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Request Cache Hits & Misses - comment by carrie

Pierre, Executing queries by themselves will not cause the request cache to be spoiled.  (By "spoiling" I mean selectively removing entries, in contrast to "purging" which removes all or most entries.)...

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Request Cache Hits & Misses - comment by LUCAS

Carrie, by the way, how does the optimizer recognize a "query" as being already in cache from another query being not ? I understand that every query is marked as an entry in the query cache, even...

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Request Cache Hits & Misses - comment by LUCAS

Carrie, After investigation i read some interesting details about Cache management structure in documentation (Teradata SQL Reference). Sorry for questions "in a hurry", Pierre

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Two Levels of Concurrency Control for Load Utilities in Teradata 13.10 -...

Hi Carrier, Could you please help me with what are all the possible cases/scenerios  this "WDOverride" flag got updated as "T" in dbc.dbqlogtbl. 

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Intrepreting DBQL DelayTime in Teradata 13.10 - comment by kishorem

Hi Carrie, Could you please help me , how the Teradata viewpoint is calculating "Responding state" time. Can we do it from the dbql/some other source  after completing  the query/request ?

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Statistics Collection Recommendations – Teradata Database 14.10 - comment by...

Hi Carrie, Can you share any new recommendations for Stats with Version 15.  Thanks Manjeeth

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Request Cache Hits & Misses - comment by carrie

Pierre,  YOUR QUESTION:  How does the optimizer recognize a "query" as being already in cache from another query being not ?  Strictly speaking it is request (a request can consist of multiple...

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Two Levels of Concurrency Control for Load Utilities in Teradata 13.10 -...

For load utilities all work between the BEGIN WORKLOAD and END WORKLOAD are considered to be a Unit Of Work (UOW).  When a BEGIN WORKLOAD is received the UOW is defined and classified. All work within...

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Intrepreting DBQL DelayTime in Teradata 13.10 - comment by carrie

I am not familiar with "Responding State" as it appears in Viewpoint.  You would have to ask that question of someone who has more extensive knowledge of Viewpoint porlets.  In DBQogTbl, starting in...

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Statistics Collection Recommendations – Teradata Database 14.10 - comment by...

I don't have a list of DBC stats recommendations focused especially on the 15.0 release.  What you can do is use the recommendations in the  blog posting for collecting stats on the dictionary tables...

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Recommended Dictionary Statistics to Collect in Teradata 14.0 - comment by...

Hi,  1 question. If we collect dictionary stats, will this collect stats impact the application performance in anyway? Do we need to test the application as a whole before implementing collection of...

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Statistics collection recommendations – Teradata 14.0 - comment by arpitsinha

Hi Carrie,  One of my table having 2,132,426,728 rows in a column which is also UPI for this table. It is on TD 14.10. While collecting stats on this table(Column) it is taking ~14K CPUs without using...

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Using IOTAs to Determine the I/O Utilization of Your Workloads - comment by...

Hi  carrie , do we have something simmilar for database version v 14.0 where we can look at the IO usage

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Recommended Dictionary Statistics to Collect in Teradata 14.0 - comment by...

Atul,  Dictionary stats usually take only a couple of minutes to collect, as the tables tend to be small.  And you do not need to recollect them very often.  I am not aware of any issues around...

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Statistics collection recommendations – Teradata 14.0 - comment by carrie

Arpit,  USING SAMPLE specified on a collect statistics statement does not necessarily result in sampling taking place.   It means you are letting the optimizer decide whether or not to sample.   You...

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Statistics collection recommendations – Teradata 14.0 - comment by arpitsinha

Thanks Carrie; Got the point.  Actually our client was collecting full stats on this column(s) and I saw the opportunity to suggest them this feature. Next time onwards first I will read the explain...

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Using IOTAs to Determine the I/O Utilization of Your Workloads - comment by...

In the Workload Management Capacity on Demand orange book, there is an I/O throughput metric that can be used to assess I/O usage by workload.  See section 5.2 of this orange book.   Essentially there...

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Statistics collection recommendations – Teradata 14.0 - comment by carrie

2% sampling should fine fine for a UPI column.  Sampling at low percentages is fairly accurate for any column that is unique or nearly-unique.  Unfortunately, there is no way I know of to derive the...

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Teradata Basics: Parallelism - comment by mukuljain015

Hey Carrie, Thanks for putting useful contents in the blog. my question is: how to disable throttle on TD-14.10 sles-11 System. I'm trying to deactivate throttle by several means but it's not working....

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Automatic Throttles in Teradata 14.0 and 14.10 - comment by TERABOY_DBA

Hi Carrie, I am supporting a newly upgraded 2650 appliance from 13.10 to 14.10. There is already a ruleset defined on the system but I could not view it because it says:This ruleset's version 1310 is...

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