A fix is available
APAR status
Closed as new function.
Error description
DB2 10 for z/OS new function. Customers may also see ABND=04E-00D35011 LOC=DSNLZGLM.DSNLZRCD:0057 Additional keywords and symptoms: ******************************** ABND04E 00D35011 RC00D35011 DSNLZRCD ABNDID0057 0057
Local fix
n/a
Problem summary
**************************************************************** * USERS AFFECTED: All DB2 10 for z/OS users of DB2 * * acceleration for dynamic queries who * * also what to use DB2 Dynamic Statement * * Caching for those accelerated dynamic * * queries. * * * * * * * **************************************************************** * PROBLEM DESCRIPTION: The use of an accelerator enables high * * performance for executing complex * * analytic queries. Prior to this new * * function APAR, DB2 for z/OS did not * * support Dynamic Statement Caching for * * accelerated dynamic queries so a * * PREPARE of an accelerated dynamic * * query required the "full" non-cache * * prepare process without the benefit * * of statement caching that is available * * to dynamic queries that do not run * * accelerated. * * * * * * * * * * * * * * * * * * * * * * * **************************************************************** * RECOMMENDATION: * **************************************************************** This new function APAR now extends Dynamic Statement Cache (DSC) support to dynamic queries that are accelerated to an accelerator. This significantly improves performance of PREPAREs for accelerated dynamic queries because these PREPAREs can now benefit from the usage of the DSC as do queries that are not accelerated. . No changes are needed to enable Dynamic Statement Cache support for accelerated dynamic queries if Dynamic Statement Caching is already enabled for the DB2 subsystem. . This APAR introduces the following changes to the DB2 table DYNAMIC_STATEMENT_CACHE_TABLE: (1) New CHAR(10) column ACCELERATED is added. ACCELERATED identifies whether a cached dynamic query was prepared for acceleration to an accelerator server. . Possible values for column ACCELERATED are: NO The cached statement was not prepared for acceleration. This is the default value for a cached dynamic statement. This is also the value for a cached query under the following conditions: - The QUERY ACCELERATION behavior was not specified or was explicitly set to NONE when the dynamic query was prepared. - A QUERY ACCELERATION behavior other than ALL was specified when the dynamic query was prepared, but DB2 did not prepare the query for acceleration because the query did not qualify for acceleration according to the QUERY ACCELERATION behavior specified. DB2 will consider this cache entry as a possible cache match during any of these prepare scenarios previously described, unless a QUERY ACCELERATION behavior is specified but the query can never be accelerated (see the description of the column value NEVER below). . YES The cached query was prepared for acceleration to an accelerator server when a QUERY ACCELERATION behavior was specified. If a QUERY ACCELERATION behavior is specified when a dynamic query is prepared, DB2 can consider this cache entry for a possible cache match during the prepare of the dynamic query. If the QUERY ACCELERATION behavior is not specified or is explicitly set to NONE when the query is prepared, DB2 will not consider this cache entry for a cache matched during the prepare. . NEVER The cached query was not prepared for acceleration when a QUERY ACCELERATION behavior was specified for the prepare, because the query can never be accelerated. If the QUERY ACCELERATION behavior is set to ENABLE, ENABLE WITH FAILBACK, or ELIGIBLE for the prepare of the query, DB2 will consider this cache entry first as a possible cache match during the prepare, to verify if the query has been previously cached as 'never can be accelerated'. If the QUERY ACCELERATION behavior is set to ALL for the prepare of the query, DB2 will not consider this cache entry as a possible cache match during the prepare. If the QUERY ACCELERATION behavior is not specified or is explicitly set to NONE for the prepare of the query, DB2 will not consider this cache entry as a possible cache match during the prepare. . With this APAR/PTF applied, when QUERY ACCELERATION behavior is used for a DB2 subsystem that has DB2 Dynamic Statement Caching (DSC) active, it is possible for a cached query to have multiple entries in the DSC, which is then reflected in the table DSN_STATEMENT_CACHE_TABLE. This can occur if the same dynamic query is run by applications that do not use QUERY ACCELERATION, as well as, by applications that "do" use QUERY ACCELERATION on the same DB2 subsystem. . Query acceleration behavior is specified by either the DB2 subsystem parameter QUERY_ACCELERATION, the QUERYACCELERATION bind option, or the CURRENT QUERY ACCELERATION special register. The precedence order (lowest to highest) is: The QUERY_ACCELERATION subsystem parameter The QUERYACCELERATION bind option, if specified An explicit SET CURRENT QUERY ACCELERATION statement . (2) This APAR also introduces these additional columns to the table DYNAMIC_STATEMENT_CACHE_TABLE. These columns are for future DB2 use and will be described and used in a future DB2 APAR/PTF: EXPANSION_REASON CHAR(2) NOT NULL WITH DEFAULT ... STAT_ACC_ELAP BIGINT NOT NULL WITH DEFAULT STAT_ACC_CPU BIGINT NOT NULL WITH DEFAULT STAT_ACC_ROW BIGINT NOT NULL WITH DEFAULT STAT_ACC_BYTE BIGINT NOT NULL WITH DEFAULT STAT_ACC_1ROW BIGINT NOT NULL WITH DEFAULT STAT_ACC_DB2 BIGINT NOT NULL WITH DEFAULT STAT_ACC_EXEC BIGINT NOT NULL WITH DEFAULT STAT_ACC_WAIT BIGINT NOT NULL WITH DEFAULT ACCEL_OFFLOAD_ELIGIBLE CHAR(1) NOT NULL WITH DEFAULT 'N' ACCELERATOR_NAME VARCHAR(128) WITH DEFAULT NULL
Problem conclusion
Temporary fix
Comments
new function support of dsc for idaa Additional Keywords: IDAAV4R1/K
APAR Information
APAR number
PI22531
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
A10
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
YesSpecatt / New Function
Submitted date
2014-07-22
Closed date
2015-01-13
Last modified date
2015-12-09
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI24359
Modules/Macros
DSNTESC DSNTXTA DSNTXTB DSNXEADW DSNXECL DSNXECLF DSNXECLN DSNXECW DSNXECWA DSNXECWU DSNXEDP DSNXEDSC DSNXEDS1 DSNXEPM DSNXERT DSNXERT2 DSNXEUFP DSNXEUF0 DSNXMIT2 DSNXODML DSNXOD12 DSNXOIN DSNXONZA DSNXONZB DSNXRFF DSNXRFN DSNXRIWS
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RA10 PSY UI24359
UP15/01/29 P F501
Fix is available
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Document Information
Modified date:
09 December 2015