The idea of the patch
is that every cursor gets its own lock id for table level locking.
Thus cursors are protected from updates performed within the same
connection. Additionally a list of transient (must be closed at
commit) cursors is maintained and all transient cursors are closed
when necessary. Lastly, this patch adds support for deadlock
timeouts to TLL locking when using cursors.
+ post-review fixes.
* Renamed handler::estimate_number_of_rows to handler::estimate_rows_upper_bound function, which can also return "unknown"
* made filesort to use full sort buffer if number of rows to sort is not known.
