[loikujhygthj]

>//does exactly what you think

Bring the database to a grinding halt when it tries to service 1000s of request for different rows in the same table at the same time in parallel rather than just access each line in order and sum them?

[Maascamp]

Is all the data you ever operate on stored in the database? Do you never load things into memory?

[dschobel]

plinq only parallelizes in-memory operations and delegates the interaction with the data-store to whatever adapter you're using.

the AsParallel() should make it clear that you're taking an existing data-set (retrieved in whatever manner you like) and signifying you'd like to execute parallel operations on it.