labels upgrade task 552 is sooooooo slow

    void migrateCustomFieldData(final List<Long> fieldsToConvertToSystem, final List<Long> customFieldIds)
    {
        //Copy the data across for all custom fields!
        OfBizListIterator iterator = null;
        try
        {
            iterator = ofBizDelegator.findListIteratorByCondition(CF_VALUE_ENTITY, new EntityExpr("customfield", EntityOperator.IN,
                    customFieldIds), null, EasyList.build("issue", "customfield", VALUE), null, null);
            final List<GenericValue> labelRows = new ArrayList<GenericValue>(BATCH);
            int i = 0;

            for (GenericValue gv = iterator.next(); gv != null; gv = iterator.next())
            {
                final Long issueId = gv.getLong("issue");
                final Long customFieldId = gv.getLong("customfield");
                final Collection<String> labels = LabelParser.buildFromString(new PassStringThrough(), gv.getString(VALUE));
                if (labels != null)
                {
                    final Map<String, Object> params = MapBuilder.<String, Object>newBuilder().add(OfBizLabelStore.Columns.ISSUE_ID, issueId).toMutableMap();
                    if (!fieldsToConvertToSystem.contains(customFieldId))
                    {
                        params.put(OfBizLabelStore.Columns.CUSTOM_FIELD_ID, customFieldId);
                    }
                    for (String label : labels)
                    {
                        params.put(OfBizLabelStore.Columns.LABEL, label);
                        labelRows.add(createValue(OfBizLabelStore.TABLE, params));
                        if(++i == BATCH) {
                           ofBizDelegator.storeAll(labelRows);
                           labelRows.clear();
                           i = 0;
                        }
                    }
                }
            }
            ofBizDelegator.storeAll(labelRows);
        }
        catch(GenericEntityException gee) {
           throw new DataAccessException(gee);
        }
        finally
        {
            if (iterator != null)
            {
                iterator.close();
            }
        }
    }

   /**
    * Create a new entity.
    *
    * If there is no "id" in the parameter list, one is created using the entity sequence
    */
   // From EntityUtils
   private static GenericValue createValue(final String entity, final Map<String, ? extends Object> paramMap) throws GenericEntityException
   {
       final Map<String, Object> params = (paramMap == null) ? new HashMap<String, Object>() : new HashMap<String, Object>(paramMap);

       if (params.get("id") == null)
       {
           final Long id = CoreFactory.getGenericDelegator().getNextSeqId(entity);
           params.put("id", id);
       }

       return CoreFactory.getGenericDelegator().makeValue(entity, params);
   }