jason reeves colbie dating - Sql lock table while updating
Essentially, locks are in-memory structures which have owners, types, and the hash of the resource that it should protect.A lock as an in-memory structure is 96 bytes in size.However, here we need two statements, so we wrap them up in a transaction: Looks fine, right? It has to give an illusion of concurrent operations.
I tried, but failed, to explain that two server processes running the same stored procedure could deadlock.
The problem comes when you need to update some rows in a table, but only when certain other data in each row is set.
There is never any lock escalation to the block level or table level; it is always row-level locking.
Also, Oracle never locks rows except for DML operations (insert, update, delete).
The easy way is to lock the object to prevent contending operations, then release the lock at the end of the atomic operations.