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.)...
View ArticleRequest 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...
View ArticleRequest 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
View ArticleTwo 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.
View ArticleIntrepreting 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 ?
View ArticleStatistics Collection Recommendations – Teradata Database 14.10 - comment by...
Hi Carrie, Can you share any new recommendations for Stats with Version 15. Thanks Manjeeth
View ArticleRequest 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...
View ArticleTwo 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...
View ArticleIntrepreting 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...
View ArticleStatistics 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...
View ArticleRecommended 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...
View ArticleStatistics 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...
View ArticleUsing 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
View ArticleRecommended 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...
View ArticleStatistics 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...
View ArticleStatistics 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...
View ArticleUsing 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...
View ArticleStatistics 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...
View ArticleTeradata 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....
View ArticleAutomatic 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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