fix(db2): read CLOB query values as text

Closes #8532

agents/drivers/db2/src/main/java/com/dbx/agent/db2/Db2Agent.java

@@ -19,6 +19,7 @@ import com.dbx.agent.TableInfo;
 import com.dbx.agent.TriggerInfo;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.sql.Types;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -389,6 +390,10 @@ public final class Db2Agent extends AbstractJdbcAgent {
     @Override
     protected Object resultValue(ResultSet rs, int index, int sqlType) {
         return unchecked(() -> {
+            if (sqlType == Types.CLOB || sqlType == Types.NCLOB) {
+                String value = rs.getString(index);
+                return rs.wasNull() ? null : value;
+            }
             Object value = rs.getObject(index);
             return rs.wasNull() ? null : value == null ? null : value.toString();
         });

agents/drivers/db2/src/test/java/com/dbx/agent/db2/Db2AgentTest.java

@@ -18,6 +18,7 @@ import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.Statement;
+import java.sql.Types;
 import java.util.Arrays;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -50,6 +51,25 @@ class Db2AgentTest extends JdbcFakeExecutionBehaviorTest {
         assertEquals("jdbc:db2://db.example.com:50000/SAMPLE:sslConnection=true;", Db2Agent.buildUrl(params));
     }
 
+    @Test
+    void readsClobValuesAsTextInsteadOfVendorObjectNames() {
+        Db2Agent agent = new Db2Agent();
+        ResultSet resultSet = proxy(ResultSet.class, new MethodHandler() {
+            @Override
+            public Object handle(Method method, Object[] args) {
+                if ("getString".equals(method.getName())) {
+                    return "long text value";
+                }
+                if ("wasNull".equals(method.getName())) {
+                    return false;
+                }
+                return defaultValue(method.getReturnType());
+            }
+        });
+
+        assertEquals("long text value", agent.resultValue(resultSet, 1, Types.CLOB));
+    }
+
     @Test
     void listsAllCatalogSchemasWithoutOwnerTypeFiltering() {
         Db2Agent agent = new Db2Agent();