Logical handle no longer valid

Question

I am getting the "logical handle no longer valid" SQLException when I reach the point in code marked by
Object[] oaResults = (Object[])saResults.getArray();
I can't explain this! I have talked to every Java developer I know without any answers. This code has been in implementation for the last whole year and has been working like a charm. All I changed recently was the Connection Pooling implementation to use Oracle's OracleConnectionCacheImpl class. I have my own FINAPPS_Connection wrapper around it. FINAPPS_Connection acts as a Singleton class.
All the connection, execution and closure of statements is happening in one method. This method gets connection from the Connection Pool, instantiates FINAPPS_OracleCallableStatement which is a wrapper around OracleCallableStatement class, prepares the OracleCallableStatement, sets and register's parameters, executes the query and reads the results in the STRUCTs returned by the callable statement object. It is fine reading one of the STRUCT, then it breaks down the second struct that contains a String object and an Array object. I am able to read the String object but when it starts to read the Array object, it breaks down and gives me the "Logical handle no longer valid" error.
Funny thing is, it doesn't happen all the time. It just happens randomly now and then. Sometimes it happens so often that a user can't do anything. In that case, I just try restarting the app server(JRun 3.0) which usually works!
There is only ONE operation that I do per connection per statement. I only FETCH. I never update or commit or do anything. All I need to do is submit user query and return results to the screen. Thats it. I close the connection and statement object right after I am done with them. So there should be no reason for connection to hang around and I am using one connection for one transaction so there should be no confusion there either.
Please help!!
Janmeet.
try
//connect to database for stored procedure call
FINAPPS_Connection m_cCon = connectToDB(hmDBParams);
//setup up the oracle callable statement
FINAPPS_OracleCallableStatement m_oCallableStmt = m_cCon.prepareOracleCall(getSpStmt(spName, placeHolder));
//set and register parameters
m_cCon.setRegParams(m_oCallableStmt, ht, DbNode);
/execute stored procedure
m_cCon.executeSP(m_oCallableStmt, 5);
//Obtain action Struct
STRUCT actionStruct = m_oCallableStmt.getSTRUCT(6);
Object[] actionAttrArray = actionStruct.getAttributes();
String theAction = (String)actionAttrArray[0];
logMsg("DatabaseManager.storedProcedure(): Action is: " + theAction, m_bPrintMsg);
m_sAction=theAction;
//Output Array
STRUCT arrayStruct = m_oCallableStmt.getSTRUCT(4);
Object[] outputAttrArray = arrayStruct.getAttributes();
String totalDollars = outputAttrArray[1].toString();
m_htStats.put("TotalDollarAmount", totalDollars.toString());
Array atrARR = (Array)outputAttrArray[0];
Array saResults = atrARR;
int rows = 0, cols = 0;
String szResult=null;
Object[] oaResults = (Object[])saResults.getArray();
rows = oaResults.length;
//Add the total number of rows in the Statistics Hashtable
Integer rowsObj = new Integer(rows);
m_htStats.put("TotalRows", rowsObj.toString());
StringBuffer sbTemp = new StringBuffer();
for(int i = 0; i < rows; i++)
Struct theResult = (Struct)oaResults;
if (theResult != null)
Object[] oaAttributes = ((Struct)oaResults).getAttributes();
cols = oaAttributes.length;
sbTemp.append("<row>");
for(int j = 0; j < cols; j++)
sbTemp.append("<colLabel>");
sbTemp.append(oaAttributes[j]);
sbTemp.append("</colLabel>");
sbTemp.append("</row>");
szResult = sbTemp.toString();
sbTemp=null;
szResult = "<Data>" + getHeader(rows, cols) + szResult + "</Data>";
setOutputArray(szResult);
setError(m_oCallableStmt);
m_oCallableStmt.close();
m_oCallableStmt=null;
m_cCon.close();
}

Answer 1

Logical handle no longer valid means your connection is stale. When using connection pooling it is sadly all too common to get handed out a connection from the pool that has actually timed out at the server side. If you look at eg the Jakarta Commons GenericDataSource they have a pingQuery property meant to support checking if a connection really is alive before handing it out, for this very reason.
The oracle pool (last time I used it - a year ago) was pretty bad for this, and didnt provide any api help for marking connections as invalid, or telling the driver how to test for this condition. Its not the only problem with the oracle drivers, or the worst, but at least its easily avoided. Use another connection pool implementation like the jakarta one or tyrex.