42 | 14 Nov 2007 @ 04:01 PST | Database | Reply | Distinct V/s Group By | Please analyse the Explain Plan of both the queries to get more information.I feel the Table could be heavily skewed.Regards,Annal T |
41 | 14 Nov 2007 @ 03:12 PST | Database | Reply | How do I create an index | For Unique SI-- Create Unique Index IndexName (Col1,Col2,...Coln) on TablenameFor Non Unique SI-- Create Index IndexName (Col1,Col2,...Coln) on TablenameRegards,Annal T |
40 | 14 Nov 2007 @ 03:07 PST | Database | Reply | How do I create an index | When you say you have pushed the data to TD i assume it was moved to a TD table.Every table would have a Primary index by default.(Either user defined or automatically assigned)See if the PI column... |
39 | 12 Nov 2007 @ 03:11 PST | Database | Reply | Explain plan | Documents are available at www.Info.teradata.com.Information on Explain is available in several documents.You can start with "SQL Reference - Statement and Transaction Processing" PDfChapter Name :... |
38 | 09 Nov 2007 @ 06:26 PST | Database | Reply | Explain plan | Start with simple queries and try to understand their plans and then play with the query and see the impact on the explain plan. Gradually increase the complexity of the queries and analyse.Regards... |
37 | 09 Nov 2007 @ 06:23 PST | Database | Reply | Explain plan | Hi,There are no quick steps available to understand the explain plan completely.Please go through the documentation for a day or two.I've provided some points which can be a start up for you (Hope ... |
36 | 06 Nov 2007 @ 11:31 PST | Database | Reply | Soft Referential Integrity | Soft RI is just an indication that there is a PK-FK relation between the columns and is not implemented at TD side.But having it would help in cases like Join processing etc.It is expected that thi... |
35 | 05 Nov 2007 @ 11:07 PST | Database | Reply | How to force duplication of the rows from a small table on all AMPs | Collecting stats should help in this case.Generally collecting stats on the small table would help the optimiser realise that the table is actually small and might make it go for duplication.Make s... |
34 | 05 Nov 2007 @ 10:56 PST | Training | Reply | Version 12 certification | Teradata has mentioned that they would start rolling out tests for the next version from Third quarter of 2008. V2R5 exams will also be available in parallel for some time.Regards,Annal T |
33 | 04 Nov 2007 @ 12:24 PST | Database | Reply | How to force duplication of the rows from a small table on all AMPs | Yes. Doing any manipulations on the index would prevent it from being used.Dieter,Will preventing an index usage result in duplication ?Is there any relation between index usage and join strategy(D... |
32 | 02 Nov 2007 @ 10:52 PDT | Database | Reply | DENSE_RANK | As dieter mentioned its not available in Teradata.Dense_Rank is an ANSI function available in other databases like Oracle.Regards,Annal T |
31 | 02 Nov 2007 @ 05:35 PDT | Database | Reply | DENSE_RANK | The other options are really interesting ways to get Dense_Rank :)Regards,Annal T |
30 | 02 Nov 2007 @ 05:31 PDT | Database | Reply | DENSE_RANK | I'm not sure if the first option would workSELECTe.department_number,dt.rnk AS "DENSE_RANK",e.last_name,e.salary_amountFROM cs_views.employee eJOIN(SELECTsalary_amount,RANK() OVER (ORDER BY salary_... |
29 | 02 Nov 2007 @ 04:21 PDT | Database | Reply | DENSE_RANK | Dense Rank doesnt leave gaps between ranks.For example in normal Ranking operation if two people have same marks, they both would be given the same Rank, say 1.Now the next person would be given Ra... |
28 | 02 Nov 2007 @ 03:58 PDT | Database | Reply | Accessing Partition ID for a Table | Yes. Partition exists from V2R5.But i thought usage of Partition column for purposes like statistics collection etcwas offered to the users only from V2R6.Regards,Annal T |
27 | 31 Oct 2007 @ 02:38 PDT | Database | Reply | Accessing Partition ID for a Table | Whats the Teradata version you are using?I think the system derived column "Partition" is available only from V2R6.1Regards,Annal T |
26 | 30 Oct 2007 @ 07:36 PDT | Database | Reply | Column compression and Table header size | Hi Dieter,Any specific reason for selecting Min(currentperm) and not Max(Currentperm) for that table?Regards,Annal T |
25 | 30 Oct 2007 @ 06:51 PDT | Database | Reply | What is Typical rows per value? | Its done in the same way.In the count(*) option select the maximum one.In the above example you can see that the max rows per value is 5.Here the typical rows per value and max rows per value dont ... |
24 | 30 Oct 2007 @ 06:00 PDT | Database | Topic | Cluster level Archive!!! | Hi,I would like to know about "Cluster Archive" and how it differs from an All-Amp Archive.Regards,Annal T |
23 | 30 Oct 2007 @ 02:23 PDT | Database | Reply | PPI | I think joes explanation was complete and clear.With USI, you hash the usi value and go to the subtable which gives exact location of that record which contains this USI value.I assume the subtable... |
22 | 30 Oct 2007 @ 01:54 PDT | Database | Reply | Column compression and Table header size | I remember seeing in some document that the max size of the compressed values cant exceed 8192 characters.So make sure you dont compress too many values(across columns) which exceeds this size.Rega... |
21 | 30 Oct 2007 @ 01:47 PDT | Database | Reply | What is Typical rows per value? | You can use this value along with "Max rows per value" to see if there are chances of data skew.If those two value differs by a big margin then there are chances of high data skew which might lead ... |
20 | 24 Oct 2007 @ 04:05 PDT | Database | Reply | Name convension problem. | If it says object doesnt exist, try to create a table with the same name again and see what happens ;)Regards,Annal T |
19 | 23 Oct 2007 @ 03:03 PDT | Database | Topic | Doubt on the Index Validation part of the Index Wizard!! | I worked on the Index wizard available in the Demo package and I would like to know how we use the validate index option in real time.It was stated that since we often use the index wizard in the T... |
18 | 23 Oct 2007 @ 02:40 PDT | Database | Topic | Scheduling policies in Priority Scheduler !!! | I would like to know the difference between "Default" and "Immediate" scheudling policies available in Priority Scheduler.Both are used when we dont want a hard ceiling on the resource usage.It was... |