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February 19, 2019

Tuning Queries Using Database Links
In February's session, Chris looked at options for tuning distributed queries; aka those using database links.

Highlights include:

06:10 - Challenges with getting the execution plan for distributed queries
08:00 - How to get execution details for the queries run on the remote DBs
15:00 - How to minimize network roundtrips to improve DB link queries:
17:10 - The driving_site hint
21:50 - Use the no_merge hint to ensure joins happen remotely
25:00 - Remove the network from the equation by using materialized views
27:30 - Demo of how to diagnose and tune a distributed query
37:25 - Recap of process for diagnosing and tuning database link queries

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Your Experts
Chris Saxon
Chris Saxon, Oracle Developer Advocate for SQL    
Chris Saxon is the quizmaster for the Database Design competitions and an Oracle Developer Advocate for SQL. His job is to help you get the best out of the Oracle Database and have fun with SQL! He's also part of the answer team on Ask TOM and creates YouTube videos at The Magic of SQL channel.
Keith Laker
Keith Laker, Senior Principal Product Manager    
I have been working with Oracle data warehouse technology for over 20 years working on a wide variety of data warehouse projects both as a consultant and an onsite support engineer. I am now part of the Data Warehouse Product Management Team where I am responsible for analytical SQL. I am based in the UK at our Manchester office. A key part of my role is to work with our sales teams to brief our customers on data warehousing and analytical SQL: explaining the wide variety of new and exciting opportunities that our DW and analytical solutions can support. I regularly deliver sales training for data warehousing and analytical SQL across all our sales regions and provide competitive intelligence support across all the major data warehouse vendors.