We invite you to shape the future of IBM, including product roadmaps, by submitting ideas that matter to you the most. Here's how it works:
Post your ideas
Post ideas and requests to enhance a product or service. Take a look at ideas others have posted and upvote them if they matter to you,
Post an idea
Upvote ideas that matter most to you
Get feedback from the IBM team to refine your idea
Help IBM prioritize your ideas and requests
The IBM team may need your help to refine the ideas so they may ask for more information or feedback. The product management team will then decide if they can begin working on your idea. If they can start during the next development cycle, they will put the idea on the priority list. Each team at IBM works on a different schedule, where some ideas can be implemented right away, others may be placed on a different schedule.
Receive notification on the decision
Some ideas can be implemented at IBM, while others may not fit within the development plans for the product. In either case, the team will let you know as soon as possible. In some cases, we may be able to find alternatives for ideas which cannot be implemented in a reasonable time.
Apar PM89016 was created several years ago to implement the lock avoidance for singleton SELECTs with
ISO(CS) and CD(YES) when R-scan is used, or the index that is chosen has
matching predicates on all columns of the index.
Recently a new Apar PH19483 (UI67378) has reverted this behaviour to avoid receiving unexpected SQLCODE +100 when there is INSERT/DELETE/UPDATE activity happening concurrently on the same table.
As can be read on the text of such new Apar PH19483:
Db2 code is changed to acquire locking for singleton SELECTs meeting the criteria described above. As a result of this change, the user may see increased locking activity and slower query performance for such singleton SELECTs; the locking is mandatory to prevent concurrent operations from causing the incorrect output. If the user desires less locking activity, consider using CURRENTDATA(NO). "
In our case (Bankinter) 80% of our read Accesses are Singleton Selects, resolved with skinny index-to-data (equal predicates on all index columns) access instead of Cursors, so the impact of not "profiting" of lock avoidance feature on those singleton Selects with ISO(CS) and CD(YES) is huge. Furthermore We can't use CURRENTDATA(NO) due to our business processes read with Singleton Select most of the times, but they also read by read-only (or ambiguous) cursors and modify afterwards with Delete or Update statements.
Do not place IBM confidential, company confidential, or personal information into any field.