How does indexing improve query performance?

Answer Posted / praveen

By creating index on single or multiple columns, query
takes index access path instead of full table scan. Full
table scan is costilier operation where it has to visit all
rows in the table whereas index operation just accesses the
index sub table with required hash value and joins with the
basetable using rowid. This improves response time and
performance of the query.

Is This Answer Correct ?    28 Yes 3 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Explain the term 'tables' related to relational database management system?

601


What is the purpose of indexes?

598


How do you verify a complicated sql?

635


Explain the meaning of Amp?

597


List out all forms of LOCKS that are available in Teradata.

558






What are the various indexes in teradata? Why are they preferred?

565


What do you mean by tpt in teradata?

593


What are the multiload utility limitations?

597


How you will check the version of teradata?

590


What is the command in bteq to check for session settings ?

636


Can we collect statistics on table level?

607


What is the use of stored procedures in teradata?

570


What are differences between teradata and ansi session modes in teradata?

632


What do high confidence, low confidence and no confidence mean in explain plan?

594


Explain the teradata primary index mechanics in detail with a diagram.

571