Re: [Repost with more data]RE: Connection pooling and HSQL

[Armin Waibel]

Hi Raghavan,

Kollivakkam R. Raghavan wrote:

I didn't get any responses yet.  Am trying again with more information.
If some guru out there has an answer, I would really appreciate a
response.
sorry, I'm not a guru, but I will try my best ;-)

I'm including a part of the web server logs that shows the
message I am talking about.   After a few calls the connections seem to
spontaneously close.  Is this an HSQL issue?  Something known?
...
> Validation query for connection failed, discard connection. Query was
> select count(*) from role, Message was Connection is closed
...
The message says that the validation query fails, than OJB try to close 
the Connection instance and remove it from pool. The error message was 
"Connection is closed", this could have two (maybe more) reasons:

- Connection was timed out and hsql close it itself.

- In your code you lookup a connection instance from OJB, e.g. using 
ConnectionManager and do an (not allowed) con.close() call on the 
connection, then next time OJB try to use this connection will find an 
closed one.

regards,
Armin
Thanks in advance 
Raghavan

--------WEB SERVER LOG SEGMENT-------------
Validation query for connection failed, discard connection. Query was 
select count(*) from role, Message was Connection is closed 13-Feb-2004
12:07:40 INFO  [  CPS-Promotion] 
slayer.ConnectionFactoryPooledImpl
Destroy object was called, try to close connection: 
[EMAIL PROTECTED]
13-Feb-2004 12:07:40 WARN  [  CPS-Promotion] 
slayer.ConnectionFactoryPooledImpl
Validation query for connection failed, discard connection. Query was 
select count(*) from role, Message was Connection is closed 13-Feb-2004
12:07:40 INFO  [  CPS-Promotion] 
slayer.ConnectionFactoryPooledImpl

-----------------

-----Original Message-----
From: Kollivakkam R. Raghavan [mailto:[EMAIL PROTECTED] 
Sent: Thursday, February 12, 2004 4:53 PM
To: 'OJB Users List'
Subject: Connection pooling and HSQL

I am using OJB with HSQL and the following connection descriptor in a
Struts based web application.  I very frequently see a message saying
that the connection was closed and destroy object was called.  It
appears as if the connection pooling is not working as it should.  Am I
missing a setting - or is this a known issue.  I could add
whenExhaustedAction=2 to work around it but want to know the root cause.
Thanks in advance. Raghavan
<jdbc-connection-descriptor 
        jcd-alias="default" 
        default-connection="true" 
        platform="Hsqldb" 
        jdbc-level="3.0" 
        driver="org.hsqldb.jdbcDriver" 
        protocol="jdbc" 
        subprotocol="hsqldb:hsql" 
        dbalias="//localhost" 
        username="sa" 
        password="" 
        eager-release="false" 
        batch-mode="false" 
        useAutoCommit="0" 
        ignoreAutoCommitExceptions="false"
    >
    <connection-pool maxActive="21" validationQuery="select count(*)
from role"/>
    <sequence-manager
className="org.apache.ojb.broker.util.sequence.SequenceManagerHighLowImp
l">
        <attribute attribute-name="autoNaming" attribute-value="true"/>
        <attribute attribute-name="grabSize" attribute-value="20"/>
        <attribute attribute-name="globalSequenceId"
attribute-value="false"/>
        <attribute attribute-name="globalSequenceStart"
attribute-value="10000"/>
    </sequence-manager>
</jdbc-connection-descriptor>

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