We're running SQL Server 2008 R2 and the views in question are not indexed.
Originally the SELECTs against the views ran less than a second.
But, after a period of time (about 10 days), the performance on the views degrades to 50-60 seconds.
The server is very active and the underlying tables are updated frequently;
so there is some index fragmentation during the week but we we are doing weekly reorgs,
and that doesn't look like the issue.
However, IF we just recreate the view, performance returns to the sub-second range again
- and remains there... until the next time.
Can someone explain what may be happening?