[OPENJPA-2235] "READ_UNCOMMITTED" setting for the fetch plan isolation level is ignored in DB2Dictionary

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.1.1, 2.2.0, 2.3.0
• Fix Version/s: 2.1.2, 2.2.2, 2.2.1.1, 2.3.0
• Component/s: performance, query
• Patch Info: Patch Available
• Assignee: Helen Xu
• Reporter: Helen Xu
• Created: 19/Jul/12 15:55
• Updated: 10/Apr/13 16:04
• Resolved: 10/Apr/13 16:04

Description

When user set query hint as shown below for db2, no "with UR" clause append to the query. The setting is ignored.
query.setHint("openjpa.FetchPlan.Isolation", "READ_UNCOMMITTED");

Uncommitted read is very risky and should be avoid if it is possible. JPA specification requires a minimum of read-committed isolation to ensure no "dirty read" and "non-repeatible read" can occur. Use of read-uncommitted isolation may cause data integrity problem.