MDEV-14756 - Remove trx_sys_t::rw_trx_list

Removed trx_sys_t::n_prepared_recovered_trx: never used. Removed trx_sys_t::n_prepared_trx: used only at shutdown, we can perfectly get this value from rw_trx_hash.

Author: svoj

storage/innobase/include/trx0sys.h

@@ -561,6 +561,29 @@ class rw_trx_hash_t
  }
 
 
+ struct eliminate_duplicates_arg
+ {
+ trx_ids_t ids;
+ my_hash_walk_action action;
+ void *argument;
+ eliminate_duplicates_arg(size_t size, my_hash_walk_action act, void* arg):
+ action(act), argument(arg) { ids.reserve(size); }
+ };
+
+
+ static my_bool eliminate_duplicates(rw_trx_hash_element_t *element,
+ eliminate_duplicates_arg *arg)
+ {
+ for (trx_ids_t::iterator it= arg->ids.begin(); it != arg->ids.end(); it++)
+ {
+ if (*it == element->id)
+ return 0;
+ }
+ arg->ids.push_back(element->id);
+ return arg->action(element, arg->argument);
+ }
+
+
 public:
  void init()
  {
@@ -765,6 +788,27 @@ class rw_trx_hash_t
  {
  return iterate(current_trx(), action, argument);
  }
+
+
+ /**
+ Iterates the hash and eliminates duplicate elements.
+
+ @sa iterate()
+ */
+
+ int iterate_no_dups(trx_t *caller_trx, my_hash_walk_action action,
+ void *argument)
+ {
+ eliminate_duplicates_arg arg(size() + 32, action, argument);
+ return iterate(caller_trx, reinterpret_cast<my_hash_walk_action>
+ (eliminate_duplicates), &arg);
+ }
+
+
+ int iterate_no_dups(my_hash_walk_action action, void *argument)
+ {
+ return iterate_no_dups(current_trx(), action, argument);
+ }
 };
 
 

storage/innobase/lock/lock0lock.cc

@@ -7601,27 +7601,10 @@ lock_trx_release_locks(
 trx_t*	trx)/*!< in/out: transaction */
 {
 check_trx_state(trx);
+ut_ad(trx_state_eq(trx, TRX_STATE_PREPARED)
+ || trx_state_eq(trx, TRX_STATE_ACTIVE));
 
-if (trx_state_eq(trx, TRX_STATE_PREPARED)) {
-
-mutex_enter(&trx_sys->mutex);
-
-ut_a(trx_sys->n_prepared_trx > 0);
---trx_sys->n_prepared_trx;
-
-if (trx->is_recovered) {
-ut_a(trx_sys->n_prepared_recovered_trx > 0);
-trx_sys->n_prepared_recovered_trx--;
-}
-
-mutex_exit(&trx_sys->mutex);
-} else {
-ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE));
-}
-
-boolrelease_lock;
-
-release_lock = (UT_LIST_GET_LEN(trx->lock.trx_locks) > 0);
+bool release_lock = UT_LIST_GET_LEN(trx->lock.trx_locks) > 0;
 
 /* Don't take lock_sys mutex if trx didn't acquire any lock. */
 if (release_lock) {

storage/innobase/trx/trx0roll.cc

@@ -757,8 +757,6 @@ trx_rollback_resurrected(
  && !srv_undo_sources && srv_fast_shutdown) {
 fake_prepared:
 trx->state = TRX_STATE_PREPARED;
-trx_sys->n_prepared_trx++;
-trx_sys->n_prepared_recovered_trx++;
 *all = false;
 goto func_exit;
 }

storage/innobase/trx/trx0sys.cc

@@ -621,6 +621,23 @@ trx_sys_close(void)
 trx_sys = NULL;
 }
 
+
+static my_bool active_count_callback(rw_trx_hash_element_t *element,
+ uint32_t *count)
+{
+ mutex_enter(&element->mutex);
+ if (trx_t *trx= element->trx)
+ {
+ mutex_enter(&trx->mutex);
+ if (trx_state_eq(trx, TRX_STATE_ACTIVE))
+ ++*count;
+ mutex_exit(&trx->mutex);
+ }
+ mutex_exit(&element->mutex);
+ return 0;
+}
+
+
 /*********************************************************************
 Check if there are any active (non-prepared) transactions.
 This is only used to check if it's safe to shutdown.
@@ -629,18 +646,20 @@ ulint
 trx_sys_any_active_transactions(void)
 /*=================================*/
 {
-ulint	total_trx = trx_sys->rw_trx_hash.size();
+uint32_t total_trx = 0;
+
+trx_sys->rw_trx_hash.iterate_no_dups(
+reinterpret_cast<my_hash_walk_action>
+(active_count_callback), &total_trx);
 
 trx_sys_mutex_enter();
 for (trx_t* trx = UT_LIST_GET_FIRST(trx_sys->mysql_trx_list);
  trx != NULL;
  trx = UT_LIST_GET_NEXT(mysql_trx_list, trx)) {
-total_trx += trx->state != TRX_STATE_NOT_STARTED;
+if (trx->state != TRX_STATE_NOT_STARTED && !trx->id) {
+total_trx++;
+}
 }
-
-ut_a(total_trx >= trx_sys->n_prepared_trx);
-total_trx -= trx_sys->n_prepared_trx;
-
 trx_sys_mutex_exit();
 
 return(total_trx);

storage/innobase/trx/trx0trx.cc

@@ -697,7 +697,6 @@ trx_disconnect_from_mysql(
 ut_ad(trx_state_eq(trx, TRX_STATE_PREPARED));
 
 trx->is_recovered = true;
-trx_sys->n_prepared_recovered_trx++;
  trx->mysql_thd = NULL;
 /* todo/fixme: suggest to do it at innodb prepare */
 trx->will_lock = 0;
@@ -873,8 +872,6 @@ static void trx_resurrect(trx_undo_t *undo, trx_rseg_t *rseg,
  << " was in the XA prepared state.";
 
  state= TRX_STATE_PREPARED;
- trx_sys->n_prepared_trx++;
- trx_sys->n_prepared_recovered_trx++;
  break;
  default:
  if (is_old_insert && srv_force_recovery < SRV_FORCE_NO_TRX_UNDO)
@@ -1003,10 +1000,6 @@ trx_lists_init_at_db_start()
 undo->rseg->space;
 }
 trx_resurrect_table_locks(trx, undo);
-if (trx_state_eq(trx, TRX_STATE_PREPARED)) {
-trx_sys->n_prepared_trx++;
-trx_sys->n_prepared_recovered_trx++;
-}
 }
 }
 }
@@ -2631,7 +2624,6 @@ trx_prepare(
 ut_a(trx->state == TRX_STATE_ACTIVE);
 trx_sys_mutex_enter();
 trx->state = TRX_STATE_PREPARED;
-trx_sys->n_prepared_trx++;
 trx_sys_mutex_exit();
 /*--------------------------------------*/