trx0roll.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

	if (!ins_undo || ins_undo->empty) {
		undo = upd_undo;
	} else if (!upd_undo || upd_undo->empty) {
		undo = ins_undo;
	} else if (ut_dulint_cmp(upd_undo->top_undo_no,
				 ins_undo->top_undo_no) > 0) {
		undo = upd_undo;
	} else {
		undo = ins_undo;
	}

	if (!undo || undo->empty
			|| (ut_dulint_cmp(limit, undo->top_undo_no) > 0)) {

	    	if ((trx->undo_no_arr)->n_used == 0) {
			/* Rollback is ending */
			
			mutex_enter(&(rseg->mutex));

			trx_roll_try_truncate(trx);

			mutex_exit(&(rseg->mutex));
		}

		mutex_exit(&(trx->undo_mutex));

		return(NULL);
	}

	if (undo == ins_undo) {
		is_insert = TRUE;
	} else {
		is_insert = FALSE;
	}
	
	*roll_ptr = trx_undo_build_roll_ptr(is_insert, (undo->rseg)->id,
					undo->top_page_no, undo->top_offset);
	mtr_start(&mtr);

	undo_rec = trx_roll_pop_top_rec(trx, undo, &mtr);

	undo_no = trx_undo_rec_get_undo_no(undo_rec);

	ut_ad(ut_dulint_cmp(ut_dulint_add(undo_no, 1), trx->undo_no) == 0);

	/* We print rollback progress info if we are in a crash recovery
	and the transaction has at least 1000 row operations to undo. */

	if (trx == trx_roll_crash_recv_trx && trx_roll_max_undo_no > 1000) {

	  	progress_pct = 100 - (ulint)
				((ut_conv_dulint_to_longlong(undo_no) * 100)
				/ trx_roll_max_undo_no);
		if (progress_pct != trx_roll_progress_printed_pct) {
			if (trx_roll_progress_printed_pct == 0) {
				fprintf(stderr,
"\nInnoDB: Progress in percents: %lu", (ulong) progress_pct);
			} else {
				fprintf(stderr,
				" %lu", (ulong) progress_pct);
			}
			fflush(stderr);
			trx_roll_progress_printed_pct = progress_pct;
		}
	}

	trx->undo_no = undo_no;

	if (!trx_undo_arr_store_info(trx, undo_no)) {
		/* A query thread is already processing this undo log record */

		mutex_exit(&(trx->undo_mutex));

		mtr_commit(&mtr);
		
		goto try_again;
	}

	undo_rec_copy = trx_undo_rec_copy(undo_rec, heap);
	
	mutex_exit(&(trx->undo_mutex));

	mtr_commit(&mtr);
	
	return(undo_rec_copy);
}

/************************************************************************
Reserves an undo log record for a query thread to undo. This should be
called if the query thread gets the undo log record not using the pop
function above. */

ibool
trx_undo_rec_reserve(
/*=================*/
			/* out: TRUE if succeeded */
	trx_t*	trx,	/* in: transaction */
	dulint	undo_no)/* in: undo number of the record */
{
	ibool	ret;
	
	mutex_enter(&(trx->undo_mutex));

	ret = trx_undo_arr_store_info(trx, undo_no);
	
	mutex_exit(&(trx->undo_mutex));

	return(ret);
}

/***********************************************************************
Releases a reserved undo record. */

void
trx_undo_rec_release(
/*=================*/
	trx_t*	trx,	/* in: transaction */
	dulint	undo_no)/* in: undo number */
{
	trx_undo_arr_t*	arr;
	
	mutex_enter(&(trx->undo_mutex));

	arr = trx->undo_no_arr;

	trx_undo_arr_remove_info(arr, undo_no);

	mutex_exit(&(trx->undo_mutex));
}

/*************************************************************************
Starts a rollback operation. */	

void
trx_rollback(
/*=========*/
	trx_t*		trx,	/* in: transaction */
	trx_sig_t*	sig,	/* in: signal starting the rollback */
	que_thr_t**	next_thr)/* in/out: next query thread to run;
				if the value which is passed in is
				a pointer to a NULL pointer, then the
				calling function can start running
				a new query thread; if the passed value is
				NULL, the parameter is ignored */
{
	que_t*		roll_graph;
	que_thr_t*	thr;
/*	que_thr_t*	thr2; */

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
	ut_ad((trx->undo_no_arr == NULL) || ((trx->undo_no_arr)->n_used == 0));
	
	/* Initialize the rollback field in the transaction */

	if (sig->type == TRX_SIG_TOTAL_ROLLBACK) {

		trx->roll_limit = ut_dulint_zero;

	} else if (sig->type == TRX_SIG_ROLLBACK_TO_SAVEPT) {
		
		trx->roll_limit = (sig->savept).least_undo_no;

	} else if (sig->type == TRX_SIG_ERROR_OCCURRED) {

		trx->roll_limit = trx->last_sql_stat_start.least_undo_no;
	} else {
		ut_error;
	}

	ut_a(ut_dulint_cmp(trx->roll_limit, trx->undo_no) <= 0);

	trx->pages_undone = 0;

	if (trx->undo_no_arr == NULL) {
		trx->undo_no_arr = trx_undo_arr_create();
	}
	
	/* Build a 'query' graph which will perform the undo operations */

	roll_graph = trx_roll_graph_build(trx);

	trx->graph = roll_graph;
	trx->que_state = TRX_QUE_ROLLING_BACK;

	thr = que_fork_start_command(roll_graph);

	ut_ad(thr);

/*	thr2 = que_fork_start_command(roll_graph);

	ut_ad(thr2); */
	
	if (next_thr && (*next_thr == NULL)) {
		*next_thr = thr;
/*		srv_que_task_enqueue_low(thr2); */
	} else {
		srv_que_task_enqueue_low(thr);
/*		srv_que_task_enqueue_low(thr2); */
	}
}

/********************************************************************
Builds an undo 'query' graph for a transaction. The actual rollback is
performed by executing this query graph like a query subprocedure call.
The reply about the completion of the rollback will be sent by this
graph. */

que_t*
trx_roll_graph_build(
/*=================*/
			/* out, own: the query graph */
	trx_t*	trx)	/* in: trx handle */
{
	mem_heap_t*	heap;
	que_fork_t*	fork;
	que_thr_t*	thr;
/*	que_thr_t*	thr2; */

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */

	heap = mem_heap_create(512);
	fork = que_fork_create(NULL, NULL, QUE_FORK_ROLLBACK, heap);
	fork->trx = trx;

	thr = que_thr_create(fork, heap);
/*	thr2 = que_thr_create(fork, heap); */

	thr->child = row_undo_node_create(trx, thr, heap);  
/*	thr2->child = row_undo_node_create(trx, thr2, heap); */

	return(fork);
}

/*************************************************************************
Finishes error processing after the necessary partial rollback has been
done. */
static
void
trx_finish_error_processing(
/*========================*/
	trx_t*	trx)	/* in: transaction */
{
	trx_sig_t*	sig;
	trx_sig_t*	next_sig;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */

	sig = UT_LIST_GET_FIRST(trx->signals);

	while (sig != NULL) {
		next_sig = UT_LIST_GET_NEXT(signals, sig);

		if (sig->type == TRX_SIG_ERROR_OCCURRED) {

			trx_sig_remove(trx, sig);
		}

		sig = next_sig;
	}

	trx->que_state = TRX_QUE_RUNNING;
}

/*************************************************************************
Finishes a partial rollback operation. */
static
void
trx_finish_partial_rollback_off_kernel(
/*===================================*/
	trx_t*		trx,	/* in: transaction */
	que_thr_t**	next_thr)/* in/out: next query thread to run;
				if the value which is passed in is a pointer
				to a NULL pointer, then the calling function
				can start running a new query thread; if this
				parameter is NULL, it is ignored */
{
	trx_sig_t*	sig;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */

	sig = UT_LIST_GET_FIRST(trx->signals);

	/* Remove the signal from the signal queue and send reply message
	to it */

	trx_sig_reply(sig, next_thr);
	trx_sig_remove(trx, sig);

	trx->que_state = TRX_QUE_RUNNING;
}

/********************************************************************
Finishes a transaction rollback. */

void
trx_finish_rollback_off_kernel(
/*===========================*/
	que_t*		graph,	/* in: undo graph which can now be freed */
	trx_t*		trx,	/* in: transaction */
	que_thr_t**	next_thr)/* in/out: next query thread to run;
				if the value which is passed in is
				a pointer to a NULL pointer, then the
   				calling function can start running
				a new query thread; if this parameter is
				NULL, it is ignored */
{
	trx_sig_t*	sig;
	trx_sig_t*	next_sig;
	
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */

	ut_a(trx->undo_no_arr == NULL || trx->undo_no_arr->n_used == 0);

	/* Free the memory reserved by the undo graph */
	que_graph_free(graph);

	sig = UT_LIST_GET_FIRST(trx->signals);

	if (sig->type == TRX_SIG_ROLLBACK_TO_SAVEPT) {

		trx_finish_partial_rollback_off_kernel(trx, next_thr);

		return;

	} else if (sig->type == TRX_SIG_ERROR_OCCURRED) {

		trx_finish_error_processing(trx);

		return;
	}

#ifdef UNIV_DEBUG
	if (lock_print_waits) {			
		fprintf(stderr, "Trx %lu rollback finished\n",
						(ulong) ut_dulint_get_low(trx->id));
	}
#endif /* UNIV_DEBUG */

	trx_commit_off_kernel(trx);

	/* Remove all TRX_SIG_TOTAL_ROLLBACK signals from the signal queue and
	send reply messages to them */

	trx->que_state = TRX_QUE_RUNNING;
	
	while (sig != NULL) {
		next_sig = UT_LIST_GET_NEXT(signals, sig);

		if (sig->type == TRX_SIG_TOTAL_ROLLBACK) {

			trx_sig_reply(sig, next_thr);

			trx_sig_remove(trx, sig);
		}

		sig = next_sig;
	}
}

/*************************************************************************
Creates a rollback command node struct. */

roll_node_t*
roll_node_create(
/*=============*/
				/* out, own: rollback node struct */
	mem_heap_t*	heap)	/* in: mem heap where created */
{
	roll_node_t*	node;

	node = mem_heap_alloc(heap, sizeof(roll_node_t));
	node->common.type = QUE_NODE_ROLLBACK;
	node->state = ROLL_NODE_SEND;

	node->partial = FALSE;
	
	return(node);
}

/***************************************************************
Performs an execution step for a rollback command node in a query graph. */

que_thr_t*
trx_rollback_step(
/*==============*/
				/* out: query thread to run next, or NULL */
	que_thr_t*	thr)	/* in: query thread */
{
	roll_node_t*	node;
	ibool		success;
	ulint		sig_no;
	trx_savept_t*	savept;
	
	node = thr->run_node;

	ut_ad(que_node_get_type(node) == QUE_NODE_ROLLBACK);

	if (thr->prev_node == que_node_get_parent(node)) {
		node->state = ROLL_NODE_SEND;
	}

	if (node->state == ROLL_NODE_SEND) {
		mutex_enter(&kernel_mutex);

		node->state = ROLL_NODE_WAIT;

		if (node->partial) {
			sig_no = TRX_SIG_ROLLBACK_TO_SAVEPT;
			savept = &(node->savept);
		} else {
			sig_no = TRX_SIG_TOTAL_ROLLBACK;
			savept = NULL;
		}

		/* Send a rollback signal to the transaction */

		success = trx_sig_send(thr_get_trx(thr),
					sig_no, TRX_SIG_SELF,
					thr, savept, NULL);

		thr->state = QUE_THR_SIG_REPLY_WAIT;
		
		mutex_exit(&kernel_mutex);

		if (!success) {
			/* Error in delivering the rollback signal */
			que_thr_handle_error(thr, DB_ERROR, NULL, 0);
		}

		return(NULL);
	}

	ut_ad(node->state == ROLL_NODE_WAIT);
		
	thr->run_node = que_node_get_parent(node);
	
	return(thr);
}