[ROL-1760] Scheduled tasks do not run on Oracle (or other DBs with high precision timestamps)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0
• Fix Version/s: 5.0
• Component/s: Data Model & JPA Backend
• Environment: Solaris 10, Oracle 10gR2, Roller 4.0.1
• Database: oracle 10g
• JDK Version: 1.6
• Level of effort: 0.5h
• O/S Version: Solaris 10
• Assignee: David Johnson
• Reporter: Dick Davies
• Created: 20/Nov/08 16:24
• Updated: 11/Jan/16 03:16
• Resolved: 03/Oct/09 14:15

Description

Rollers JPA config seems to assume that CURRENT_TIMESTAMP is low precision
(i.e. hundredths of a second).

Specifically, I'm not sure the ORM config in TaskLock.orm.xml is correct.

On databases that have microsecond resolution (Oracle, PostgreSQL, etc.) the
JPAThreadManagerImpl.registerLease() method quickly gets into a state where the

"TaskLock.updateClient&Timeacquired&Timeleased&LastRunByName&Timeacquired" NamedUpdate never suceeds,

and so tasks never run.
(There was a similar issue with DB2 that resulted in us dumping that , so it's not all bad )

I turned on JPA debugging and on Oracle 10, we see

DEBUG 2008-11-20 15:30:00,064 CommonsLogFactory$LogAdapter:trace - Executing query: [UPDATE TaskLock t SET t.clientId=?1, t.timeAquired= CURRENT_TIMESTAMP, t.timeLeased= ?2, t.lastRun= ?3 WHERE t.name=?4 AND t.timeAquired=?5 AND ?6 < CURRENT_TIMESTAMP] with parameters:

{3=Thu Aug 07 16:07:00 BST 2008, 2=PingQueueTask, 1=2008-08-07 16:37:00.07, 6=2008-11-20 15:30:00.0, 5=30, 4=devel-roller01}

DEBUG 2008-11-20 15:30:00,065 CommonsLogFactory$LogAdapter:trace - <t 28169327, conn 12589755> executing prepstmnt 11980159 UPDATE roller_tasklock t0 SET timeleased = ?, client = ?, lastrun = ?, timeacquired = CURRENT_TIMESTAMP WHERE (t0.name = ? AND t0.timeacquired = ? AND ? < CURRENT_TIMESTAMP) [params=(int) 30, (String) devel-roller01, (Timestamp) 2008-11-20 15:30:00.0, (String) PingQueueTask, (Timestamp) 2008-08-07 16:07:00.07, (Timestamp) 2008-08-07 16:37:00.07]

TIMEACQUIRED at that time was '07-AUG-08 04.07.00.069896 PM', and since Oracle checks down to the microsecond
when comparing timestamps, this means the WHERE clause never matches and nothing updates.

The WHERE clause seems overly picky in any case -
the schema creation scripts declare the roller_tasklock.name column to be unique, so 'WHERE to.name = ?' is enough
to find the right row, surely?

Another fix is to declare the timestamp columns as timestamp(2) in the Oracle
(+DB2 + PostgreSQL ? ) creation scripts. We're trying that now to see if it helps.

Do you want a bug filed?