#DateWhereItemComment
7017 May 2011 @ 08:30 PDTcarrie's blogTwo Levels of Concurrency Control for Load Utilities in Teradata 13.10Suresh, The answer is yes and no. You still have a limit of 30 for the total number of load job utilties that are running at the same time. And you also have a limit on the number of AMP wor...
6921 Apr 2011 @ 08:41 PDTcarrie's blogTwo Levels of Concurrency Control for Load Utilities in Teradata 13.10Hi Emilwu, While you are correct that the workload throttle does not have the option to limit which databases or tables are under its control, the classification criteria for the workload itself...
6819 Apr 2011 @ 03:06 PDTcarrie's blogTwo Levels of Concurrency Control for Load Utilities in Teradata 13.10Hi YB. Thank you for your interesting questions. As for question 1, you can define utility throttles and select the reject option if you wish. This will cause any load job that exceeds the t...
6712 Apr 2011 @ 08:32 PDTcarrie's blogTips on using Sampled StatsAyush, Diagnostic HELPSTATs results in a list of all possible statistics for a given request. Often it provides you with more choices than you will benefit from. It is usually not recommended ...
6628 Mar 2011 @ 12:01 PDTDatabaseStatistics Collection Recommendations for Teradata 12Sorry, Toad, I totally missed your earlier comment. Yes, that looks good in terms of stats to collect on, with one exception. If this is a single-level PPI table and the partitioning colums...
6528 Mar 2011 @ 11:57 PDTDatabaseStatistics Collection Recommendations for Teradata 12Hi Abdul, Data is retrieved from a join index the same as from a base table, either using primary index access, or using partition elimination (if PPI has been defined) or doing a table scan. A...
6428 Mar 2011 @ 11:48 PDTcarrie's blogHow to set a System-Level CPU limit for Capacity-on-DemandHi Ian, I'm not aware of any lower limit on where you set a system-level CPU limit. The thing to keep in mind is that CPU is only one of the critical resources on your platform. There is a...
6318 Feb 2011 @ 03:35 PSTcarrie's blogPenalty Box Over-Population Khalid, Yes, what you are describing is certainly an option. Some people prefer to add a CPU limit onto a low-weighted allocation group because their system is generally quite busy, and they ha...
6227 Jan 2011 @ 08:48 PSTcarrie's blogHow to Calculate Your Max Number of Usable AMP Worker TasksSetting MaxLoadAWT to 48 does not hold back any AWTs in reserve to only be used for load jobs. What it does is prevent new load jobs from starting up if they would cause that limit of 48 to be ex...
6117 Jan 2011 @ 09:09 PSTcarrie's blogConverting CPU Seconds, Old Node Type to New Node TypeThe number CPUs (8 cores) and the CPU power per node is identical on the 5600H and the 2580 platforms. So your CPU seconds should be worth the same value across node types: One CPU second on the ...
6013 Dec 2010 @ 04:05 PSTcarrie's blogUtility Throttles – You Won’t Regret It!Monisiqbal, You can use TDWM, with the throttles category enabled, and then define utility throttles. There is some information on this in the TDWM manual. The screens in TDWM are pretty easy ...
5913 Dec 2010 @ 04:00 PSTcarrie's blogUtility Throttles – You Won’t Regret It!Rich, Sorry for the delayed response. I am just now seeing this comment of your. I don't think I can make a general recommendations about utility concurrency, because what is right for ...
5813 Dec 2010 @ 03:38 PSTcarrie's blogHow to Calculate Your Max Number of Usable AMP Worker TasksBasically, user-initiated work primarily uses Work00 (aka WorkNew) and Work01 work types. A step coming directly from the dispatcher is always a Work00 type. Spawned work, such as the receiver ...
5708 Dec 2010 @ 02:15 PSTcarrie's blogIf You’re Not Collecting Statistics on Your Dictionary Tables, Do It. Now.Somnath, Take a look at an article I co-authored that is also here on DevX titled Statistics Collection Recommendations for Teradata 12. That might help you getter sense of some good practices ...
5608 Dec 2010 @ 02:05 PSTcarrie's blogHow to Calculate Your Max Number of Usable AMP Worker TasksYB, There is no value in increasing the number of AMP worker tasks per AMP if your platform resources are already maxed out. If you are at 100% CPU utilitization, then there will be no additio...
5507 Dec 2010 @ 04:31 PSTcarrie's blogConverting CPU Seconds, Old Node Type to New Node TypeHi TeraAbraham, Yes, you are correct. That is a good point to mention. But let me add that it might be difficult to observe this as precisely as your numbers indicate, because the work be...
5419 Oct 2010 @ 11:09 PDTcarrie's blogPenalty Box Over-Population Thank you for the comments, Vinay. I can't argue with your approach, as I've been some sites save a non-trivial percent of their platform CPU by being willing to reject and/or abort badly-written...
5330 Sep 2010 @ 09:46 PDTcarrie's blogPenalty Box Over-Population Rick, I agree with your points. Thanks for adding them into the discussion. -Carrie
5227 Sep 2010 @ 10:26 PDTDatabaseTo Peek or Not to Peek, That is the QuestionNon-parameterized SQL will not generate a generic plan, re-usable and will not undergo peeking. That is because there are no values to peek at unless parameterized SQL has been used. Non-para...
5127 Sep 2010 @ 10:23 PDTcarrie's blogIf You’re Not Collecting Statistics on Your Dictionary Tables, Do It. Now.Naresh, You can view locking conflicts by means us two different utilities: Lock Disp and/or Locking Logger. Both are described in the Utilities Volume 2 manual, G- S. Thanks, -Carrie
5022 Sep 2010 @ 09:29 PDTcarrie's blogCPU Limits at Multiple LevelsTo get CPU utilization, you can execute the resnode macro and look at the CPU Bsy % column. Or use SQL like this against the ResUsageSPMA table: sel ,sum(CPUUServ + CPUUExec) /sum(spma.secs*sp...
4921 Sep 2010 @ 08:21 PDTDatabaseSkew-Sensitivity in the Optimizer: New in Teradata 12In response to Chusa01... To see the detail inside the histogram you issue this command: HELP STATISTICS table-name COLUMN column-name; You must have some access right (any access right) o...
4821 Sep 2010 @ 08:19 PDTDatabaseSkew-Sensitivity in the Optimizer: New in Teradata 12In response to Quonos... I don't know of any method of forcing a table duplication plan that is different from what the optimizer produces. The key demographics used by the optimizer come fro...
4717 Sep 2010 @ 08:50 PDTDatabaseAll-AMP Random AMP Sampling? Sure, Why Not!Hi Keith, The COLLECT STATISTICS statement will always engage all AMPs, whether or not USING SAMPLE has been specified. If USING SAMPLE is executed and the default 2% sampling rate is used, th...
4615 Sep 2010 @ 01:44 PDTDatabaseStatistics Collection Recommendations for Teradata 12Hi Bob, You may use sampled statistics on primary indexes. In fact if the PI is unique, it's a recommended approach, because sampling will always be pretty accurate with unique data. If it's n...

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