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From "Rakesh Jain (JIRA)" <j...@apache.org>
Subject [jira] [Created] (OPENJPA-2352) Retrieving column index for non existing field throws SQLException (ignored) causing slowness in application server
Date Sat, 16 Mar 2013 01:46:12 GMT
Rakesh Jain created OPENJPA-2352:
------------------------------------

             Summary: Retrieving column index for non existing field throws SQLException (ignored)
causing slowness in application server
                 Key: OPENJPA-2352
                 URL: https://issues.apache.org/jira/browse/OPENJPA-2352
             Project: OpenJPA
          Issue Type: Bug
          Components: jdbc
    Affects Versions: 2.1.1
         Environment: All OS, I have tried with DB2 but problem may exist for all databases.
WebSphere.
            Reporter: Rakesh Jain


When we have defined NamedNativeQuery and the query contains let's say 4 columns. Now if we
have a resultClass associated to that query which is simply a POJO having let's say five fields,
four of which are mapped to the 4 columns of the NamedNativeQuery, but the fifth one is not
(after all it is POJO), the JPA tries to retrieve column index for that fifth field, and that
throws SQL exception. The JPA code though ignores this exception, returning zero for column
index. However, because an exception is throws, the application server in which this code
is executing captures it and logs it in its corresponding logs. This causes the population
of the result bean slow, and very slow if there are 4-5 or more fields unmapped.

Here's the code fragment from org.apache.openjpa.jdbc.sql.ResultSetResult.java where this
is happening.

/**
* Return the 1-based result set index for the given column or id, or a
* non-positive number if the column is not contained in this result.
*/
protected int findObject(Object obj, Joins joins)
throws SQLException {
try {
String s1 = obj.toString();
DBIdentifier sName = DBIdentifier.newColumn(obj.toString());
return getResultSet().findColumn(_dict.convertSchemaCase(sName));
} catch (SQLException se) {
return 0;
}
}
Moreover, this same method is called multiple times for each field, multiplying the problem.

I would think a better approach would be to use ResultSetMetaData to retrieve all the column
names and indexes, cache them and simply return from that cache in the findObject method.

Is there any reason to keep it like this and not change to use metadata?

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