[hibernate-issues] [Hibernate-JIRA] Created: (HHH-3507) MultipleHiLoPerTableGenerator can contain stale hi value, generate duplicate IDs

[Christopher Wong (JIRA)]

MultipleHiLoPerTableGenerator can contain stale hi value, generate duplicate IDs
--------------------------------------------------------------------------------

                 Key: HHH-3507
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3507
             Project: Hibernate Core
          Issue Type: Bug
          Components: core
    Affects Versions: 3.3.0.SP1
         Environment: Hibernate 3.3.0SP1 on MySQL 5.0.37-community-nt
            Reporter: Christopher Wong


An instance of MultipleHiLoPerTableGenerator seems to be created per table (and per schema?). This instance seems to persist across DB sessions/transactions, retaining the "hi" value that it last loaded from the generator table. The problem comes when the generator retains this "hi" value across a DB reset. It is not unusual to reinitialize a schema for a new customer, or to restore a backup dump. The problem is that when a DB is reset, this "hi" value is no longer valid, causing the IDs to wrap around and eventually duplicate. Example sequence:

generate ID 195
generate ID 196

<DB reset.>

generate ID 197
generate ID 198
generate ID 199

<max lo reached. Load new "hi" value from DB.>

generate ID 1
generate ID 2
... (etc) ...
generate ID 196
generate ID 197 (ID is now duplicated, causing NonUniqueObjectException)

Perhaps the generator can recheck the generator table at the beginning of a transaction to ensure its hi value is consistent.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira