Add deprecation warning when variable optimizer_search_depth is given
the value 63.
mysql-test/r/greedy_optimizer.result
Updated with warning text.
mysql-test/r/mysqld--help-notwin.result
Updated with warning from mysqld --help --verbose.
mysql-test/r/mysqld--help-win.result
Updated with warning from mysqld --help --verbose.
sql/sys_vars.cc
Added an update check function to the constructor invocation for
the optimizer_search_depth variable. The function emits a
warning message for the value 63.
The greedy optimizer tracks the current level of nested joins and the position
inside these by setting and maintaining a state that's global for the whole FROM
clause.
This state was correctly maintained inside the selection of the next partial plan
table (in best_extension_by_limited_search()).
greedy_search() also moves the current position by adding the last partial match
table when there's not enough tables in the partial plan found by
best_extension_by_limited_search().
This may require update of the global state variables that describe the current
position in the plan if the last table placed by greedy_search is not a top-level
join table.
Fixed by updating the state after placing the partial plan table in greedy_search()
in the same way this is done on entering the best_extension_by_limited_search().
Fixed the signature of the function called to update the state :
check_interleaving_with_nj
- added join cache indication in EXPLAIN (Extra column).
- prefer filesort over full scan over
index for ORDER BY (because it's faster).
- when switching from REF to RANGE because
RANGE uses longer key turn off sort on
the head table only as the resulting
RANGE access is a candidate for join cache
and we don't want to disable it by sorting
on the first table only.
