Does anybody have an idea where to look for the cause of the following exception:
org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is org.apache.tomcat.jdbc.pool.PoolExhaustedException: [SimpleAsyncTaskExecutor-240] Timeout: Pool empty. Unable to fetch a connection in 30 seconds, none available[size:100; busy:0; idle:0; lastwait:30000].
What I find really strange is that it says that no connections are available while none are busy.
Everywhere that I look, the same error occurs but the number of busy connections is at least greater than 0.
I don't know whether this matters, but Tomcat version is 8.5.20.
Any idea are welcome!
Related
HikariPool-1 - Connection marked as broken because of SQLSTATE(08S01), ErrorCode(-99999)
java.sql.SQLNonTransientConnectionException: Communication link failure. (Read timed out)
I kept getting this problem, when creating a table with data, which was about 6million records. On ACS, an sql developer, it took around 1½ minute.
I found out that default connection validation (spring.datasource.hikari.validationTimeout) was set to 5000 (5 seconds).
This lead to hikari, not being able to validate the connection, because it was busy for long time.
Solution was setting this property to a high enough number (i set it to 5minutes - 300000)
A JBoss 5.2 application server log was filled with thousands of the following exception:
Caused by: javax.resource.ResourceException: Unable to get managed connection for jdbc_TestDB
at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:441)
at org.jboss.resource.connectionmanager.TxConnectionManager.getManagedConnection(TxConnectionManager.java:424)
at org.jboss.resource.connectionmanager.BaseConnectionManager2.allocateConnection(BaseConnectionManager2.java:496)
at org.jboss.resource.connectionmanager.BaseConnectionManager2$ConnectionManagerProxy.allocateConnection(BaseConnectionManager2.java:941)
at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:96)
... 9 more
Caused by: javax.resource.ResourceException: No ManagedConnections available within configured blocking timeout ( 30000 [ms] )
at org.jboss.resource.connectionmanager.InternalManagedConnectionPool.getConnection(InternalManagedConnectionPool.java:311)
at org.jboss.resource.connectionmanager.JBossManagedConnectionPool$BasePool.getConnection(JBossManagedConnectionPool.java:689)
at org.jboss.resource.connectionmanager.BaseConnectionManager2.getManagedConnection(BaseConnectionManager2.java:404)
... 13 more
I've stripped off the first part of the exception, which is basically our internal JDBC wrapper code which tries to get a DB connection from the pool.
Looking at the Oracle DB side I ran the query:
select resource_name, current_utilization, max_utilization, limit_value
from v$resource_limit
where resource_name in ('sessions', 'processes');
This produced the output:
RESOURCE_NAME CURRENT_UTILIZATION MAX_UTILIZATION LIMIT_VALUE
processes 1387 1500 1500
sessions 1434 1586 2272
Given the fact that that PROCESSES limit of 1500 was reached, would this cause the JBoss exceptions we experienced? I've also been investigating the possibility of connection leaks, but haven't found any evidence of that so far.
What is the recommended course of action here? Is simply increasing the limit a valid solution?
Usually when max_utilization gets the processes value listener will refuse new connections to database. you can see the errors relates to it in alert log. to solve this in database side you should increase the processes parameter.
hmm strange. is it possible, that exception wrapping in JBOSS hides the original error? You should get some sql exception whose text starts with ORA-. Maybe your JDBC wrapper does not handle errors properly.
The recommended actions is to:
check configured size of connection pool against processes sessions Oracle startup paramters.
check Oracles view v$session, especially columns STATUS, LAST_CALL_ET, SQL_ID, PREV_SQL_ID.
translate sql_id(prev_sql_id) into sql_text via v$sql.
if you application has a connection leak, sql_id and pred_sql_id might point you onto a place in your source code, where a connection was used last (i.e. where it was leaked).
I am using hibernate 3 along with spring.My Hibernate configurations are as under :
hibernate.dialect=org.hibernate.dialect.Oracle8iDialect
hibernate.connection.release_mode=on_close
But after starting application, even if only one user accesses it then also I am getting this exception :
ORA-00020: maximum number of processes (550) exceeded
This is stacktrace:
Caused by: java.sql.SQLException: ORA-00020: maximum number of processes (550) exceeded
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:331)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:288)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:743)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:216)
at oracle.jdbc.driver.T4CPreparedStatement.executeForDescribe(T4CPreparedStatement.java:799)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1038)
at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:839)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1133)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3285)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3329)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:76)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1953)
at org.hibernate.loader.Loader.doQuery(Loader.java:802)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274)
at org.hibernate.loader.Loader.loadEntity(Loader.java:2037)
I have kept connection pool time out = 5000. I have also tried to found the cause and got that release mode may affect the mechanism of closing DB resources. But I couldn't find exact solution for that.
Please help..
Thanks in advance..
This is a database error not an application error so you need to go to the database to solve it. 550 processes is a lot more than it sounds so either someone has gone insane or you have a lot of inactive processes running.
The best way to find out is to query the v$session view or Gv$session if you're using a RAC, look at the STATUS column.
Take careful not of where all these sessions are coming from; the OSUSER, TERMINAL and PROGRAM will probably be the most useful. It might almost be worth creating a temporary table with this information - proof and a record afterwards. Then after checking that you're not going to break anything, and with your DBAs if you have any, kill all the inactive sessions simultaneously or one at a time.
That'll remove the error but if it's occurred once it can occur again, so you need to solve it. Either:
You've got a lot of people using the database.
There is an application / program somewhere that is not closing it's
sessions after it's finished.
Someone is connecting in the middle of a loop.
Whichever reason it is you need to track it down and correct it. I'd start with the program or terminal from v$session that had the most number of processes.
I am trying to understand what the "Count" column means in a WebSphere FFDC exception log. IBM told us we have received this error 6835 times. I have not found a good guide which explains what this count shows but from what I have seen it seems to be the number of times that this exception happened since the last JVM restart. The problem is that does not match up with our logs as this error only appears to be thrown 1 time per day with our daily restarts which I can see in the Systemout.log. Also this count doesn't seem to change over a weeks time in the exception logs. Can anyone help?
Index Count Time of last Occurrence Exception SourceId ProbeId
------+------+---------------------------+--------------------------
21 6835 11/19/11 7:00:17:631 UTC java.util.zip.ZipException com.ibm.ws.classloader.ClassLoaderUtils.addDependents 238
This website may be helpful: http://wasdynacache.blogspot.com/2011_07_01_archive.html (Section entitled "First Failure Data Capture for your enterprise application with WebSphere Application Server")
FFDC is capturing the state of the application server and/or the
application when an unexpected error or exception occurs the first
time. All subsequent iterations of the same error/exception are
ignored.
I tried seeing if I could find information for you specifically about count, but all FFDC logs can be formatted differently depending on which application calls it and which formatter the call uses. Good luck.
I get the following error under a certain scenario
When a different thread is populating a lot of users via the bulk upload operation and I was trying to view the list of all users on a different web page. The list query, throws the following timeout error. Is there a way to set this timeout so that I can avoid this timeout error.
Env: h2 (latest), Hibernate 3.3.x
Caused by: org.h2.jdbc.JdbcSQLException: Timeout trying to lock table "USER"; SQL statement:
[50200-144]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:327)
at org.h2.message.DbException.get(DbException.java:167)
at org.h2.message.DbException.get(DbException.java:144)
at org.h2.table.RegularTable.doLock(RegularTable.java:482)
at org.h2.table.RegularTable.lock(RegularTable.java:416)
at org.h2.table.TableFilter.lock(TableFilter.java:139)
at org.h2.command.dml.Select.queryWithoutCache(Select.java:571)
at org.h2.command.dml.Query.query(Query.java:257)
at org.h2.command.dml.Query.query(Query.java:227)
at org.h2.command.CommandContainer.query(CommandContainer.java:78)
at org.h2.command.Command.executeQuery(Command.java:132)
at org.h2.server.TcpServerThread.process(TcpServerThread.java:278)
at org.h2.server.TcpServerThread.run(TcpServerThread.java:137)
at java.lang.Thread.run(Thread.java:619)
at org.h2.engine.SessionRemote.done(SessionRemote.java:543)
at org.h2.command.CommandRemote.executeQuery(CommandRemote.java:152)
at org.h2.jdbc.JdbcPreparedStatement.executeQuery(JdbcPreparedStatement.java:96)
at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:342)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1808)
at org.hibernate.loader.Loader.doQuery(Loader.java:697)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2228)
... 125 more
Yes, you can change the lock timeout. The default is relatively low: 1 second (1000 ms).
In many cases the problem is that another connection has locked the table, and using multi-version concurrency also solves the problem (append ;MVCC=true to the database URL).
EDIT: MVCC=true param is no longer supported, because since h2 1.4.200 it's always true for a MVStore engine, which is a default engine.
I faced quite the same problem and using the parameter "MVCC=true", it solved it. You can find more explanations about this parameter in the H2 documentation here : http://www.h2database.com/html/advanced.html#mvcc
I'd like to suggest that if you are getting this error, then perhaps you should not be using a transaction on your bulk database operation. Consider instead doing a transaction on each individual update: does it make sense to think of an entire bulk import as a transaction? Probably not. If it does, then yes, MVCC=true or a bigger lock timeout is a reasonable solution.
However, I think for most cases, you are seeing this error because you are trying to perform a very long transaction - in other words you are not aware that you are performing a really long transaction. This was certainly the case for myself and I simply took more care on how I was writing records (either using no transactions or using smaller transactions) and the lock timeout issue was resolved.
For those having this issue with integration tests (i.e. server is accessing the h2 db and an integration test is accessing the db before calling the server, to prepare the test), adding a 'commit' to the script executed before the test makes sure that the data are in the database before calling the server (without MVCC=true - which I find is a bit 'weird' if it is not enabled by default).
I had MVCC=true in my connection string but still was getting error above. I had added ;DEFAULT_LOCK_TIMEOUT=10000;LOCK_MODE=0 and problem was solved
I got this issue with the PlayFramework
JPAQueryException occured : Error while executing query from
models.Page where name = ?: Timeout trying to lock table "PAGE"
It ended being an infinite loop of sorts because I had a
#Before
without an unless which caused the function to repeatedly call itself
#Before(unless="getUser")
Working with DBUnit, H2 and Hibernate - same error, MVCC=true helped, but I would still get the error for any tests following deletion of data. What fixed these cases was wrapping the actual deletion code inside a transaction:
Transaction tx = session.beginTransaction();
...delete stuff
tx.commit();
From a 2020 user, see reference
Basically, the reference says:
Sets the lock timeout (in milliseconds) for the current session. The default value for this setting is 1000 (one second).
This command does not commit a transaction, and rollback does not affect it. This setting can be appended to the database URL: jdbc:h2:./test;LOCK_TIMEOUT=10000