SQL Server Performance Office Hours Episode 37

SQL Server Performance Office Hours Episode 37

* Does the order of INNER JOINs in a view impact how the queryoptimizer chooses how to build the execution-plan?

* Is there any performance gains when inserting into temp-tables to use the WITH (TABLOCK) hint? Thanks!

* Hey Erik! Is it data or data? I’ve heard some people saying data but I say data like you, so I think I’m right.

* 1. In our high-volume OLTP fintech environment on SQL 2017 EE, we have poor DB design leading to increasing deadlocks and blocking (readers blocking writers). As a short-term fix, we’ve set low deadlock priority on readers and high on critical writers, to avoid even more NOLOCK. We want to enable RCSI but management worries about safety, especially inaccurate results from in-flight version store data that might roll back. Previous DBA enabled snapshot isolation on a few DBs, but devs likely aren’t using it correctly or understand isolation levels. We have ample tempdb space (rarely used, as devs prefer table variables). How can I prove RCSI is safe? Dev env is limited—only some DBs match prod, with slower HDDs/CPU.

* 2. About 80% of our tables (millions to hundreds of millions of rows) have outdated indexes (5+ years old), despite daily dev work. Queries mostly from EF Core; servers reboot weekly (working to stop), losing index stats—but workload is consistent week-to-week. Biggest issue: slow upserts/deletes on tables with 50+ child tables (no cascading). I propose starting with narrow compressed indexes on FK relationships to avoid table scans. Tried sp_indexcleanup, but low uptime limits results beyond compression. Thoughts on this approach and overall indexing strategy?

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Going Further

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