Release Notes
Abstract
This document describes enhancements and fixes in IBM Db2 Analytics Accelerator for z/OS Version 5.1.0, maintenance level PTF-9 and maintenance level PTF-9 Update 1
Content
Prerequisites and Maintenance for IBM DB2 Analytics Accelerator for z/OS, V5.1.
6.1.0.4.20170901-1139
After an installation of V5.1.0 maintenance level PTF-9 (PTF-9 Update 1), 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 maintenance level PTF-9 (PTF-9 Update 1)
APARs fixed
APAR # | APAR description | Comments |
PH31837 | Upon processing of heavy workload out of a sudden both loads and queries may hang. Subsequently the accelerator server restarts. | Issue fixed by new ODBC driver delivered with NPS 7.2.1.10-P2 [Build 5] as part of V5PTF9 |
PH37445 |
Optionally support logon to the IBM DB2 Analytics Accelerator Console using the ssh protocol.
|
Fix is part of PTF UI75279 |
Migration recommendations and considerations
For recommendations and considerations concerning migration to IBM Db2 Analytics Accelerator for z/OS Version 5.1.0 read here.
Known issues
-
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 IBM Db2 Analytics Accelerator for z/OS Version 5.1.0 maintenance level 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:
-Duser.language=en -Duser.country=US
- 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.
Example of high system utilization: 30 parallel load threads with tables having 10 partitionsSolution or workaround- Check the system utilization.
- Adjust the system utilization as needed.
- Retry failed operations and continue.
-
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.
-
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 newlinesSummaryTables cannot be added if their names contain special characters, such as tabs and newline characters.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.
-
ALTER TABLE ALTER PARTITION is not blocked by a partition in PRO State (Db2 V11 only)SummaryA partition can be altered by an ALTER TABLE ALTER PARTITION statement although the partition has been archived by the SYSPROC.ACCEL_ARCHIVE_TABLES stored procedure. Normally, SQLCODE -904 would be returned because the archived partition has been set to the PRO state.Solution or workaroundBecause a read-only partition was changed, a following restore operation will probably fail. The problem has been fixed in Db2 V12.
-
Queries may be failing with message "rsn=4:An unknown internal error occurred"SummaryUnder very high system utilization and an extremely high frequency of thousands of concurrent HTAP queries, some of these queries may fail with message "rsn=4. An unknown internal error occurred".Solution or workaroundRestart the incremental update processes.
-
Replication may fail with message "A SQL exception has occurred. The SQL error code is '1100'. The SQL state is: HY000." (See PH37448)SummaryIn rare circumstances with very high system load it may happen that the Netezza database system temporarily rejects insert/update/delete operations. The issue is accompanied by message "The SQL error code is '1100'. The SQL state is: HY000". The action you have attempted has caused the back end to close the connection.". In this context the CDC capture agent log shows the following messages:CHC0256I (Subscription DWA74QE6 has received an immediate shutdown request), CHC0136I, CHC0123I, CHC0223I, CHC0221I.Replication recovers from this temporary unavailability of the target database by automatically stopping and restarting replication until this succeeds. The overall system therefore recovers completely, no data is lost. Replication continues.Solution or workaroundRestart the incremental update processes.
How to identify tables which should be reloaded after an installation of V5.1.0 maintenance level PTF-9 (PTF-9 Update 1) (only if maintenance 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:
How to store information about accelerated tables in a Db2 for z/OS table
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 determine whether a table must be reloaded.
- Immediately after the upgrade to V5.1.0 PTF-9 (PTF-9 Update 1), 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.
Was this topic helpful?
Document Information
Modified date:
20 July 2022
UID
ibm16444135