Schedule QueueEntry with ScheduleItem in customized queue is slow to execute in Windchill PDMLink

SELECT 'wt.scheduler.ScheduleHistory',TO_CHAR(A0.completionTime,'dd mm yyyy hh24:mi:ss'),....
FROM ScheduleHistory A0 
WHERE ((A0.idA3B4 = ?)) AND (A0.markForDeleteA2 = 0) 
ORDER BY A0.submissionTime DESC

wt.pds.BasicResultCursor.getNextResultSet(BasicResultCursor.java:273)
wt.pds.BasicResultCursor.advance(BasicResultCursor.java:234)
wt.pds.BasicResultCursor.next(BasicResultCursor.java:82)
wt.pds.SQLDatabasePds.query(SQLDatabasePds.java:837)
wt.pom.PersistentObjectManager.query(PersistentObjectManager.java:1076)
wt.pom.PersistentObjectManager.query(PersistentObjectManager.java:985)
wt.fc.StandardPersistenceManager._query(StandardPersistenceManager.java:1972)
wt.fc.StandardPersistenceManager._find(StandardPersistenceManager.java:2008)
wt.fc.StandardPersistenceManager.find(StandardPersistenceManager.java:655)
wt.fc.StandardPersistenceManager.find(StandardPersistenceManager.java:407)
sun.reflect.GeneratedMethodAccessor43.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
wt.services.ServiceFactory$ServerInvocationHandler.invoke(ServiceFactory.java:399)
com.sun.proxy.$Proxy18.find(Unknown Source)
wt.scheduler.ScheduleItem.getLatestSchedHistory(ScheduleItem.java:417)
wt.scheduler.StandardSchedulingService.executionKernel(StandardSchedulingService.java:1154)
wt.scheduler.StandardSchedulingService.executeScheduledItem(StandardSchedulingService.java:605)
sun.reflect.GeneratedMethodAccessor224.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
wt.queue.ScheduleQueueEntry.execute(ScheduleQueueEntry.java:264)
wt.queue.ScheduleQueue.execEntry(ScheduleQueue.java:336)
wt.queue.ScheduleQueue.execEntries(ScheduleQueue.java:457)
wt.queue.ScheduleQueueThread.processReadyEntries(ScheduleQueueThread.java:280)
wt.queue.ScheduleQueueThread.run(ScheduleQueueThread.java:88)

wt.pds.BasicResultCursor.getNextResultSet(BasicResultCursor.java:273)
wt.pds.BasicResultCursor.advance(BasicResultCursor.java:234)
wt.pds.BasicResultCursor.next(BasicResultCursor.java:82)
wt.pds.SQLDatabasePds.query(SQLDatabasePds.java:837)
wt.pom.PersistentObjectManager.query(PersistentObjectManager.java:1076)
wt.pom.PersistentObjectManager.query(PersistentObjectManager.java:985)
wt.fc.StandardPersistenceManager._query(StandardPersistenceManager.java:1972)
wt.fc.StandardPersistenceManager.query(StandardPersistenceManager.java:1465)
wt.fc.StandardPersistenceManager.query(StandardPersistenceManager.java:1123)
wt.scheduler.StandardSchedulingService.previousExecutingScheduleStatus(StandardSchedulingService.java:2228)
wt.scheduler.StandardSchedulingService.executionKernel(StandardSchedulingService.java:1165)
wt.scheduler.StandardSchedulingService.executeScheduledItem(StandardSchedulingService.java:605)
sun.reflect.GeneratedMethodAccessor224.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
wt.queue.ScheduleQueueEntry.execute(ScheduleQueueEntry.java:264)
wt.queue.ScheduleQueue.execEntry(ScheduleQueue.java:336)
wt.queue.ScheduleQueue.execEntries(ScheduleQueue.java:457)
wt.queue.ScheduleQueueThread.processReadyEntries(ScheduleQueueThread.java:280)