* Implementation of optimistic lock pattern
Try to insert the remote cache key and handle integrity error
* Remove transaction
Integrity error inside a transaction results in deadlock
* Remove check for existing remote cache key
Is no longer needed since integrity constrain violations are handled
* Add check for integrity constrain violation
Do not update the row if the insert statement fails
for other than an integrity constrain violation
* Handle failing inserts because of deadlocks
If the insert statement fails because of a deadlock
try to update the row
* Add utility function for returning SQL error code
Useful for debugging
* Add logging for failing expired cache key deletion
Do not shallow it completely
* Revert "Add utility function for returning SQL error code"
This reverts commit 8e0b82c79633e7d8bc350823cbbab2ac7a58c0a5.
* Better log for failing deletion of expired cache key
* Add some comments
* Remove check for existing cache key
Attempt to insert the key without checking if it's already there
and handle the error situations
* Do not propagate deadlocks created during update
Most probably somebody else is trying to insert/update
the key at the same time so it is safe enough to ignore it
* remotecache: avoid race condition in set
since set called the database twice without transactions another
operation could insert a value before the first operation completed.
which would raise an error on insert since the data have been inserted
by the other request.
closes#17079
