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More Notes on Parameter Sensitive Plan Optimization

Erik Darling continues a series on Parameter Sensitive Plan Optimization. First up is a missed opportunity:

If we re-run the procedure from the section up above to search for VoteTypeId 2 a second time, Memory Grant Feedback will fix the spill at the Hash Join, and bring the total execution time down to about 15 seconds.

That is an improvement, but… Look at the plan here. If VoteTypeId 2 uses a plan more suited to the number of rows it has to process, the overall time is around 4 seconds, with no need for a memory grant correction.

Second, Erik asks the pressing questions:

Under more favorable circumstances, dynamic SQL gets run, executed, and plans cached and reused with the same frequency as stored procedures.

Now, dynamic SQL isn’t exactly the same as stored procedures. There’s a lot you can do with those that just looks a mess in dynamic SQL, especially longer bits of code.

In today’s post, we’re going to look at how the Parameter Sensitive Plan (PSP) optimization works with dynamic SQL.

Read on to see if PSP works with dynamic SQL.