[OPENJPA-736] Combine insert and select SQL together for generated Id strategy=GenerationType.IDENTITY

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.3.0
• Fix Version/s: 1.3.0, 2.0.0-M2
• Assignee: Milosz Tylenda
• Reporter: Fay Wang
• Created: 01/Oct/08 16:27
• Updated: 09/Mar/10 18:31
• Resolved: 31/May/09 09:58

Description

Currently if the strategy of the generated id is GenerationType.IDENTITY, when an entity object is created, openjpa will generate two SQL statements. The following is an example running on DB2:

(1) INSERT INTO EntityA (col1, col2, col3, version) VALUES (?, ?, ?, ?)
[params=(int) 1, (int) 1, (int) 1, (int) 1]

(2) SELECT IDENTITY_VAL_LOCAL() FROM SYSIBM.SYSDUMMY1

A performance improvement is to take advantage of the "select from final table" feature in DB2 to combine the insert and select statement into a single SQL statement as shown below:

SELECT id FROM FINAL TABLE (INSERT INTO EntityA (col1, col2, col3, version) VALUES (?, ?, ?, ?) )

Issue Links

• is blocked by: OPENJPA-847 Retrieving database generated keys gets never enabled