SQL Server performance with many concurrent, long-running queries

Question

I\'m wondering how executing many long-running queries simultaneously will impact SQL Server\'s ability to service each query in a timely fashion.

[Edit]

Answer 1

Hard to say.

• Massive parallel queries?
• Thousands of small ones?
• OLTP or warehouse?
• CPU or IO or Memory bound?
• Server hardware and settings? MAXDOP, RAID etc
• Same set of data? (in buffer pool or lots of churning of in-memory data)

We have 100 million rows tables with sub 1 second aggregate queries running many time during working hours, and 10,000 rows table queries that take 20 seconds but only run once at 4am.