Query Optimization

Column statistics are now automatically gathered on rowstore tables. This is in addition to column statistics being automatically gathered on columnstore tables, which was done previously.

Range statistics (histograms) are now automatically gathered on columnstore and rowstore tables.

Rowstore table sampling has been improved.

Now, a true row-level random sample of rows from columnstore tables is maintained automatically and used to estimate the selectivity of complex predicates.

All shapes of bushy joins are now supported.

Common Table Expressions (CTEs) can now be materialized; redundant expressions can use cached data instead of being recomputed.