Add DBUG "trx" instrumentation that was used for catching MDEV-13470

storage/innobase/row/row0mysql.cc

@@ -740,6 +740,8 @@ row_mysql_handle_errors(
 {
 	dberr_t	err;
 
+	DBUG_ENTER("row_mysql_handle_errors");
+
 handle_new_error:
 	err = trx->error_state;
 
@@ -747,6 +749,9 @@ row_mysql_handle_errors(
 
 	trx->error_state = DB_SUCCESS;
 
+	DBUG_LOG("trx", "handle error: " << ut_strerr(err)
+		 << ";id=" << ib::hex(trx->id) << ", " << trx);
+
 	switch (err) {
 	case DB_LOCK_WAIT_TIMEOUT:
 		if (row_rollback_on_timeout) {
@@ -795,7 +800,7 @@ row_mysql_handle_errors(
 
 		*new_err = err;
 
-		return(true);
+		DBUG_RETURN(true);
 
 	case DB_DEADLOCK:
 	case DB_LOCK_TABLE_FULL:
@@ -840,7 +845,7 @@ row_mysql_handle_errors(
 
 	trx->error_state = DB_SUCCESS;
 
-	return(false);
+	DBUG_RETURN(false);
 }
 
 /********************************************************************//**

storage/innobase/trx/trx0trx.cc

@@ -238,6 +238,7 @@ struct TrxFactory {
 
 		trx_init(trx);
 
+		DBUG_LOG("trx", "Init: " << trx);
 		trx->state = TRX_STATE_NOT_STARTED;
 
 		trx->dict_operation_lock_mode = 0;
@@ -452,6 +453,7 @@ trx_create_low()
 
 	/* Trx state can be TRX_STATE_FORCED_ROLLBACK if
 	the trx was forced to rollback before it's reused.*/
+	DBUG_LOG("trx", "Create: " << trx);
 	trx->state = TRX_STATE_NOT_STARTED;
 
 	heap = mem_heap_create(sizeof(ib_vector_t) + sizeof(void*) * 8);
@@ -630,6 +632,7 @@ trx_free_prepared(
 
 	ut_d(trx->in_rw_trx_list = FALSE);
 
+	DBUG_LOG("trx", "Free prepared: " << trx);
 	trx->state = TRX_STATE_NOT_STARTED;
 
 	/* Undo trx_resurrect_table_locks(). */
@@ -1753,6 +1756,7 @@ trx_commit_in_memory(
 		ut_ad(!(trx->in_innodb
 			& (TRX_FORCE_ROLLBACK | TRX_FORCE_ROLLBACK_ASYNC)));
 
+		DBUG_LOG("trx", "Autocommit in memory: " << trx);
 		trx->state = TRX_STATE_NOT_STARTED;
 
 	} else {
@@ -1888,8 +1892,10 @@ trx_commit_in_memory(
 	if (trx->abort) {
 
 		trx->abort = false;
+		DBUG_LOG("trx", "Abort: " << trx);
 		trx->state = TRX_STATE_FORCED_ROLLBACK;
 	} else {
+		DBUG_LOG("trx", "Commit in memory: " << trx);
 		trx->state = TRX_STATE_NOT_STARTED;
 	}
 
@@ -2061,6 +2067,7 @@ trx_cleanup_at_db_startup(
 	ut_ad(trx->is_recovered);
 	ut_ad(!trx->in_rw_trx_list);
 	ut_ad(!trx->in_mysql_trx_list);
+	DBUG_LOG("trx", "Cleanup at startup: " << trx);
 	trx->state = TRX_STATE_NOT_STARTED;
 }