fullymaterializeLobData property for db2 jdbc driver

[rjha94]

Hi Folks

we have a java application using hibernate ORM mapper on top of db2
UDB v9. we are using type 4 jdbc drivers for connections.

Now the issue is we have a table with BLOB column and when you issue
a query against this table, all the blob data are fetched into JVM
memory. Needless to say this does not look like a scalable design. You
can set some properties on db2 jdbc driver
(fullymaterializelobData=false) to stream the lobs instead of fetching
them in memory.

I looked up the hibernate docs and it looks like i can pass customized
properties using hibernate.connection.<propertyNameto turn off this
behavior. (http://www.hibernate.org/hib_docs/re.../html/session-
configuration.html)

Question is how do I verify that JDBC driver is honoring this property
(what I set from hibernate config) ? where are the driver logs kept
that tell me the values of all properties being used? Or do I have to
turn the JDBC trace for my session?

tia and regards

- rajeev.

[rjha94]

On Jun 12, 11:16 pm, rjha94 <[e-mail]:

Hi Folks

we have a java application using hibernate ORM mapper on top of db2
UDB v9. we are using type 4 jdbc drivers for connections.

Now the issue is we have a table with BLOB column and when you issue
a query against this table, all the blob data are fetched into JVM
memory. Needless to say this does not look like a scalable design. You
can set some properties on db2 jdbc driver
(fullymaterializelobData=false) to stream the lobs instead of fetching
them in memory.

I looked up the hibernate docs and it looks like i can pass customized
properties using hibernate.connection.<propertyNameto turn off this
behavior. (http://www.hibernate.org/hib_docs/re.../html/session-
configuration.html)

Question is how do I verify that JDBC driver is honoring this property
(what I set from hibernate config) ? where are the driver logs kept
that tell me the values of all properties being used? Or do I have to
turn the JDBC trace for my session?

tia and regards

- rajeev.

Allright. Here is how to do it with hibernate . write the following
driver-specific properties in your hibernate config file.
I think this is equivalent of providing the properties on JDBC
connection URL. You can check the driver trace file where it says
about the value of fullyMaterializeLobData property.

<!-- pass the JDBC property custom_property to
DriverManager.getConnection -->
<property name="hibernate.connection.fullyMaterializeLobData ">false</
property>
<!-- set trace -->
<property name="hibernate.connection.traceDirectory">c:\\nuk e</
property>
<property name="hibernate.connection.traceFile">trace</property>
<property name="hibernate.connection.traceLevel">-1</property>