13 plans remained the same<\/li>\n<\/ul>\nHow consistent were the results across tests?\u00a0 It was repeatable.\u00a0 I did three test rounds where the skew was identical across workloads for the new CE and and for the old \u2013 as I would expect (and ruling out any rogue background queries jumping in during my test or new query hash values \u2013 there were 28 query_hash values I could keep track of).<\/p>\n
Now again, this is just root-level skew.\u00a0 Quite a bit can be buried in the leaf and intermediate levels of the plan, so I\u2019ll be exploring changes there as well, but I thought this would be an interesting first cut at the overall workload estimate changes.<\/p>\n
More to come\u2026<\/p>\n","protected":false},"excerpt":{"rendered":"
This post is a continuation of the SQL Server 2014 Cardinality Estimator enhancements exploration series: A first look at the query_optimizer_estimate_cardinality XE event \u201cCSelCalcCombineFilters_ExponentialBackoff\u201d Calculator \u201cCSelCalcCombineFilters_ExponentialBackoff\u201d Calculator\u2013 Part II The CSelCalcAscendingKeyFilter Calculator Cardinality Estimation Model Version In the previous post I showed you how to start using the new SQL Server 2014 CE model, but […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42,28],"tags":[],"class_list":["post-1115","post","type-post","status-publish","format-standard","hentry","category-cardinality-estimation","category-performance"],"yoast_head":"\n
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He has worked as a SQL Server professional since 1997 and has supported and developed for SQL Server environments in financial services, IT consulting, manufacturing, retail and the real estate industry. Prior to joining SQLskills he worked at Microsoft as a Premier Field Engineer supporting very large enterprise customer environments. He was responsible for providing deep SQL Server advisory services, training, troubleshooting and ongoing solutions guidance. His areas of expertise include performance tuning, scalability, T-SQL development and high-availability. In 2006 Joe earned the \u201cMicrosoft Certified Master: SQL Server 2005\u201d certification and in 2008 he earned the \u201cMicrosoft Certified Master: SQL Server 2008\u201d certification. In 2009 he took over responsibility for the entire SQL Server Microsoft Certified Master program and held that post until 2011. 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<\/a><\/p>\n