Sql server lock table while updating sex dating in newcastleton roxburghshire
Transaction two is now waiting on transaction one to complete before it continues execution.Now, transaction one executes: Transaction one attempts to acquire a row-level lock on the specified row, but it cannot: transaction two already holds such a lock. Thus, transaction one is blocked on transaction two, and transaction two is blocked on transaction one: a deadlock condition.(However, a transaction never conflicts with itself.
For example, if transaction 1 acquires an exclusive lock on table A and then tries to acquire an exclusive lock on table B, while transaction 2 has already exclusive-locked table B and now wants an exclusive lock on table A, then neither one can proceed.
In the example above, if both transactions had updated the rows in the same order, no deadlock would have occurred.
One should also ensure that the first lock acquired on an object in a transaction is the most restrictive mode that will be needed for that object.
However, no transaction is allowed to update, delete, or exclusively lock a row on which any other transaction holds a shared lock.
Any attempt to do so will block until the shared lock(s) have been released.