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IBM DB2 Analytics Accelerator for z/OS Version 5.1.0 maintenance level PTF-5: Release Notes

Release Notes


Abstract

This document describes enhancements and fixes in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0, maintenance level PTF-5

Content



Attention:

Depending on the DB2 version you are using the following DB2-PTFs must be installed:


DB2 Version 10: PTF UI48441 (APAR PI76645)
DB2 Version 11: PTF UI48442 (APAR PI76645)
DB2 Version 12: PTF UI48621 (APAR PI82739)


The new federation feature is only supported with DB2 Version 11. If you plan to use it, you must also install the following DB2-PTF:
DB2 Version 11: PTF UI48595 (APAR PI77826)

The minimum required version of IBM DB2 Analytics Accelerator Studio for this maintenance level is:
6.1.3.201706282249



We recommend an upgrade of the accelerator server component of this maintenance level for customers running V5.1.0 maintenance level GA or V5.1.0 maintenance level PTF-1 (UI35012, which was set PE). Customers who already have installed V5.1.0 maintenance level PTF-2 or maintenance level PTF-3 are not affected.

With V5.1.0. GA and V5.1.0. PTF-1, a new way of data organization was introduced. The new organization has the potential to speed up the insertion of small chunks of data which are typical for incremental updates. In rare situations, with huge table sizes, this new way of organizing data might lead to different query results returned by DB2 for z/OS and the accelerator. You can avoid this problem by switching back to the former way of data organization.

After an installation of V5.1.0 maintenance level PTF-5, 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:
DSNX881I - <SSID> W 2004 ... Not all zone map records are consistent with the expected layout
For further information regarding the structure of DSNX881I messages see:

Structure of DSNX881I Messages.

This is a temporary fix. The problem will be finally fixed with an upcoming release of the Netezza Platform Software (NPS). This NPS release will be certified for use with IBM DB2 Analytics Accelerator for z/OS.
Important: To make sure that all inconsistent data is removed from the accelerator, reload the potentially affected tables as decribed here:
How to identify tables that should be reloaded after an installation of V5.1.0 maintenance level PTF-5


What's new

Please find information about new functions here.



Solved problems

  1. Stored procedure SYSPROC.ACCEL_GET_TABLES_DETAILS returns error message AQT10301E
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    SYSPROC.ACCEL_GET_TABLES_DETAILS fails with an error message similar to: AQT10301E - An error occurred in the DSNWLIR service of your database management system (DBMS). The return code is 8. The reason code is 0x00E60820. Additional diagnostic information: 'error in DB2 command '-ACCESS DB(POULÅÅ92) SP(POULÅÅ1S) MODE(STATS)': DSN9027I -DB2A KEYWORD 'DB' PARAMETER(S) MUST BE ALPHAMERIC DSN9027I -DB2A KEYWORD 'SP' PARAMETER(S) MUST BE ALPHAMERIC DSN9023I -DB2A DSN9SCND '-ACCESS DB' ABNORMAL COMPLETION
    Problem summary
    The problem occurs if database or tablespace names for an accelerated table contain characters whose codepoints are different in the 1047 CCSID and the EBCDIC SBCS CCSID set in DSNHDECP.
    Problem conclusion
    The problem has been fixed.
  2. DSNR035I message in console log while running a load job
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    Message DSNR035I appears on the console while loading data into accelerator-shadow tables. The affected object is DSNAQT.UNLOADIDS.
    Problem summary
    The loading of accelerator-shadow tables requires a unique DB2 sequence number. A lock is held on the corresponding sequence during the load, which causes the DSNR035I messages on the console.
    Problem conclusion
    The problem has been fixed.
  3. Discrepancy between 'DISK STORAGE IN USE' values
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    The monitoring section in IBM DB2 Analytics Accelerator Studio and the -DISPLAY ACCEL command in DB2 might display different values for 'DISK STORAGE IN USE'. The discrepancy between the values amounts up to 10%.
    Problem summary
    Reported values for the use of disk space differ. The difference amounts up to 10 percent.
    Problem conclusion
    The problem has been fixed.
  4. Load jobs fail with out-of-memory error condition
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    The load performance decreases because wrongly triggered reorganization jobs reserve memory blocks. In the worst case, out-of-memory errors occur during load.
    Problem summary
    The problem occurs when users reload accelerator-shadow tables.
    Problem conclusion
    Load jobs fail less frequently with out-of-memory error condition.
  5. Load jobs fail with message 'Missing management subscription for subscription XXX.'
    Affected users
    All users of the incremental update function in IBM DB2 Analytics Accelerator for z/OS Version 4.1.0 PTF-6 and higher
    Problem description
    A table load fails with the message 'Missing management subscription for subscription XXX'
    Problem summary
    If 'continuous incremental updates' are enabled, the loading incrementally updated tables might fail.
    Problem conclusion
    The problem has been fixed. An alternative workaround is to disable 'continuous incremental updates', load the tables, and re-enable the feature.
  6. Slow load performance on growth-on-demand systems with limited resources
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    Load jobs do not perform as fast as on systems without resource limits
    Problem summary
    The problem occurs if system resources were limited by the option 'Set a system-wide resource limit' on the IBM DB2 Analytics Accelerator Console.
    Problem conclusion
    The problem has been fixed.
  7. Current timestamp discrepancy between DB2 and Accelerator (APAR PI85560)
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    If a query which uses the special register "current timestamp" is being offloaded to the accelerator, the timestamp returned might be different from DB2 when the DB2 local timezone has an offset to the UTC timezone (e.g. UTC-7). The offset is being calculated into the opposite direction.
    Problem conclusion
    The problem has been fixed with PTF UI49630.
  8. Multi-Row inserts into Accelerator-Only tables fail with SQL0904N (APAR PI85615)
    Affected users
    All users of IBM DB2 Analytics Accelerator for z/OS Version 5.1.0
    Problem description
    If a column contains a new line character, chr(10) or chr(13), the insert statement fails with the following error: <TASK_..-WRITER_1_*_> SEVERE: WRT_8229 Database errors occurred: IBM CLI Driver DB2 SQL0904N Unsuccessful execution caused by an unavailable resource. Reason code: " External Table : count of bad input rows reached maxerrors limit", type of resource: "", and resource name: "". SQLSTATE=57011 {Row=1} sqlstate = 57011 Database driver error...
    Problem conclusion
    The problem has been fixed with PTF UI49630.

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

  1. IBM Netezza Analytics
    For known issues with the IBM Netezza Analytics stored procedure package in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0, see:

    Known issues with IBM Netezza Analytics for System z for IBM DB2 Analytics Accelerator for z/OS Version 5.1.0

  2. Encryption of Data in Motion
    For 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:

    Known Issues with Encryption of Data in Motion in IBM DB2 Analytics Accelerator for z/OS Version 5.1.0

  3. Transfer of software update packages from IBM DB2 Analytics Accelerator Studio not possible
    Summary
    IBM 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 workaround
    The 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:
    1. Use US English as the locale for IBM DB2 Analytics Accelerator Studio.
    2. 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

    3. Save and close the file. Then start the application.
  4. If the system utilization is very high, the accelerator might restart automatically to recover from the overload situation
    Summary
    The 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 partitions
    Solution or workaround
    1. Check the system utilization.
    2. Adjust the system utilization as needed.
    3. Retry failed operations and continue.
  5. The execution of an INSERT INTO ... SELECT ... FROM statement in an in-database transformation job might fail
    Summary
    In 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 workaround
    This is an indication that the system limits were reached. Check the system utilization and adjust it to the capacity of the system.
  6. 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 messages
    Summary
    If 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 workaround
    This is an indication that the system limits were reached. Check the system utilization and adjust it to the capacity of the system.
  7. Insertion of integer and decimal values causes failure of IDT jobs
    Summary
    The 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 workaround
    Use 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)

  8. Tables cannot be added if their names contain special characters, such as tabs and newlines
    Summary
    Tables cannot be added if their names contain special characters, such as tabs and newline characters.
    Solution or workaround
    Fix will be delivered in a later release.
  9. Large number of accelerator-shadow tables might extend time needed to activate incremental updates
    Summary
    If 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 workaround
    Reduce the number of tables that are activated in a single batch job to less than ten (<10).
  10. If the system utilization is high, load operations might fail with a message "Failed to start child transaction in session " -LocksharedObjectWait: LockAcquire failed".
    Summary
    Under a high system load, load operations might fail with a message "Failed to start child transaction in session " -LocksharedObjectWait: LockAcquire failed".
    Solution or workaround
    Retry the load operation.
  11. ALTER TABLE ALTER PARTITION is not blocked by a partition in PRO State (DB2 V11 only)
    Summary
    A 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 workaround
    Because a read-only partition was changed, a following restore operation will probably fail. The problem has been fixed in DB2 V12.


How to identify tables which should be reloaded after an installation of V5.1.0 maintenance level PTF-5 (only if maintenance level is "V5.1.0 GA" or "V5.1.0 PTF-1", without hot fix UI37271)

STEP 1: Identify the tables which could be affected
  • 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.

STEP 2: For all identified tables, disable query acceleration. For more information, see Disabling query acceleration for tables

STEP 3: Install V5.1.0 PTF-5.

STEP 4: Automatic conversion
  • Immediately after the upgrade to V5.1.0 PTF-5, 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.
STEP 5: Reloading tables
Within the first hour after installation of the new accelerator server code, you might see a "DSNX881I - W 2004 ... Not all zone map records are consistent with the expected layout." message in the SYSLOG, which reports conversion failures. This is normal if the amount of data to be converted is high. The conversion failures are caused by a timeout mechanism. Check the SYSLOG one hour after the installation of the accelerator server. If you see zero or at most one DSNX88I-2004 message, the conversion has finished successfully and you can start with the full-table reload of the identified tables. If you see more than one DSNX88I-2004 message, check the SYSLOG again after 7 hours. If further messages show up, you might have a real conversion problem. In this case, contact IBM support.
STEP 6: Enable query acceleration after a full table reload. For more information, see Enabling tables for query acceleration
Click on the image to enlarge it

Support for DB2 12 for z/OS

Please find known issues here.

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Document Information

Modified date:
08 August 2018

UID

swg27050024