com.ibm.db2.jcc.am.SqlException: [jcc][10120][11936][4.14.88] Invalid operation: Lob is closed. ERRORCODE=-4470, SQLSTATE=null

Question

In our application we are having a simple POJO class that has a Clob attribute within it.

I am having issue in getting the String representation of that Clob entity.

Say I have already queried and cached the result in the POJO object, now I am trying to get the String value of the Clob as below.

int aLength = (int)myPojo.getClobField().length();
String aStringValue = myPojo.getClobField().getSubString(1L, aLength);

But the above execution gives me the error,

com.ibm.db2.jcc.am.SqlException: [jcc][10120][11936][4.14.88] Invalid operation: Lob is closed. ERRORCODE=-4470, SQLSTATE=null

Am I missing something?

Answer 1

The Clob Java object is not a copy of the CLOB value stored in the database. It is a locator (pointer), which becomes invalid after the result set is closed. You'll need to copy CLOB contents while processing the result set.

Answer 2

This issue can be solved by adding progressiveStreaming=2; argument to the connection url

The fully specified Connection URL is to be given as below:

jdbc:db2://localhost:50000/SAMPLE:progressiveStreaming=2;

In case you have exception on that parameter add the following to it or add any one or combinations of these parameters to fix it:

jdbc:db2://localhost:50000/SAMPLE:driverType=4;fullyMaterializeLobData=true;fullyMaterializeInputStreams=true;progressiveStreaming=2;progresssiveLocators=2;

It is preferred to use db2jcc4.jar

Answer 3

For hibernate users , when mapping to a database Lob type (BLOB or CLOB) the field should be annotated @Lob and no need to keep the copy , you can directely convert it in to character array like

(java.sql.Clob)payload.field1 bodyText = clobTest.getCharacterStream() 
 targetString = org.apache.commons.io.IOUtils.toString(bodyText) 
int length=targetString.length();
payload.PAYLOADHEADERS=targetString
return payload

Make sure you have added progressiveStreaming=2; in your data-source configuration properties.