Dennes Torres is a Data Platform MVP and Software Architect living in Malta who loves SQL Server and software development and has more than 20 years of experience.
Dennes can improve Data Platform Architectures and transform data in knowledge.
He moved to Malta after more than 10 years leading devSQL PASS Chapter in Rio de Janeiro and now is a member of the leadership team of MMDPUG PASS Chapter in Malta organizing meetings, events, and webcasts about SQL Server. He is an MCT, MCSE in Data Platforms and BI, with more titles in software development. He can be found speaking in SQL Saturdays around Europe
Outdated statistics are a major cause of bad query plans in SQL Server’s. Even when we have ‘Auto Update Statistics’ on, this doesn’t solve the problem, because the formula for the number of modifications that triggers the ‘Auto Update Statistics’ is 20% + 500. If your table has 3 million rows you will need to … Read more
I’m from the age when sp_help and it’s variants could give to us almost any information about the database objects. Today the server evolved, we have a lot of powerful DMVs to get all the information we would like. The sp_help procs are still there but sometimes they can’t give to us even some basic … Read more
When you're developing database applications, it pays to check for index scans in the SQL Server query plan cache. Once you've identified the queries, what next? Dennes Torres gives some preliminary guidelines on how to find out why these index scans are being chosen for these queries and how to make the queries run faster and more efficiently.… Read more
How often do you check your query plans during development to see if they contain any warnings? If you're missing them, it means that you're not getting all those hints about missing indexes, join predicates or statistics. Is the query optimiser trying to tell you about implicit conversions? Dennes shows how to view the warnings in plan cache for a particular database using SQL… Read more
SQL Server Data Collector, together with Management Data Warehouse, is a fine and useful component for gathering information centrally about how SQL Server instances are being used, and thereby keeping an eye out for problems. It comes into its own when you have figured out how to configure it to run on maybe hundreds of instances using Central Management Server. Dennes describes how to tame the system so that it scales.… Read more
SQL Server keeps the most-used execution plans in cache, so it doesn't need to recompile the same queries every time. How can we benefit from this to find potential performance problems in execution plans? Let's see how to find some opportunities for optimization by using information held in SQL Server's plan cache.… Read more