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, 1 insertions, 17 deletions

diff --git a/storage/innobase/include/dict0dict.h b/storage/innobase/include/dict0dict.h
index 49e884d064d..7351b5fb682 100644
--- a/storage/innobase/include/dict0dict.h
+++ b/storage/innobase/include/dict0dict.h
@@ -1459,7 +1459,7 @@ UNIV_INLINE
 rw_lock_t*
 dict_index_get_lock(
 /*================*/
-	dict_index_t*	index)	/*!< in: index */
+	const dict_index_t*	index)	/*!< in: index */
 	MY_ATTRIBUTE((nonnull, warn_unused_result));
 /********************************************************************//**
 Returns free space reserved for future updates of records. This is
@@ -1524,22 +1524,6 @@ void
 dict_mutex_exit_for_mysql(void);
 /*===========================*/
 
-/** Lock the appropriate latch to protect a given table's statistics.
-@param[in]	table		table whose stats to lock
-@param[in]	latch_mode	RW_S_LATCH or RW_X_LATCH */
-void
-dict_table_stats_lock(
-	dict_table_t*	table,
-	ulint		latch_mode);
-
-/** Unlock the latch that has been locked by dict_table_stats_lock().
-@param[in]	table		table whose stats to unlock
-@param[in]	latch_mode	RW_S_LATCH or RW_X_LATCH */
-void
-dict_table_stats_unlock(
-	dict_table_t*	table,
-	ulint		latch_mode);
-
 /********************************************************************//**
 Checks if the database name in two table names is the same.
 @return TRUE if same db name */