MDEV-23991 dict_table_stats_lock() has unnecessarily long scope

Patch removes dict_index_t::stats_latch. Table/index statistics now
protected with dict_sys->mutex. That way statistics computation can
happen in parallel in several threads and dict_sys->mutex will be locked
only for a short period of time.

This patch is a joint work with Marko Mäkelä

dict_index_t::lock: make mutable which allows to pass const pointer
when only lock is touched in an object

btr_height_get()
btr_get_size(): make index argument const for better type safety

btr_estimate_number_of_different_key_vals(): now returns computed values
instead of setting fields in dict_index_t directly

remove everything related to dict_index_t::stats_latch

dict_stats_index_set_n_diff(): now returns computed values instead
of setting fields in dict_index_t directly

dict_stats_analyze_index():  now returns computed values instead
of setting fields in dict_index_t directly

Reviewed by: Marko Mäkelä

1 files changed, 0 insertions, 1 deletions

diff --git a/storage/innobase/sync/sync0sync.cc b/storage/innobase/sync/sync0sync.cc
index 2e5558a3294..81bce39df33 100644
--- a/storage/innobase/sync/sync0sync.cc
+++ b/storage/innobase/sync/sync0sync.cc
@@ -102,7 +102,6 @@ mysql_pfs_key_t	buf_block_debug_latch_key;
 # endif /* UNIV_DEBUG */
 mysql_pfs_key_t	checkpoint_lock_key;
 mysql_pfs_key_t	dict_operation_lock_key;
-mysql_pfs_key_t	dict_table_stats_key;
 mysql_pfs_key_t	hash_table_locks_key;
 mysql_pfs_key_t	index_tree_rw_lock_key;
 mysql_pfs_key_t	index_online_log_key;