Subscribe to this APAR
By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.
APAR (Authorized Program Analysis Report) |
Abstract
LIC-DB-OTHER-PERFM PESSIMISTIC INDEX SCAN COSTING IS INFLATING
*CS STACKED TABLE PROBE NODE COST
Error Description
DB2Connect (QRWTSRVR / failing) had extremely long processing
time to return results. Exact same query from Run SQL Scripts
(QZDASOINIT) works just fine.
Under some circumstances, including the use a commit control
level of *CS (Cursor Stability), queries that specify ordering
may run slowly. The optimizer may overestimate the cost of an
access plan that uses an index scan to provide ordering and may
choose a less efficient ordering method.
Problem Summary
Please see the ERROR DESCRIPTION section.
Problem Conclusion
The optimizer was using pessimistic costing in situations in
which it was not appropriate. The optimizer logic has been
improved to avoid using pessimistic costing for these
situations.
Temporary Fix
Comments
Circumvention
PTFs Available
R720 MF65210 9123
R730 MF65174 9116
Affected Modules
Affected Publications
Summary Information
Status............................................ | CLOSED PER |
HIPER........................................... | Yes |
Component.................................. | 9400DG3DB |
Failing Module.......................... | RCHMGR |
Reported Release................... | R730 |
Duplicate Of.............................. |
System i Support
IBM disclaims all warranties, whether express or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. By furnishing this document, IBM grants no licenses to any related patents or copyrights. Copyright © 1996,1997,1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 IBM Corporation. Any trademarks and product or brand names referenced in this document are the property of their respective owners. Consult the Terms of use link for trademark information
Document Information
Modified date:
17 May 2019