Hi Christian,
Christian Lipp wrote:
Hi Armin,
thank you for quick answer and sorry for my long delay.
We are using an older OJB version (1.0.1.x), so I thought I cannot use your
recommendation and wanted to perform a backport now.
I got the actual OJB now and examined it, but also couldn't find an
attribute in the jdbc-connection-descriptor (I checked the repository.dtd).
So I asume I have to implement the JDBC transaction level as attribute for
jdbc-connection-descriptor into OJB or do I miss something?
Some databases support transaction-isolation settings by append a
property in the database URL - e.g. maxDB:
dbalias="//localhost/ojb?isolation=TRANSACTION_READ_COMMITTED
Additionally you can specify connection/database properties as custom
attributes with prefix "jdbc.".
<jdbc-connection-descriptor
....
>
<attribute attribute-name="jdbc.xyz" attribute-value="zxy" />
</jdbc-connection-descriptor>
OJB will set these properties (with jdbc.* prefix) when create the
connection:
Connection con = DriverManager.getConnection(url, properties);
Could someone point me in the right direction for this implementation? I
assume I have to read the attribute and apply it in the function
PlatformDefaultImpl.initializeJdbcConnection.
If your database doesn't support isolation setting shown above, you can
indeed extend a existing Platform class and override
#initializeJdbcConnection. Within this method you can easily get custom
attributes using:
<jdbc-connection-descriptor
platform="org.apache.ojb.broker.platforms.PlatformMyOwnImpl"
....
>
<attribute attribute-name="isolation" attribute-value="READ_COMMITED" />
</jdbc-connection-descriptor>
class PlatformMyOwnImpl extends PlatformMySQLImpl{
...
public void initializeJdbcConnection(Connection conn)
{
String isolation = jcd.getAttribute("isolation", null);
...
}
}
All shown solutions will work with latest OJB source
http://www.mail-archive.com/ojb-user%40db.apache.org/msg16078.html
I don't check the older versions.
regards,
Armin
Thanks in advance, CL
-----Original Message-----
From: Armin Waibel [mailto:[EMAIL PROTECTED]
Sent: Freitag, 25. Jänner 2008 03:03
To: OJB Users List
Subject: Re: Isolation level
Hi Christian,
Christian Lipp wrote:
I am still looking for an solution for my lock level settings and
therefore I am digging through the OJB source.
What I am not sure at the moment is if the setting of the
isolation-level is generally ignored in OJB?
<descriptor-repository version="1.0" isolation-level="read-comitted">
I couldn't find the place in the OJB code where the isolation level is
set to the DescriptorRepository and later to the connection.
In my optionion the isolation-level in the XML file is ignored.
Could someone point me in the right direction?
Out of the box the isolation-level setting is only used by the ODMG-api
which use pessimistic locking by default.
http://db.apache.org/ojb/docu/guides/lockmanager.html#Pessimistic-Locking
The PB-api doesn't use pessimistic locking, thus it will ignore these
settings.
The database transaction levels are completely independent from the
isolation-level setting in OJB. So you can use different database
transaction levels (e.g. as property in the dbalias attribute in the
jdbc-connection-descriptor)
regards,
Armin
Thanks in advance,
CL
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