Andy Levy shares some thoughts:
I’ve spent a lot of time over the past 8 or years trying to “right the ship.” Systems that have been built and evolved over 10-15 years and the cracks are starting to show. Yes, there’s always the hot spot code that desperately needs attention, the stored procedure that runs in 6 hours but could be 20 minutes with the right adjustments. But I’m looking at a macro level today, more “operational” than “surgical.” When I see __ in a chunk of code, it’s a signal to me that there are overarching problems in how the whole system I’m working on was built and it’s going to take me a good, long while to undo that to deliver constant performance as data grows or improve maintainability.
Andy’s main topic is pre-populated temp tables serving as lookup tables in queries. Though if Andy wants eldrich temp table horrors, I raise him global temp tables (##table) created from a separate session and a SQL Agent job that runs every minute to create it, with people ignoring the failures because “That’s how it’s supposed to work.”
I’ve never seen that in practice, but now I kind of want to do it.
Bonus comment: leading semi-colons for CTEs. I rarely do that, but when I do, it’s because a semi-colon on the same line as a batch separator doesn’t count. In other words,
GO;
WITH records as (...)returns an error. There might be some workable variant, admittedly, but in those cases, I do put the semi-colon in front of the CTE. The rest of the time, when I know there isn’t a batch separator right before the common table expression, I of course don’t. Commas and semi-colons belong at the end, not the beginning.