#DateWhereItemComment
1722 Mar 2014 @ 07:45 PDTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsRahul, I don not personally know the reason for this, but this is the way things work. For instance if you concatenate a few fields and one of them is NULL the result is also NULL. This seems con...
1622 Mar 2014 @ 07:44 PDTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsSivakumar, That would makes sense to me if the additional non-PI column did not make any demographic changes, like all rows had the same status value and multi-column stats were on PI+Status. I e...
1503 Dec 2013 @ 08:01 PSTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsIt looks like the link has been unpublished. this is probably due to the fact that in the latest releases of Teradata the multi-column statistics work slightly different now.
1429 Apr 2013 @ 03:46 PDTDatabaseWorkload Toolkit – Part 2 – Analyze Secondary Index UsageObject level logging will populate the dbc.DBQLObjTbl for all object types referenced. You can look for object type IDX (I beleive) to see used indexes. Cross referencing this back to the dbc.index...
1302 Apr 2013 @ 09:59 PDTDatabaseWorkload Toolkit – Part 4 – Compression AnalysisI am not sure what you are asking for here. Either the values are persistent enough (months or more) or they are not, and I would agree to not compress those values. Dave
1217 Mar 2013 @ 11:01 PDTDatabaseWorkload Toolkit – Part 4 – Compression AnalysisAmit, Most of the time the actual demographics of compressed data changes infrequently, i.e Flags continue to have Y/N values. etc. There are two instances that cause clients to re-evaluate the c...
1118 Sep 2011 @ 03:47 PDTDatabaseWorkload Toolkit – Part 4 – Compression AnalysisUsing COMPRESS by itself will compress the NULL values in the column. There is no option to automatically compress all values.
1008 Jan 2011 @ 05:53 PSTDatabaseWorkload Toolkit – Part 4 – Compression AnalysisSecondary Index columns are no problem, but PPI columns are excluded just like PI columns. On a bright note, the VARCHAR restriction is lifted in version 13.10
920 Oct 2010 @ 10:47 PDTDatabaseWorkload Toolkit – Part 2 – Analyze Secondary Index UsageYes, if you enable object level logging, it will capture the indexes that are used in the dbql data. Indexes that are never referenced, are not used. You need to make sure this runs for a sufficien...
828 Aug 2010 @ 11:35 PDTcarrie's blogPenalty Box Over-Population Also agree, great article! I do have a further question. In the days before penalty boxes, we used to use TDQM to identify very bad queries and reject them for analysis by the dbas and develope...
725 Jul 2010 @ 10:11 PDTDatabaseWorkload Toolkit - Part 3 - Statistics AnalysisSorry for the late response. Look at the web link just before the query text for the stats queries. View name is our own, but logic is on web site.
621 Jul 2010 @ 02:27 PDTDatabaseWorkload Toolkit – Part 4 – Compression AnalysisThis is the process I generally see used. Alters are limited, especially if there is any volume to the table. The other thing to remember is that when new table is created any permissions on th...
530 Jun 2010 @ 03:11 PDTToolsEasy Statistics Recommendations - Statistics Wizard FeatureNice overview of the tool and options. I just want to stress to people the importance of the first line in your "when to use" summary. The output of the tool are "recommendations". You must apply,...
427 May 2010 @ 12:18 PDTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsThis is something that I had considered, as a potential second round of identification, using a comparision of multi-column stats values within x% of the single column stats. I believe the idea ...
306 Mar 2010 @ 11:41 PSTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsSo remember, the premise here is that if the help stats number is the same for the first column (col1) as it is for the combination of columns(col1-col4) then that is a "candidate" for removal. In ...
201 Feb 2010 @ 03:24 PSTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsFirst, we are not really looking at PI's here, just the first field of a Multi Column statistics combination. That given, yes, in a nutshell we are saying that if the values for the first field ar...
103 Dec 2009 @ 10:07 PSTDatabaseRemoving Multi-Column Statistics – A Process for Identification of Redundant StatisticsGlad you like it. And I sympathize; don't know how many times I have done sometihing, only to find out someone else had a script or process :)