

How to resolve unable to obtain isolated JDBC connection?

I changed hibernate timeout settings as well as idle time but it not working
My hibernate properties are
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.timeout">300000</property>
<property name="hibernate.c3p0.max_statements">50</property>
<property name="hibernate.c3p0.idle_test_period">300000</property>
And, I'm getting following exception :
Exception in thread "main" org.hibernate.exception.JDBCConnectionException: unable to obtain isolated JDBC connection
at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:115)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcIsolationDelegate.delegateWork(JdbcIsolationDelegate.java:103)
at org.hibernate.id.enhanced.TableGenerator$1.getNextValue(TableGenerator.java:530)
at org.hibernate.id.enhanced.NoopOptimizer.generate(NoopOptimizer.java:40)
at org.hibernate.id.enhanced.TableGenerator.generate(TableGenerator.java:526)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:105)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:682)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:674)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:669)
at com.ihealthmantra.upload.com.ihealthmantra.customer.upload.service.SellerUploadImpl.lambda$4(SellerUploadImpl.java:801)
at java.util.ArrayList.forEach(Unknown Source)
at com.ihealthmantra.upload.com.ihealthmantra.customer.upload.service.SellerUploadImpl.createTimeSlotUploadedSeller(SellerUploadImpl.java:738)
at com.ihealthmantra.upload.com.ihealthmantra.customer.upload.service.SellerUploadImpl.populateSlot(SellerUploadImpl.java:1146)
at com.ihealthmantra.upload.App.main(App.java:81)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 820,677 milliseconds ago. The last packet sent successfully to the server was 820,679 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3746)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2509)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2480)
at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:4811)
at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection.java:912)
at org.hibernate.c3p0.internal.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:78)
at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:386)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcIsolationDelegate.delegateWork(JdbcIsolationDelegate.java:48)
... 17 more
Caused by: java.net.SocketException: Connection reset by peer: socket write error
It was working fine earlier, but as data grown recently, it started throwing above exception.

... the server was 820,679 milliseconds ago. is longer than the server
configured value of 'wait_timeout'...
It seems like connection to database server is taking longer time than the value set for timeout. And it was mentioned in your exception as well.
To resolved this issue, either you can increase timeout value or pass autoReconnect=true with your JDBC string (as mentioned in your exception)
To change wait_timeout value in MySQL, you could refer existing post.
MySQL wait_timeout Variable - GLOBAL vs SESSION
OR
Append autoReconnect=true to your JDBC url string
jdbc:mysql://localhost:3306/exodb?autoReconnect=true

Start Java/Play2.5 REST API without DB

I would like to start my Java/Play! Service even though the Database is not yet reachable. So far, if the database is not available the service stops. Is it possible in Play to try and reconnect every second or so without completely stopping the service and reconnecting to db as soon as connection is available.
Our application.conf currently looks like this:
play.evolutions.enabled=false
//play.db.pool=bonecp
db {
default.driver=org.postgresql.Driver
default.url="jdbc:postgresql://postgresdb.postgres:5432/postcode"
default.username="<username>"
default.password="<strong-password>"
}
play.db {
config = "db"
prototype.hikaricp = {
connectionTimeout = 250 milliseconds
initializationFailFast = false
readOnly = true
}
}
ebean.default = ["models.*"]
Currently I get the following logs:
2017-05-15 13:26:54.525 [error] postcode-play: Connection error:
org.postgresql.util.PSQLException: FATAL: remaining connection slots are reserved for non-replication superuser connections
Ort: Datei: postinit.c, Routine: InitPostgres, Zeile: 779.
Server SQLState: 53300
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2412)
at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2538)
at org.postgresql.core.v3.QueryExecutorImpl.<init>(QueryExecutorImpl.java:122)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:227)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
2017-05-15 13:26:54.626 [error] postcode-play: Connection error:
org.postgresql.util.PSQLException: FATAL: remaining connection slots are reserved for non-replication superuser connections
Ort: Datei: postinit.c, Routine: InitPostgres, Zeile: 779.
Server SQLState: 53300
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2412)
at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2538)
at org.postgresql.core.v3.QueryExecutorImpl.<init>(QueryExecutorImpl.java:122)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:227)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
.
.
.
Indicating that the server does not stop altogether but tries to connect to db multiple times which is as desired. But if the database becomes available the following logs are written:
2017-05-15 14:08:43.748 [error] postcode-play:
! #7430ed7gf - Internal server error, for (GET) [/?postcode=88682&country=DE] ->
play.api.Configuration$$anon$1: Configuration error[Cannot connect to database [default]]
at play.api.Configuration$.configError(Configuration.scala:155)
at play.api.Configuration.reportError(Configuration.scala:808)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:48)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:42)
at scala.collection.immutable.List.foreach(List.scala:392)
at play.api.db.DefaultDBApi.connect(DefaultDBApi.scala:42)
at play.api.db.DBApiProvider.get$lzycompute(DBModule.scala:72)
at play.api.db.DBApiProvider.get(DBModule.scala:62)
at play.api.db.DBApiProvider.get(DBModule.scala:58)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:81)
Caused by: java.sql.SQLTransientConnectionException: HikariPool-4 - Connection is not available, request timed out after 5001ms.
at com.zaxxer.hikari.pool.HikariPool.createTimeoutException(HikariPool.java:548)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:186)
at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:145)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:83)
at play.api.db.DefaultDatabase.getConnection(Databases.scala:142)
at play.api.db.DefaultDatabase.getConnection(Databases.scala:138)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:44)
at play.api.db.DefaultDBApi$$anonfun$connect$1.apply(DefaultDBApi.scala:42)
at scala.collection.immutable.List.foreach(List.scala:392)
at play.api.db.DefaultDBApi.connect(DefaultDBApi.scala:42)
Caused by: org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:265)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194)
at org.postgresql.Driver.makeConnection(Driver.java:431)
at org.postgresql.Driver.connect(Driver.java:247)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:95)
at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:101)
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:341)
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:193)
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:430)
Caused by: java.net.ConnectException: Verbindungsaufbau abgelehnt (Connection refused)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.postgresql.core.PGStream.<init>(PGStream.java:62)
at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:144)
at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:194
)
The server cannot reach out to the database even though it is available now. If I restart the server the database will be found and can be worked with, but the database lways has to be there on startup. How can I fix that, so that the app can be started independently of the database?
If the database becomes unavailable after the application has started it is no problem after the db becomes available again. it is automatically reconnected.
Any help is greatly apreciated!

It seems like you are leaving some connections open to Postgres. These connections must be closed or else Postgres will hit its max_connections limit.
You could increase max_connections but it's not recommended as performance of Postgres will degrade if it's set too high. Also, as you are using HikariCP it wouldn't be a bad idea to take a look at the HikariCP docs, in particular the idleTimeout and the minimumIdle config variables should help you.
If the above doesn't work then you must confirm exactly how many connections are being made to Postgres. Maybe even check the number of sessions you personally are making to Postgres via SSH or through other apps, not just the number of Play Framework connections.

Hibernate CreateNativeQuery does not close the connection when the exception arises

I face one issue related to the hibernate CreateNativeQuery.
I have executed the query using the createNativeQuery and return the resultList. If the execution of query fails due to the incorrect query or the reasons, the exception is raised and the connection which is used by the entity manager is not closed. Why the connection is not closed message arrived?
If I use the createQuery method I had faced only the exception and connection is closed properly by the entity manager.
What's the reason behind this???
My code is
return em.createNativeQuery(queryToExecute).getResultList();
Why is the connection not closed if I use the createNativeQuery method?
Log Details
2015-03-13 11:21:40,504 WARN [org.jboss.jca.adapters.jdbc.WrappedConnection] Closing a statement you left open, please do your own housekeeping: java.lang.Throwable: STACKTRACE
at org.jboss.jca.adapters.jdbc.WrappedConnection.registerStatement(WrappedConnection.java:1672) at org.jboss.jca.adapters.jdbc.WrappedStatement.<init>(WrappedStatement.java:105)
at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.<init>(WrappedPreparedStatement.java:69)
at org.jboss.jca.adapters.jdbc.jdk6.WrappedPreparedStatementJDK6.<init>(WrappedPreparedStatementJDK6.java:52)
at org.jboss.jca.adapters.jdbc.jdk6.WrappedConnectionJDK6.wrapPreparedStatement(WrappedConnectionJDK6.java:79)
at org.jboss.jca.adapters.jdbc.WrappedConnection.prepareStatement(WrappedConnection.java:404)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:161)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:182)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:159)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1854)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1831)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1811)
at org.hibernate.loader.Loader.doQuery(Loader.java:899)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341)
at org.hibernate.loader.Loader.doList(Loader.java:2516)
at org.hibernate.loader.Loader.doList(Loader.java:2502)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2332)
at org.hibernate.loader.Loader.list(Loader.java:2327)
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338)
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:1826)
at org.hibernate.internal.AbstractSessionImpl.list(AbstractSessionImpl.java:231)
at org.hibernate.internal.SQLQueryImpl.list(SQLQueryImpl.java:157)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:264)
2015-03-13 11:21:40,506 INFO [org.jboss.jca.core.api.connectionmanager.ccm.CachedConnectionManager] IJ000100: Closing a connection for you. Please close them yourself: org.jboss.jca.adapters.jdbc.jdk6.WrappedConnectionJDK6#7bc7c07d: java.lang.Throwable: STACKTRACE
at org.jboss.jca.core.connectionmanager.ccm.CachedConnectionManagerImpl.registerConnection(CachedConnectionManagerImpl.java:269)
at org.jboss.jca.core.connectionmanager.AbstractConnectionManager.allocateConnection(AbstractConnectionManager.java:495)
at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:139)
at org.hibernate.ejb.connection.InjectedDataSourceConnectionProvider.getConnection(InjectedDataSourceConnectionProvider.java:70)
at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:292)
at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:214)
at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:157)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.connection(StatementPreparerImpl.java:56)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$5.doPrepare(StatementPreparerImpl.java:161)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:182)
at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:159)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1854)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1831)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1811)
Thanks in advance.

MySQL connection reset in java

I have a java code that generate and fill tables to MySQL database.
The method is to create a connection to generate a table and then close that connection afterward.
Then create new connection to fill the table and so on.
I have about 14000 table to generate. The problem is that after generating about 800 tables I got this message and I have to restart mysql again.
Is there a cap to the number of connection I could create? is there anyway to increase it? Any Ideas?
Thanks
java.sql.SQLException: Communication link failure: java.net.SocketException, underlying cause: Connection reset
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: Connection reset
STACKTRACE:
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:189)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:1449)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1826)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1803)
at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:2353)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:750)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:1627)
at com.mysql.jdbc.Connection.<init>(Connection.java:427)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:395)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at db.DbConnection.establishConnection(DbConnection.java:21)
at db.DbActivities.addToDocSent(DbActivities.java:125)
at db.DbGeneration.main(DbGeneration.java:58)
** END NESTED EXCEPTION **

dbunit - SQL exception

I want to extract my database to FlatXmlDataSet. I use this tutorial:
http://www.dbunit.org/faq.html#extract
my code looks:
Class driverClass = Class.forName("oracle.jdbc.driver.OracleDriver");
Connection jdbcConnection = DriverManager.getConnection(
"jdbc:oracle:thin: <my parametres>", "<user>", "<password>");
IDatabaseConnection connection = new DatabaseConnection(jdbcConnection);
// full database export
IDataSet fullDataSet = connection.createDataSet();
FlatXmlDataSet.write(fullDataSet, new FileOutputStream("full.xml"));
and I have error:
Exception in thread "main" org.dbunit.dataset.DataSetException:java.sql.SQLSyntaxErrorException:
ORA-00942: table or view does not exist
at org.dbunit.database.DatabaseDataSet.getTable(DatabaseDataSet.java:316)
at org.dbunit.database.DatabaseTableIterator.getTable(DatabaseTableIterator.java:89)
at org.dbunit.dataset.stream.DataSetProducerAdapter.produce(DataSetProducerAdapter.java:83)
at org.dbunit.dataset.xml.FlatXmlWriter.write(FlatXmlWriter.java:124)
at org.dbunit.dataset.xml.FlatXmlDataSet.write(FlatXmlDataSet.java:341)
at db.main(db.java:26)
Caused by: java.sql.SQLSyntaxErrorException: ORA-00942: table or view does not exist
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:447)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:951)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:513)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:227)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:195)
at oracle.jdbc.driver.T4CStatement.executeForDescribe(T4CStatement.java:876)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1175)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1296)
at oracle.jdbc.driver.OracleStatement.executeQuery(OracleStatement.java:1498)
at oracle.jdbc.driver.OracleStatementWrapper.executeQuery(OracleStatementWrapper.java:406)
at org.dbunit.database.AbstractResultSetTable.<init>(AbstractResultSetTable.java:110)
at org.dbunit.database.ForwardOnlyResultSetTable.<init>(ForwardOnlyResultSetTable.java:59)
at org.dbunit.database.CachedResultSetTableFactory.createTable(CachedResultSetTableFactory.java:60)
at org.dbunit.database.DatabaseDataSet.getTable(DatabaseDataSet.java:312)
... 5 more
I use:
-eclipse
-dbunit 2.4.5
-slf4j 1.5.8
-maven 3.04
Thanks for any help

First of all, check if your connection parameters are correctly spelled, the necessary permissions are set and that the tables from your database really exist. You can then take a look at this similar post java.sql.SQLSyntaxErrorException: ORA-00942.