IBM DB2 Analytics Accelerator for z/OS Version 5.1.0 maintenance level PTF-3: Release Notes
This document describes enhancements and fixes in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0, maintenance level PTF-3
After an installation of V5.1.0 PTF-3, the former method of data organization is re-activated. If the switch back to the former data organization fails, the following message is written to the z/OS system log (SYSLOG) of the LPAR in which the DB2 subsystem or group is located:
How to identify tables that should be reloaded after an installation of V5.1.0 PTF-3
Please find information about new functions here.
Snippet-Processing Units (SPUs) running out of resourcesAffected usersAll users of IBM DB2 Analytics Accelerator for z/OSProblem descriptionAccelerator goes offlineProblem summaryThis problem occurs if queries that are routed to an accelerator contain numerous recursive REPLACE() calls.Problem conclusionThe problem has been fixed.
Accelerator-shadow tables become inconsistent with empty tables in DB2 for z/OSAffected usersAll users of IBM DB2 Analytics Accelerator for z/OSProblem descriptionAn affected accelerator-shadow table contains more rows than the DB2 table.Problem summaryThis problem occurs during a full table reload, when you reload a segmented table or all partitions of a partitioned table.
Problem conclusionThis PTF fixes the problem described in the following tech note: Data inconsistencies between accelerator-shadow tables and empty DB2 for z/OS tables
- A DB2 for z/OS table contains data.
- A corresponding accelerator-shadow table exists and you have loaded it.
- All data is deleted from the table in DB2 for z/OS.
- The now empty table is reloaded on the accelerator. At this point, the DB2 for z/OS is empty, but the accelerator-shadow table might still contain the data loaded in step 2.
Migration recommendations and considerations
For recommendations and considerations concerning migration to IBM DB2 Analytics Accelerator for z/OS Version 5.1.0 read here.
IBM Netezza AnalyticsFor known issues with the IBM Netezza Analytics stored procedure package in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0, see:
Encryption of Data in MotionFor known issues with the network traffic encryption feature (encryption of data in motion) in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0, see:
Transfer of software update packages from IBM DB2 Analytics Accelerator Studio not possibleSummaryIBM Analytics Accelerator Studio does not allow users to transfer packages. A message hints at the fact that a newer version is already installed on the server. If the locale in the IBM Analytics Accelerator Data Studio is set to a value different from English or German, the transfer of software update packages might be blocked in rare cases.Solution or workaroundThe problem has been fixed with the stored procedures of version 5.1.0 PTF-1. If you run the software transfer with a previous version of the stored procedures, use the following workaround:
- Use US English as the locale for IBM DB2 Analytics Accelerator Studio.
- On a Windows system, add '-nl en_US' (without the quotes) to the start command that you find in the properties of the shortcut that launches the application ("Target" field on "Shortcut" tab).
On a Linux system, open the eclipse.ini file and add the following line:
- Save and close the file. Then start the application.
If the system utilization is very high, the accelerator might restart automatically to recover from the overload situationSummaryThe accelerator goes online again after the recovery. Processes that were ended prematurely by the restart, such as load jobs or queries, must be restarted.Solution or workaround
- Check the system utilization.
- Adjust the system utilization as needed.
- Retry failed operations and continue.
Load operations stall if the system utilization is very highSummaryOccasionally, load jobs might end abnormally if the system utilization is very high.Solution or workaroundCancel and restart the load operation.
The execution of an INSERT INTO ... SELECT ... FROM statement in an in-database transformation job might failSummaryIn rare situations, INSERT INTO ... SELECT ... FROM statements in in-database transformation jobs can fail if the system utilization is very high and many processes are run in parallel.Solution or workaroundThis is an indication that the system limits were reached. Check the system utilization and adjust it to the capacity of the system.
Incremental update processing might stop and restart if the system utilization is very high (many parallel load and query operations). This is indicated by according console messagesSummaryIf the system utilization is very high, with many processes running in parallel, the processing of incremental updates might stop. Processing resumes after some time and stalled operations are recovered automatically. If "continuous incremental updates" are enabled, tables that are being loaded at the time of the interruption go into the "suspended" state. You must reload such tables to get them back into the incremental update processing queue.Solution or workaroundThis is an indication that the system limits were reached. Check the system utilization and adjust it to the capacity of the system.
High system utilization causes slower performance of IBM DB2 Analytics Accelerator tasksSummaryMaintenance tasks might take longer than expected if the system utilization is high.Solution or workaroundIf the problem persists, restart the Netezza Platform Software (NPS) from the IBM DB2 Analytics Accelerator Console.
Queries might fail if system utilization is highSummaryA high system utilization might cause queries to fail occasionally with errors, such as ‘NZ IO error‘ or ‘SQL code = -904 00E7000E Bad data’ .Solution or workaroundThe system continues to operate. Subsequent queries succeed.
A reload of a table set with many tables failsSummaryA reload of a table set with thousands of tables might fail sporadically.Solution or workaroundSplit the table sets to be reloaded into smaller units and retry the operation.
Load operation aborts with SIGABEND if the system utilization is very highSummaryOccasionally, a load operation might end abnormally if the system utilization is very high.Solution or workaroundRestart the load operation.
Misleading warnings of type 'DSNX881I -DI11 2001 W [...] SQL statement with task ID xxxxxxxx is running for more than xxxxxx seconds'SummaryUnder rare circumstances, a query might be continually reported as long-running, even though it was ended by a network outage or by a connection closure through the client application. These messages do not indicate that query processing is impacted in any way. The system stays operational and subsequent queries will run as expected.Solution or workaroundThe continual reporting of long-running tasks in DSNX88I messages stops after a restart of the accelerator. You can restart an accelerator from the IBM DB2 Analytics Accelerator Console.
Insertion of integer and decimal values causes failure of IDT jobsSummaryThe insertion of integer and decimal values by an INSERT INTO ... VALUES statement might cause a failure of in-database transformation (IDT) jobs.
For example, the following statement failed during tests:
CREATE TABLE T1 (CDEC51 DECIMAL(5,1)) IN ACCELERATOR XYZ;
INSERT INTO T1(CDEC51) VALUES(77247.04-69993);
Symptoms: SQL codes like the following are returned:
SQLCODE = -802, SQLSTATE = 22003, DATA EXCEPTION FROM IBM DB2 Analytics Accelerator TOKENS OVERFLOW ACCELERATOR NUMERIC DATA...Solution or workaroundUse only decimal values instead of a mixture of integer and decimal values. The following statement, for example, will be successful:
INSERT INTO T1(CDEC51) VALUES(77247.04-69993.0)
Tables cannot be added if their names contain special characters, such as tabs and blanksSummaryTables cannot be added if their names contain special characters, such as tabs and blanks.Solution or workaroundFix will be delivered in a later release.
Large number of accelerator-shadow tables might extend time needed to activate incremental updatesSummaryIf there is a large number of tables on an accelerator, that is, more than 30000 the activation of incremental updates for these tables might take longer. In this context, it does not matter whether the tables have already been enabled. The extra time needed is relevant if the number of table activations in one request exceeds 10 because this will lead to a premature end of the operation, which in turn leads to an automatic disablement of incremental updates for those tables. You must re-enable and reload such tables.Solution or workaroundReduce the number of tables that are activated in a single batch job to less than ten (<10).
If the system utilization is high, load operations might fail with a message "Failed to start child transaction in session " -LocksharedObjectWait: LockAcquire failed".SummaryUnder a high system load, load operations might fail with a message "Failed to start child transaction in session " -LocksharedObjectWait: LockAcquire failed".Solution or workaroundRetry the load operation.
How to identify tables which should be reloaded after an installation of V5.1.0 PTF-3 (only if product level is "V5.1.0 GA" or "V5.1.0 PTF-1", without hot fix UI37271)
- Use the sample code (for a stored procedure) in the following technote:
to retrieve information about your accelerator-shadow tables. This information will be stored in a temporary DB2 table.
- Run a simple SQL query against the replicationStatus and the lastLoadTimestamp columns of this temporary table to identify tables that must be reloaded. Follow the diagram at the end of this note to dertermine whether a table must be reloaded.
- Immediately after the upgrade to V5.1.0 PTF-3, an automatic conversion of data structures takes place.
- Depending on the total amount of data to be converted, this might take more than 1 hour, during which the Netezza Platform Software (NPS) will be in the "Initializing" state. That is, the NPS cannot process requests.
Support for DB2 12 for z/OS
Please find known issues here.
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