I have a table with emp id, emp name, dept id and sal where
dept id is NUSI. SEL * FROM EMP WHERE DEPTID = 100. Can any
one explain how it will fetch the record.
- 4 Answers
- 8747 Views
- I also Faced
- E-Mail Answers
Answer Posted / ajain
Whenever NUSI is created, subtable will be created for each AMP's with the fields rowid and secondary index value.For NUSI ,subtable will be AMP local ie it will be having the records which are specific to the particular AMP.
When someone queries with the NUSI, all the AMPs will search in their own subtable for particular secondary index .For AMPs which found the particular record in their subtable ,it will retrieve the actual data from the AMP and PE will be consolidating the records and give to user
Since NUSI involves all AMP operation , PE will be deciding whether FULL table scan or ALL AMP operation will be more efficient .
| Is This Answer Correct ? | 4 Yes | 0 No |
Post New Answer View All Answers
Explain the term 'row' related to relational database management system?
What are differences between teradata and ansi session modes in teradata?
Highlight a few of the important components of Teradata?
Explain BYNET.
Explain the term 'columns' related to relational database management system?
Highlight a few of the advantages that ETL tools have over Teradata.
Differentiate database data and data warehouse data?
How to run a query in teradata?
If RDBMS is halted what will you do ?
What do high confidence, low confidence and no confidence mean in explain plan?
Steps to create a data model?
if collect stats but it show low confidence why?
Define views in teradata with general syntax.
Explain Teradata performance tuning and optimization?
What can be achieved by using the teradata rdbms?
