SQL Server Performance Office Hours Episode 38
Questions:
- 3. What are your thoughts on using AI (non-Microsoft) for query optimization and index maintenance? I’ve had 50-70% success tuning queries/indexes with 2-3 LLMs by providing schema/index/stat context first. Considering AI automation: identify poor-performing queries, add env context + tuning rules, use MCP tooling to test in read-only dev env; 3 models propose optimizations, best performer wins and goes to DBA for review. Thinks this is worth pursuing now, since AI will get better over time too? Not worried it will replace my job, performance tuning is only about 5% of my work and changes, generally, only make it to prod if prod reports performance issues. Even when I took the worst offending query and reduced runtime by 12X (no exaggeration) using indexed temp tables and a CTE to do aggregates then join on the temp tables instead of repeated joins on the same tables over and over. The change was *I think* was “too good to be true” and “might have a logic flaw that we can’t properly test for in dev” and thus hasn’t made it to prod… sorry for the rant.
- Lets say there is a table with Key column of number but it has trailing zeros (may be obe or two zero), i had that column as varchar, but business would never put zero when searching for that column. All out queries had like clause with ‘%%’, that killed the perofrmance. How would you approach the problem ?
- I’ve never seen anyone use a plan guide, not even in a blog post or quick video. Any idea why? When do you use them?
- We have a UDF as a default expression for a column on a table. Does SQL Server still evaluate the UDF in default expression even when I explicitly insert values into that column?
- Hey Erik. It took me many months, but I’ve finished watching all of your videos and turned your lessons into a drinking game. What do you think? I’m playing it right now https://dbfiddle.uk/CQbdBNH5
To ask your questions, head over here.
Going Further
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