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Fixing Eager Spooling

Erik Darling sends it to the moon:

Probably the most fascinating thing about Eager Index Spools to me is how often the optimizer will insert them into execution plans, often to a query’s detriment.

In a sane world, a non-loop join plan would be chosen, a missing index request would be registered that matches whatever would have been spooled into an index, and we’d all have an easier time.

Read on for a few examples of the problem and two separate ways you can fix it. Remember, kids: friends don’t let friends eagerly spool.