At 07:58 PM 5/14/03 +0400, Nickolay Samofatov wrote:

>3. DPM/VIO code has a lot of places where deadlocks are possible.
>Many places in DPM rely on fixed 1 second timeouts to detect and process
>deadlocks. The problem is that deadlocks are now getting reported before
>1 second timeout and page locking retry loop is looping too quickly.
>If I add manual 1-second timeout in those loops everything will work as
>it worked before.

Interesting. Didn't used to work that way. It was original designed to be
logically deadlock free, meaning 1) any physical deadlock was a serious
logical error that would almost certainly result in corrupted databases,
and b) deadlock recover code was not only not needed but couldn't be
tested.

A bona fide deadlock in the physical access paths means the database
isn't careful write. And if it's not careful write, it's not guaranteed valid
after a system crash.

Jim Starkey