Dynamic task mapping vs many parallel operators

We saw the same issue, fixing the partition filter dropped runtime 60%.

Agree on the staging table swap. Atomic promote prevented partial reads.

We saw the same issue, fixing the partition filter dropped runtime 60%.

Start with the execution plan, numbers beat guesses.

Note that merge on Delta still needs unique keys defined correctly.

Note that merge on Delta still needs unique keys defined correctly.

Prefer a staging table plus validation gate before promoting to prod tables.

Careful with NULL in join keys, they'll drop rows in an inner join.