Multiple aggregations and the SQL table function: A case study
October 9, 2014 Leave a comment
The DB2 Social media team caught up with Nattavut Sutyanyong and Kanishka Mandal who are part of the DB2 development team to talk to them about their article “Multiple aggregations and the SQL table function: A case study“. Here is what they has to say :
1) Why should someone read this article?
This article is useful to DBAs or SQL writers who design large DB2 queries that join several tables to create daily, weekly or monthly reports for their business analysis. These kinds of queries are often used by data warehouse customers.
2) What problem does it solve?
This article helps in an environment where reports are generated with the same tables accessed multiple times. So it mainly focuses on data fetch redundancy and table data encapsulation.
3) What products are discussed in the paper?
Although the article focuses on the DB2 for LUW product, it can also be used in warehousing queries. The idea behind the case study can be applied in any DBMS that supports SQL. The optimization and encapsulation techniques discussed in this paper are performed at the SQL language level: they are not specific to DB2 for LUW.
4) Do have any special tips?
The example shown in the article creates a common table which is used as a parent table and with which other tables can be joined to this table in order to avoid redundancy of data fetched.
About the authors:
Nattavut has been working in SQL rewrite and optimization in DB2 LUW for 14 years. He has been helping numerous IBM customers and partners in tuning their SQL, improving the performance of the systems.
DB2 Development – Query Compiler
Current project: UDX solution in dynamite
IBM Toronto Lab
Kanishka is working as DB2 LUW Worldwide advanced support analyst for 8 years.His current expertise are in High avaliablity in DB2, Purescale, And enhancing and benchmarking several customer environments.
DB2 LUW Advanced support
IBM ISL, Pune