ODBC SQLCloseCursor or SQLFreeHandle does not free the memory of CLOB field in Oracle.

Hi,

I am using a C++ application that connects to Oracle Database using
EasySoft ODBC driver.
I face a strange problem when freeing the memory after i fetch the CLOB
data from the Oracle table.

The piece of Code is below,

char *pClobBuffer = new char[10485670]; // 10 MB

// Prepare the SQL statement for fetching the mgcRoute Table.
strcpy(pQuery, "SELECT clobdata FROM clobtable")

/* Execute the SQL statement. Check for errors. */
SQLExecDirect(stmtHandle,(SQLCHAR*)pQuery,SQL_NTS);
SQLFetch(stmtHandle);
SQLGetData(stmtHandle, 1, SQL_C_CHAR, pClobBuffer,10485670,&dError);
SQLCloseCursor(stmtHandle);
delete []pClobBuffer;

The statement and connection handle is closed properly. Still i am
seeing the memory usage is exactly increasing by 10 MB(size of the
buffer we allocated to read the CLOB) for each query.

This is not a memory leak, it's only the memory usage which is
increasing for the process for every query involving this CLOB field.

I tried changing the CLOB to Varchar in the database table, the above
piece of Code works without increase in memory usage.

NOTE: We observed there is some special handling required to free the
memory buffer allocated to read the CLOB field. In DB2 site they are
saying SQLFreeStmt does not free the CLOB fields, FREE Alocator
statement must be used. Please see the below link which i refered, but
this one is for DB2.

http://publib.boulder.ibm.com/infocenter/db2help/index.jsp?topic=/com.ibm.db2.udb.doc/ad/t0007404.htm

Please suggest me if any special handling is required for ORACLE to
free the CLOB data.

Our Env: C++, Solaris, ODBC, ORACLE, EasySoft driver

thanks,
Vadivel.

.

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