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Home » Eclipse Projects » EclipseLink » Connections from Connection Pool closed by database -> EL hangs
Connections from Connection Pool closed by database -> EL hangs [message #496610] Tue, 10 November 2009 16:45
Thomas Haskes is currently offline Thomas Haskes
Messages: 147
Registered: July 2009
Senior Member
Hi all,

I am currently having severe problems using EL on an Oracle Database. I
have a Eclipselink internal Connection Pool configured using the
persistence xml, using 2 Connections for read and write. My problem is
that the database closes the connections from the connection pool after
being idle for a while. The problem is that EL doesn't recognise that
these connections were closed and tries to execute a statement on them,
which results in EL hanging for about 10 minutes. EL that states that
there is a communiation problem and tries to rexecute the query by
querying a "select 1 from dual", which takes 10 minutes again. After
that, EL recognises the connection is gone and creates a new one.

Is there any way to configure the connection pool so that it keeps at
least the configured minimum of connections alive, so that cannot be
closed by the database, or any other workaround or solution for that
problem?

I attach the log output, you can see the described behaviour there. I
crossed out some sensible Information.

Note that El is hanging for 8 minutes the first time and then another 10
minutes after the "select 1 from dual".

Note also that we use EL in a JAVA SE configuration, although this log
messages are comming form a jboss server, we also use our apps on a
standard webserver, so we need to use the EL internal Connection Pool.

TIA

Tom


--------------------------------------ServerLog------------- ----------------------------

009-11-10 16:57:02,717 INFO [STDOUT] [EL Fine]: 2009-11-10
16:57:02.717--ServerSession(24117517)--Connection(5427592)-- Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--select
PCK_IM_WEB_USER.Pruefe_Anmeldung(?) from dual
bind => [[XXXXXX]

----nothing happening--------


2009-11-10 17:05:45,249 INFO [STDOUT] [EL Config]: 2009-11-10
17:05:45.249--ServerSession(24117517)--Connection(5427592)-- Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--disconnect
2009-11-10 17:05:45,249 INFO [STDOUT] [EL Info]: 2009-11-10
17:05:45.249--UnitOfWork(4798266)--Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--Communication failure
detected when attempting to perform read query outside of a transaction.
Attempting to retry query.
2009-11-10 17:05:45,249 INFO [STDOUT] [EL Fine]: 2009-11-10
17:05:45.249--ServerSession(24117517)--Thread(Thread[UIThrea d
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--SELECT 1 FROM DUAL

---nothing happening again--------


2009-11-10 17:14:27,562 INFO [STDOUT] [EL Config]: 2009-11-10
17:14:27.562--ServerSession(24117517)--Connection(29394850)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--connecting(Dat abaseLogin(
platform=>Oracle10Platform
user name=> "XXXXXXX"
datasource URL=> "jdbc:oracle:thin:@XXXXXXXXXXX"
))
2009-11-10 17:14:27,683 INFO [STDOUT] [EL Config]: 2009-11-10
17:14:27.683--ServerSession(24117517)--Connection(17349722)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--Connected:
jdbc:oracle:thin:@XXXXXXXXXXXXXXX
User: XXXXXXXXX
Database: Oracle Version: Oracle Database 10g Enterprise
Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing
options
Driver: Oracle JDBC driver Version: 10.1.0.4.2
2009-11-10 17:14:27,684 INFO [STDOUT] [EL Fine]: 2009-11-10
17:14:27.683--ServerSession(24117517)--Connection(17349722)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--select
PCK_IM_WEB_USER.Pruefe_Anmeldung(?) from dual
bind => [[XXXXXX]
2009-11-10 17:14:27,697 INFO [STDOUT] [EL Fine]: 2009-11-10
17:14:27.697--ServerSession(24117517)--Connection(17349722)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--SELECT TRAN_ID, BNNAME,
KE_PRINT, KE_SELECT, KE_DELETE, KE_INSERT, KE_UPDATE, KE_ENTER_QUERY
FROM MV_SBNTA WHERE (BNNAME = ?)
bind => [XXXX]
2009-11-10 17:14:27,700 INFO [STDOUT] [EL Fine]: 2009-11-10
17:14:27.7--ServerSession(24117517)--Connection(17349722)--T hread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--SELECT BNNAME, TELEFAX,
LBNR, IADRNR, TITEL, NAME, KE_GESCHLECHT, TELEFON, KE_GESPERRT, VNAME,
ABTEILUNG, ANREDE FROM MV_BENUTZERDATEN WHERE (BNNAME = ?)
bind => [XXXXX]
2009-11-10 17:14:27,725 INFO [STDOUT] [EL Fine]: 2009-11-10
17:14:27.725--ServerSession(24117517)--Connection(17349722)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--SELECT AUFTRAGSART,
BEZEICHNUNG, LISA_FAKTURA_KZ FROM IMPOC_AUFTRAGSART
2009-11-10 17:14:27,728 INFO [STDOUT] [EL Fine]: 2009-11-10
17:14:27.728--ServerSession(24117517)--Connection(17349722)- -Thread(Thread[UIThread
[DFBC934327891FCC0690B47F289C28F0],6,jboss])--SELECT FAKTURATYP,
BEZEICHNUNG FROM IMPOC_FAKTURATYP
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