#DateWhereItemComment
27016 May 2013 @ 07:37 PDTcarrie's blogHow to set a System-Level CPU limit for Capacity-on-DemandSuahil,   If you are talking about PM COD (platform metering COD), then DBQL seconds to perform the same query should go down somewhat-proportionately with the change in percentage of PM COD...
26914 May 2013 @ 04:20 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0Adel, On your first question: I see your point, however there is no functionality to allow you to sample on only specific AMPs.  All AMPs will be sampled at the same percent.  &nbs...
26803 May 2013 @ 02:27 PDTDatabaseStatistics Collection Recommendations for Teradata 12Extrapolation for the 12.0 and the 13.0 releases is discussed in an earlier blog posting of mine here on Developer Exchange.  It is titled:   Why collect PARTITION statistics on Non-Par...
26701 May 2013 @ 10:37 PDTcarrie's blogUsing the ResUsageSAWT table to Monitor AMP Worker TasksMuhammad,   It is not generally recommended to increase the number of AMP worker tasks per AMP.   Usually it only makes sense if there are platform resources that cannot be used an...
26629 Apr 2013 @ 08:20 PDTDatabaseStatistics Collection Recommendations for Teradata 12Amit,   I don't know of any query that can identify which multicolumn stats are greater than 16 bytes, although its possible someone has come up with one.   However, just becau...
26529 Apr 2013 @ 08:16 PDTcarrie's blogFlow Control and Spawned WorkThe message queue is not maintained using AMP worker tasks.  A combination of system services and event-driven PDE internal processes do that work. Thanks, -Carrie
26429 Apr 2013 @ 08:11 PDTDatabaseStatistics Collection Recommendations for Teradata 12On the question of dropping multicolumn stats from Smarak0604: Question a:   Yes, that is true.   If most of the time the value in a leading larger varchar is 16 bytes or less,...
26329 Apr 2013 @ 08:08 PDTDatabaseStatistics Collection Recommendations for Teradata 12Amit, I have an earlier posting on when to collect statistics on dictionary tables.    http://developer.teradata.com/blog/carrie/2010/05/if-you-re-not-collecting-statistics-on-your-dic...
26229 Apr 2013 @ 08:06 PDTcarrie's blogAre AMP Worker Tasks used by FastExport in Response Mode?Idle sessions are sessions that are between database requests.  They do not have any active work that could be holding AMP worker tasks on the AMPs.    And you are correct that the...
26124 Apr 2013 @ 02:19 PDTcarrie's blogDatabase Tasks that Run on the Parsing Engine Yes, the limit of 120 sessions per parsing engine is standard.  I don't know of any sites that have attempted to raise that limit.  Most sites that require a larger number of sessions...
26017 Apr 2013 @ 04:57 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0Hi Michael,   I agree with you that decisions about which stats to collect and how often are challenging today.  As you are probably aware, there is increasing attention being paid to e...
25916 Apr 2013 @ 03:27 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0trustngs-   1.) You can get the number of distinct values in a NUSI subtable by doing a HELP INDEX table-name.   But information as to the exact number of rows across all AMPs and ...
25816 Apr 2013 @ 03:26 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0gsasubi-   I am not able to answer your question on JAVA apps and macros.  Please post this question on one of the Teradata Q&A Forums if you want to get it out to a broader au...
25716 Apr 2013 @ 11:02 PDTcarrie's blogHow to Calculate Your Max Number of Usable AMP Worker TasksTactical query performance may be improved by specifying a reserve count for expedited queries.  It will depend on whether or not the system is short on AWTs.  If there is no shortage of ...
25616 Apr 2013 @ 11:00 PDTcarrie's blogFlow Control and Spawned Work(a).  Flow control may or may not be restricted to MsgWorkNew work types.   I was using "new" in the generic sense in the text above.  No additional work wil...
25512 Apr 2013 @ 08:39 PDTcarrie's blogAutomated Demotions on the Appliance: What are Query Milestones?Hi Phil,   Sorry, CPU limits on allocation groups are not available on the appliance platform.  The closest thing to that is the query milestones described in this posting. &n...
25412 Apr 2013 @ 08:34 PDTcarrie's blogEliminating Unplanned Delays Within Load Utility JobsFor tenacity to be able to get involved, the load job has to have been rejected by the database and an error message returned to the client indicating that.  Since you are not rejec...
25310 Apr 2013 @ 08:32 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0I'm not sure why your explain text doesn't give you estimated rows, but when I tried your SQL it worked for me.  Make sure you have collected stats on that column.  EXPLAIN SELEC...
25209 Apr 2013 @ 10:35 PDTDatabaseTo Peek or Not to Peek, That is the QuestionIf the cache flag field in DBQLogTbl is blank, it means that the query is NOT using a cached plan and had to go through parsing and optimization.  Only the value of "T" means th...
25102 Apr 2013 @ 04:39 PDTDatabaseTo Peek or Not to Peek, That is the QuestionThe first two entries are not cached because the SQL does not contain parameterized SQL.   As it says in the text below the table you are referring to:  "What this example is illus...
25025 Mar 2013 @ 02:55 PDTcarrie's blogUtility Throttles – You Won’t Regret It!For utility throttles you can go to the Viewpoint  Query Monitor portlet.  Under Select Report, choose By Utility and you get a list of active utility throttles and their limits.   ...
24919 Mar 2013 @ 01:52 PDTcarrie's blogStatistics collection recommendations – Teradata 14.0Hi Rich,   Once you have defined all the stats on a table separately, you can recollect at the table level with one SQL command.  This will re-collect everything already defined against...
24819 Mar 2013 @ 01:51 PDTDatabaseTo Peek or Not to Peek, That is the QuestionIf you don't want generic plans to be used, the easiest thing to do is to remove the parameterization from the request.  That will ensure you always get a specific plan.    ...
24719 Mar 2013 @ 01:49 PDTcarrie's blogNew opportunities for statistics collection in Teradata 14.0I am not familiar with the error mentioned above.  If you are still not sure what is happening, consider opening an incident with the support center.    Thanks, -Carrie
24619 Mar 2013 @ 01:47 PDTcarrie's blogNew opportunities for statistics collection in Teradata 14.0Response to Samyyy's three questions from 3 days ago: #1:  I am not sure I am understanding what you are saying when you say:  "I have tried defining stats using new synta...

Pages