Good idea to use DBCP if the built-in connection pool is not enough. I
am also using DBCP DataSource which is definitely much more
configurable than the default Cayenne one. Since (a) I am using latest
3.0 builds, and (b) the DataSource is abstracted via JNDI, I haven't
seen the crashes described below. If you have stack traces, please
open a Jira.
Andrus
On Mar 26, 2008, at 3:00 PM, Robert Zeigler wrote:
I've seen the same issue periodically.
Basically, it seems to have something to do with the connection pool
never being emptied, so you wind up with a closed connection.
And yes, I've tried autoReconnect=true,and several related variants.
I finally switched to using DBCP, which lets you specify a "test"
query to ensure that the connection is still valid, as well as a
host of other options.
I haven't seen the exception since. One downside to switching is
that at least the 2.x modeler chokes on trying to load the project
when using the DBCP connection factory.
Something about the auto-adapter detection failing.
Cheers,
Robert
On Mar 26, 2008, at 3/264:51 AM , Alexander Lamb (dev) wrote:
Yes, we did add this parameter but we still can reproduce the bug
locally (on the desktop using Jetty).
But it does it only on one application which has something
"special": it has two models that we merge when starting the app.
On another app also in version 3 but with only one model, it works.
To test, we simply kill MySql while the app is running, then
restart MySql. The reconnect works with the app with one model and
fails partially with the app with the merged models. Once the
exception has been raised, the app continues fine (and so finally
reconnects correctly). There is just no way of knowing where the
exception will be raised (we tried catching an exception at one
place but then the exception appeared at some other place).
Alex
Le 26 mars 08 à 10:27, Andrus Adamchik a écrit :
Are you using "autoReconnect=true" parameter in the MySQL
connection URL?
Thanks,
Andrus
On Mar 26, 2008, at 10:44 AM, Alexander Lamb wrote:
Hello List,
We have an application, deployed successfully with Tapestry
5.0.11 and Cayenne 3.0M3 on Tomcat 6 with MySQL 5.0.
Everything is fine until the point where a long period of
inactivity has passed and (we suppose) all the DataContexts are
garbage collected (we create one DataContext per user session).
The first user who logs in will generate an error on (again, what
we suppose) is a problem reconnecting to MySQL.
To avoid the problem, we "ping" the app to keep it alive... We
also tried to catch the Exception but doing so simply pushes the
problem to another part of the program. The funny thing is that
it is not the first attempt to connect to the database but maybe
the first attempt using either a stored query in the model or raw
SQL.
Here is the kind of message we get:
Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.io.EOFException
STACKTRACE:
java.io.EOFException
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1905)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2351)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2862)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2988)
at com.mysql.jdbc.Connection.setAutoCommit(Connection.java:4913)
at
org
.apache
.cayenne
.conn
.PooledConnectionImpl.getConnection(PooledConnectionImpl.java:129)
at
org
.apache
.cayenne.conn.PoolManager.uncheckConnection(PoolManager.java:383)
at
org
.apache.cayenne.conn.PoolManager.getConnection(PoolManager.java:
367)
at
org
.apache.cayenne.conn.PoolManager.getConnection(PoolManager.java:
344)
at org.apache.cayenne.access.DataNode
$TransactionDataSource.getConnection(DataNode.java:321)
at
org.apache.cayenne.access.DataNode.performQueries(DataNode.java:
209)
at
org
.apache
.cayenne
.access.DataDomainQueryAction.runQuery(DataDomainQueryAction.java:
442)
at org.apache.cayenne.access.DataDomainQueryAction.access
$000(DataDomainQueryAction.java:67)
at org.apache.cayenne.access.DataDomainQueryAction
$2.transform(DataDomainQueryAction.java:415)
at
org
.apache
.cayenne.access.DataDomain.runInTransaction(DataDomain.java:847)
at
org
.apache
.cayenne
.access
.DataDomainQueryAction
.runQueryInTransaction(DataDomainQueryAction.java:412)
at
org
.apache
.cayenne
.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:
119)
at org.apache.cayenne.access.DataDomain.onQuery(DataDomain.java:
740)
at
org
.apache
.cayenne
.util
.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:
296)
at org.apache.cayenne.util.ObjectContextQueryAction
$1.createObject(ObjectContextQueryAction.java:286)
at org.apache.cayenne.cache.MapQueryCache.get(MapQueryCache.java:
74)
at
org
.apache
.cayenne
.util
.ObjectContextQueryAction
.interceptLocalCache(ObjectContextQueryAction.java:258)
at
org
.apache
.cayenne
.util
.ObjectContextQueryAction.execute(ObjectContextQueryAction.java:82)
at
org.apache.cayenne.access.DataContext.onQuery(DataContext.java:
1331)
at
org
.apache.cayenne.access.DataContext.performQuery(DataContext.java:
1320)
at
ch
.rodano
.studies
.services
.StudySession
.getRunningTotalPatientsByMonthForRegistryCenters
(StudySession.java:466)
etc...
Thanks for any idea!
Alex
--
Alexander Lamb
Founding Associate
RODANOTECH Sàrl
4 ch. de la Tour de Champel
1206 Geneva
Switzerland
Tel: 022 347 77 37
Fax: 022 347 77 38
http://www.rodanotech.ch
