Remove trx_t::has_search_latch and simplify debug code

When the btr_search_latch was split into an array of latches
in MySQL 5.7.8 as part of the Oracle Bug#20985298 fix, the "caching"
of the latch across storage engine API calls was removed, and
the field trx->has_search_latch would only be set during a short
time frame in the execution of row_search_mvcc(), which was
formerly called row_search_for_mysql().

This means that the column
INFORMATION_SCHEMA.INNODB_TRX.TRX_ADAPTIVE_HASH_LATCHED will always
report 0. That column cannot be removed in MariaDB 10.2, but it
can be removed in future releases.

trx_t::has_search_latch: Remove.

trx_assert_no_search_latch(): Remove.

row_sel_try_search_shortcut_for_mysql(): Remove a redundant condition
on trx->has_search_latch (it was always true).

sync_check_iterate(): Make the parameter const.

sync_check_functor_t: Make the operator() const, and remove result()
and the virtual destructor. There is no need to have mutable state
in the functors.

sync_checker<bool>: Replaces dict_sync_check and btrsea_sync_check.

sync_check: Replaces btrsea_sync_check.

dict_sync_check: Instantiated from sync_checker.

sync_allowed_latches: Use std::find() directly on the array.
Remove the std::vector.

TrxInInnoDB::enter(), TrxInInnoDB::exit(): Remove obviously redundant
debug assertions on trx->in_depth, and use equality comparison against 0
because it could be more efficient on some architectures.

1 files changed, 0 insertions, 4 deletions

diff --git a/storage/innobase/trx/trx0i_s.cc b/storage/innobase/trx/trx0i_s.cc
index fcc50b8c76d..7854ad2ab5a 100644
--- a/storage/innobase/trx/trx0i_s.cc
+++ b/storage/innobase/trx/trx0i_s.cc
@@ -589,10 +589,6 @@ thd_done:
 		row->trx_foreign_key_error = NULL;
 	}
 
-#ifdef BTR_CUR_HASH_ADAPT
-	row->trx_has_search_latch = (ibool) trx->has_search_latch;
-#endif /* BTR_CUR_HASH_ADAPT */
-
 	row->trx_is_read_only = trx->read_only;
 
 	row->trx_is_autocommit_non_locking = trx_is_autocommit_non_locking(trx);