A fix is available
APAR status
Closed as program error.
Error description
WHEN USING the IBM DB2 Analytics Accelerator for z/OS WITH QUERY ACCELERATION not= NONE AND DB2 DYNAMIC STATEMENT CACHING IS ENABLED, A DYNAMIC SELECT FROM A PACKAGE BOUND KEEPDYNAMIC (YES) INTERMITTENTLY FAILS WITH SQLCODE -198 FROM DB2 CSECT DSNHLEX. Other negative SQLCODES, INCLUDING SQLCODE301 and SQLCODE313 ARE ALSO POSSIBLE. THESE FAILURES DO NOT OCCUR UNDER KEEPDYNAMIC(NO). . Additional search keywords: IDAAV2R1/K IDAAV3R1/K SQLKEEPDYNAMIC SQLDYNSTMTCACHE
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All DB2 Users of dynamic SQL queries bound * * KEEPDYNAMIC(YES) and both IBM DB2 Analytics * * Accelerator and DB2 dynamic statement cache * * are active for the same DB2 thread or * * application * **************************************************************** * PROBLEM DESCRIPTION: SQLCODE198 from DB2 csect DSNHLEX for * * a dynamic query bound KEEPDYNAMIC YES * * when both DB2 QUERY ACCELERATION and * * dynamic statement caching are active * * for the DB2 thread or application. * * * * Other SQLCODEs including SQLCODE104, * * SQLCODE301, and SQLCODE313 are possible * * * * The following DB2 csect abends are also * * possible: * * ABEND0C4 RC00000038 DSNXEIST +0360 * * ABEND0C4 RC00000038 DSNXEUSC +034E * * ABEND0C4 RC00000038 DSNXEFB +045A * **************************************************************** * RECOMMENDATION: * **************************************************************** When using the IBM DB2 Analytics Accelerator for z/OS (IDAA) and both CURRENT QUERY ACCELERATION ^= NONE and DB2 dynamic stmt caching are active for the running DB2 thread, a dynamic query prepared and executed from a package bound KEEPDYNAMIC (YES) intermittently fails with SQLCODE -198 from DB2 Parser csect DSNHLEX. Other SQLCODEs, including SQLCODE104, SQLCODE301, and SQLCODE313 are also possible. The problem can also occur when, in addition to all the above conditions, PREPARE attribute CONCENTRATE STATEMENTS WITH LITERALS is also used. . These failures do not occur when using KEEPDYNAMIC(NO) or CURRENT QUERY ACCELERATION = NONE (the default). . Problem occurred when a query that was not accelerated to IDAA (because it did not qualify) but instead was cached in the DB2 dynamic statement cache (DSC), and that cached query was LRU'd or otherwise invalidated out of the global DSC while the query was being run by the application, causing DB2 to do an implicit re-prepare for the query when it is run after a COMMIT (due to KEEPDYNAMIC YES ). . The SQLCODES occurred because DB2 incorrectly allowed the failing DB2 thread's copy of the statement text and internal statement block to be freed after detecting that the cached copy of the statement was 'invalidated'. This only occurs when IDAA and QUERY ACCELERATION are also active for the same DB2 thread, even though the failing query is *not* accelerated to IDAA. . Other possible symptoms include, the following abends in DB2 csects: ABEND0C4 RC00000038 DSNXEIST +0360 ABEND0C4 RC00000038 DSNXEUSC +034E ABEND0C4 RC00000038 DSNXEFB +045A
Problem conclusion
DB2 was changed to not incorrectly free the DB2 thread's local copy of both the cached statement's text and internal control block in the scenario previously described. . Additional search keywords: IDAAV2R1/K IDAAV3R1/K SQLKEEPDYNAMIC SQLDYNSTMTCACHE SQLCODE198 SQLCODE104 SQLCODE301 SQLCODE313 AB0C4 RC38 OFFSET360 OFFSET34E OFFSET45A
Temporary fix
AM87668
Comments
APAR Information
APAR number
PM87668
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
A10
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2013-04-23
Closed date
2013-07-12
Last modified date
2013-08-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK95797 UK95798
Modules/Macros
DSNXEDP DSNXEDSC
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
Fix is available
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Document Information
Modified date:
02 August 2013