Continuing his series on optimization thresholds, Itzik Ben-Gan dives into the calculations behind stream aggregate costing when the data needs to be sorted first.
Continuing his series on row goals, Paul White explains how they can impact certain types of semi joins, and how you can spot these effects in showplan and trace flag output.
Paul White provides some great information about row goals, explaining why they're important to understand when examining why the query optimizer made a certain choice.
