Query Analysis Deep Dive: 13 Causes of a Slow Query - Fabiano Amorim

What if we could analyze a single query with thirteen different performance problems? In this session we’ll explore a query, understand and fix all thirteen of these problems: 1) There is a nonsargable filter 2) An index is missing 3) It is a query optimizer mistake 4) The subquery is unnecessary 5) Query join order is incorrect 6) A filtered statistic is missing 7) Scalar functions are running twice per each row 8) High number of reads on worktable 9) An unknown syntax could be used 10) Memory grant wasn’t enough 11) Distributed query doesn't look good 12) Residual predicates 13) Avoid window spool ondisk By the end of this session you'll have a checklist to review the next time your query is running slowly.

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