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Blog do Ezequiel
Portuguese PFE SQL Server Team


  • Blog Post: When do conversions generate conversion warnings? And why are these bad?

    Hello, A few days ago a colleague asked me why was he seeing implicit conversions in the execution plan, but no warnings of such sort were being issued. Warnings are seen in the plan if the conditions they affect occur, and then are surfaced in the <Warnings> element of SHOWPLAN, either as affecting...
  • Blog Post: Table variables and row estimations – Part 2

    Hello again, On my previous post , we covered how the Query Optimizer handles row estimation when using Table variables under specific conditions. Following up on that, I will demonstrate other scenarios where the Query Optimizer must try to optimize queries when no statistics and histograms are...
  • Blog Post: Table variables and row estimations – Part 1

    Hello all, The subject of estimated rows vs. actual rows in plan execution has a lot of impact in query performance, and the source of these skews can be quite diverse, from outdated statistics, to incorrect sampling, or the inability of the query processor to know the value of certain variables at...
  • Blog Post: A case of seeks and scans

    Hello all, A couple weeks ago while I was onsite, I was looking at some queries that had performance issues. To the customer, one in particular had become a conundrum that could not be easily answered with the usual approach of good indexing, simply because there was already a good covering index...
  • Blog Post: Auto Update Statistics Asynch - Are you really, really using it?

    Hello all, It’s been awhile since I’ve updated the blog from my part. It’s been a rough month, and I’ve been on vacation prior to that, but I’m back. What I want to get your attention in this post is to the “Auto Update Statistics Asynchronously” database...
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