Exemplo n.º 1
0
/*
* find connection by user and database
*/
POOL_CONNECTION_POOL *pool_get_cp(char *user, char *database, int protoMajor, int check_socket)
{
#ifdef HAVE_SIGPROCMASK
	sigset_t oldmask;
#else
	int	oldmask;
#endif

	int i;

	POOL_CONNECTION_POOL *p = pool_connection_pool;

	if (p == NULL)
	{
		pool_error("pool_get_cp: pool_connection_pool is not initialized");
		return NULL;
	}

	POOL_SETMASK2(&BlockSig, &oldmask);

	for (i=0;i<pool_config.max_pool;i++)
	{
		if (MASTER_CONNECTION(p) &&
			MASTER_CONNECTION(p)->sp->major == protoMajor &&
			MASTER_CONNECTION(p)->sp->user != NULL &&
			strcmp(MASTER_CONNECTION(p)->sp->user, user) == 0 &&
			strcmp(MASTER_CONNECTION(p)->sp->database, database) == 0)
		{
			/* mark this connection is under use */
			MASTER_CONNECTION(p)->closetime = 0;
			POOL_SETMASK(&oldmask);

			if (check_socket &&
				(check_socket_status(MASTER(p)->fd) < 0 ||
				 (DUAL_MODE && check_socket_status(MASTER(p)->fd) < 0)))
			{
				pool_log("connection closed. retry to create new connection pool.");
				pool_free_startup_packet(MASTER_CONNECTION(p)->sp);
				pool_close(MASTER_CONNECTION(p)->con);
				free(MASTER_CONNECTION(p));

				if (DUAL_MODE)
				{
					pool_close(SECONDARY_CONNECTION(p)->con);
					free(SECONDARY_CONNECTION(p));
				}

				memset(p, 0, sizeof(POOL_CONNECTION_POOL));
				return NULL;
			}

			return p;
		}
		p++;
	}

	POOL_SETMASK(&oldmask);
	return NULL;
}
Exemplo n.º 2
0
static POOL_CONNECTION_POOL *connect_backend(StartupPacket *sp, POOL_CONNECTION *frontend)
{
	POOL_CONNECTION_POOL *backend;
	int i;

	/* connect to the backend */
	backend = pool_create_cp();
	if (backend == NULL)
	{
		pool_send_error_message(frontend, sp->major, "XX000", "connection cache is full", "",
								"increase max_pool", __FILE__, __LINE__);
		pool_close(frontend);
		pool_free_startup_packet(sp);
		return NULL;
	}

	for (i=0;i<NUM_BACKENDS;i++)
	{
		if (VALID_BACKEND(i))
		{
			/* set DB node id */
			CONNECTION(backend, i)->db_node_id = i;

			/* mark this is a backend connection */
			CONNECTION(backend, i)->isbackend = 1;
			pool_ssl_negotiate_clientserver(CONNECTION(backend, i));

			/*
			 * save startup packet info
			 */
			CONNECTION_SLOT(backend, i)->sp = sp;

			/* send startup packet */
			if (send_startup_packet(CONNECTION_SLOT(backend, i)) < 0)
			{
				pool_error("do_child: fails to send startup packet to the %d th backend", i);
				pool_discard_cp(sp->user, sp->database, sp->major);
				pool_close(frontend);
				return NULL;
			}
		}
	}

	/*
	 * do authentication stuff
	 */
	if (pool_do_auth(frontend, backend))
	{
		pool_close(frontend);
		pool_discard_cp(sp->user, sp->database, sp->major);
		return NULL;
	}

	return backend;
}
Exemplo n.º 3
0
/*
 * Do house keeping works when pgpool child process exits
 */
void child_exit(int code)
{
	if (getpid() == mypid)
	{
		pool_log("child_exit: called from pgpool main. ignored.");
		return;
	}

	/* count down global connection counter */
	if (accepted)
		connection_count_down();

	/* prepare to shutdown connections to system db */
	if(pool_config->parallel_mode || pool_config->enable_query_cache)
	{
		if (system_db_info->pgconn)
			pool_close_libpq_connection();
		if (pool_system_db_connection())
			pool_close(pool_system_db_connection()->con);
	}

	if (pool_config->memory_cache_enabled && !pool_is_shmem_cache())
	{
		memcached_disconnect();
	}

	/* let backend know now we are exiting */
	if (pool_connection_pool)
		send_frontend_exits();

	exit(code);
}
Exemplo n.º 4
0
/*
 * Discard connection and memory allocated by
 * make_persistent_db_connection().
 */
void discard_persistent_db_connection(POOL_CONNECTION_POOL_SLOT *cp)
{
	int len;

	if(cp == NULL)
		return;

	pool_write(cp->con, "X", 1);
	len = htonl(4);
	pool_write(cp->con, &len, sizeof(len));

	/*
	 * XXX we cannot call pool_flush() here since backend may already
	 * close the socket and pool_flush() automatically invokes fail
	 * over handler. This could happen in copy command (remember the
	 * famous "lost synchronization with server, resetting
	 * connection" message)
	 */
	pool_set_nonblock(cp->con->fd);
	pool_flush_it(cp->con);
	pool_unset_nonblock(cp->con->fd);

	pool_close(cp->con);
	free(cp->sp->startup_packet);
	free(cp->sp->database);
	free(cp->sp->user);
	free(cp->sp);
	free(cp);
}
Exemplo n.º 5
0
/*
 * strhash_close: close hash array.
 *
 *	i)	sh	STRHASH structure
 */
void
strhash_close(STRHASH *sh)
{
	pool_close(sh->pool);
	free(sh->htab);
	free(sh);
}
Exemplo n.º 6
0
/*
 * disconnect and release a connection to the database
 */
void pool_discard_cp(char *user, char *database, int protoMajor)
{
	POOL_CONNECTION_POOL *p = pool_get_cp(user, database, protoMajor, 0);
	ConnectionInfo *info;
	int i, freed = 0;

	if (p == NULL)
	{
		pool_error("pool_discard_cp: cannot get connection pool for user %s datbase %s", user, database);
		return;
	}

	for (i=0;i<NUM_BACKENDS;i++)
	{
		if (!VALID_BACKEND(i))
			continue;

		if (!freed)
		{
			pool_free_startup_packet(CONNECTION_SLOT(p, i)->sp);
			freed = 1;
		}
		pool_close(CONNECTION(p, i));
		free(CONNECTION_SLOT(p, i));
	}

	info = p->info;
	memset(p, 0, sizeof(POOL_CONNECTION_POOL));
	p->info = info;
	memset(p->info, 0, sizeof(ConnectionInfo) * MAX_NUM_BACKENDS);
}
Exemplo n.º 7
0
/**
 * gfind_close: close iterator.
 */
void
gfind_close(GFIND *gfind)
{
	dbop_close(gfind->dbop);
	if (gfind->flags & GPATH_NEARSORT) {
		pool_close(gfind->pool);
		varray_close(gfind->path_array);
	}
	free((void *)gfind->prefix);
	free(gfind);
}
Exemplo n.º 8
0
/**
 * Command redis
 */
static redisReply* redisCli(server_rec *s, const char *format, ...) {
	redisContext* ctx = pool_open(s);
	void *reply = NULL;
	if (ctx) {
		va_list ap;
		va_start(ap,format);
		reply = redisvCommand(ctx,format,ap);
		va_end(ap);
		pool_close(s, ctx);
	}
	return reply;
}
Exemplo n.º 9
0
/*
 * disconnect and release a connection to the database
 */
void pool_discard_cp(char *user, char *database, int protoMajor)
{
	POOL_CONNECTION_POOL *p = pool_get_cp(user, database, protoMajor, 0);

	if (p == NULL)
	{
		pool_error("pool_discard_cp: cannot get connection pool for user %s datbase %s", user, database);
		return;
	}

	pool_free_startup_packet(MASTER_CONNECTION(p)->sp);
	pool_close(MASTER_CONNECTION(p)->con);
	free(MASTER_CONNECTION(p));

	if (DUAL_MODE)
	{
		/* do not free memory! we did not allocate them */
		pool_close(SECONDARY_CONNECTION(p)->con);
		free(SECONDARY_CONNECTION(p));
	}

	memset(p, 0, sizeof(POOL_CONNECTION_POOL));
}
Exemplo n.º 10
0
/*
 * signal handler for SIGUSR1
 * close all idle connections
 */
static RETSIGTYPE close_idle_connection(int sig)
{
	int i, j;
	POOL_CONNECTION_POOL *p = pool_connection_pool;
	ConnectionInfo *info;

	pool_debug("child receives close connection request");

	for (j=0;j<pool_config->max_pool;j++, p++)
	{
		if (!MASTER_CONNECTION(p))
			continue;
 		if (!MASTER_CONNECTION(p)->sp)
			continue;
		if (MASTER_CONNECTION(p)->sp->user == NULL)
			continue;

		if (MASTER_CONNECTION(p)->closetime > 0)		/* idle connection? */
		{
			pool_debug("close_idle_connection: close idle connection: user %s database %s", MASTER_CONNECTION(p)->sp->user, MASTER_CONNECTION(p)->sp->database);
			pool_send_frontend_exits(p);

			for (i=0;i<NUM_BACKENDS;i++)
			{
				if (!VALID_BACKEND(i))
					continue;

				if (i == 0)
				{
					/* only first backend allocated the memory for the start up packet */
					pool_free_startup_packet(CONNECTION_SLOT(p, i)->sp);
				}
				pool_close(CONNECTION(p, i));
			}
			info = p->info;
			memset(p, 0, sizeof(POOL_CONNECTION_POOL));
			p->info = info;
			memset(p->info, 0, sizeof(ConnectionInfo));
		}
	}
}
Exemplo n.º 11
0
/**
 * gtags_close: close tag file
 *
 *	@param[in]	gtop	#GTOP structure
 */
void
gtags_close(GTOP *gtop)
{
	if (gtop->format & GTAGS_COMPRESS)
		abbrev_close();
	if (gtop->segment_pool)
		pool_close(gtop->segment_pool);
	if (gtop->path_array)
		free(gtop->path_array);
	if (gtop->sb)
		strbuf_close(gtop->sb);
	if (gtop->vb)
		varray_close(gtop->vb);
	if (gtop->path_hash)
		strhash_close(gtop->path_hash);
	gpath_close();
	dbop_close(gtop->dbop);
	if (gtop->gtags)
		dbop_close(gtop->gtags);
	free(gtop);
}
Exemplo n.º 12
0
/*
 * create a persistent connection
 */
POOL_CONNECTION_POOL_SLOT *make_persistent_db_connection(
	char *hostname, int port, char *dbname, char *user, char *password, bool retry)
{
	POOL_CONNECTION_POOL_SLOT *cp;
	int fd;

#define MAX_USER_AND_DATABASE	1024

	/* V3 startup packet */
	typedef struct {
		int protoVersion;
		char data[MAX_USER_AND_DATABASE];
	} StartupPacket_v3;

	static StartupPacket_v3 *startup_packet;
	int len, len1;
	int status;

	cp = malloc(sizeof(POOL_CONNECTION_POOL_SLOT));
	if (cp == NULL)
	{
		pool_error("make_persistent_db_connection: could not allocate memory");
		return NULL;
	}
	memset(cp, 0, sizeof(POOL_CONNECTION_POOL_SLOT));

	startup_packet = malloc(sizeof(*startup_packet));
	if (startup_packet == NULL)
	{
		pool_error("make_persistent_db_connection: could not allocate memory");
		free_persisten_db_connection_memory(cp);
		return NULL;
	}
	memset(startup_packet, 0, sizeof(*startup_packet));
	startup_packet->protoVersion = htonl(0x00030000);	/* set V3 proto major/minor */

	/*
	 * create socket
	 */
	if (*hostname == '/')
	{
		fd = connect_unix_domain_socket_by_port(port, hostname, retry);
	}
	else
	{
		fd = connect_inet_domain_socket_by_port(hostname, port, retry);
	}

	if (fd < 0)
	{
		pool_error("make_persistent_db_connection: connection to %s(%d) failed", hostname, port);
		free_persisten_db_connection_memory(cp);
		free(startup_packet);
		return NULL;
	}

	cp->con = pool_open(fd);
	cp->closetime = 0;
	cp->con->isbackend = 1;
	pool_ssl_negotiate_clientserver(cp->con);

	/*
	 * build V3 startup packet
	 */
	len = snprintf(startup_packet->data, sizeof(startup_packet->data), "user") + 1;
	len1 = snprintf(&startup_packet->data[len], sizeof(startup_packet->data)-len, "%s", user) + 1;
	if (len1 >= (sizeof(startup_packet->data)-len))
	{
		pool_error("make_persistent_db_connection: too long user name");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		free(startup_packet);
		return NULL;
	}

	len += len1;
	len1 = snprintf(&startup_packet->data[len], sizeof(startup_packet->data)-len, "database") + 1;
	if (len1 >= (sizeof(startup_packet->data)-len))
	{
		pool_error("make_persistent_db_connection: too long user name");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		free(startup_packet);
		return NULL;
	}

	len += len1;
	len1 = snprintf(&startup_packet->data[len], sizeof(startup_packet->data)-len, "%s", dbname) + 1;
	if (len1 >= (sizeof(startup_packet->data)-len))
	{
		pool_error("make_persistent_db_connection: too long database name");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		free(startup_packet);
		return NULL;
	}
	len += len1;
	startup_packet->data[len++] = '\0';

	cp->sp = malloc(sizeof(StartupPacket));
	if (cp->sp == NULL)
	{
		pool_error("make_persistent_db_connection: could not allocate memory");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		free(startup_packet);
		return NULL;
	}

	cp->sp->startup_packet = (char *)startup_packet;
	cp->sp->len = len + 4;
	cp->sp->major = 3;
	cp->sp->minor = 0;
	cp->sp->database = strdup(dbname);
	if (cp->sp->database == NULL)
	{
		pool_error("make_persistent_db_connection: could not allocate memory");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		return NULL;
	}
	cp->sp->user = strdup(user);
	if (cp->sp->user == NULL)
	{
		pool_error("make_persistent_db_connection: could not allocate memory");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		return NULL;
	}

	/*
	 * send startup packet
	 */
	status = send_startup_packet(cp);
	if (status)
	{
		pool_error("make_persistent_db_connection: send_startup_packet failed");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		return NULL;
	}

	/*
	 * do authentication
	 */
	if (s_do_auth(cp, password))
	{
		pool_error("make_persistent_db_connection: s_do_auth failed");
		pool_close(cp->con);
		free_persisten_db_connection_memory(cp);
		return NULL;
	}

	return cp;
}
Exemplo n.º 13
0
/*
* find connection by user and database
*/
POOL_CONNECTION_POOL *pool_get_cp(char *user, char *database, int protoMajor, int check_socket)
{
#ifdef HAVE_SIGPROCMASK
	sigset_t oldmask;
#else
	int	oldmask;
#endif

	int i, freed = 0;
	ConnectionInfo *info;

	POOL_CONNECTION_POOL *p = pool_connection_pool;

	if (p == NULL)
	{
		pool_error("pool_get_cp: pool_connection_pool is not initialized");
		return NULL;
	}

	POOL_SETMASK2(&BlockSig, &oldmask);

	for (i=0;i<pool_config->max_pool;i++)
	{
		if (MASTER_CONNECTION(p) &&
			MASTER_CONNECTION(p)->sp &&
			MASTER_CONNECTION(p)->sp->major == protoMajor &&
			MASTER_CONNECTION(p)->sp->user != NULL &&
			strcmp(MASTER_CONNECTION(p)->sp->user, user) == 0 &&
			strcmp(MASTER_CONNECTION(p)->sp->database, database) == 0)
		{
			int sock_broken = 0;
			int j;

			/* mark this connection is under use */
			MASTER_CONNECTION(p)->closetime = 0;
			for (j=0;j<NUM_BACKENDS;j++)
			{
				p->info[j].counter++;
			}
			POOL_SETMASK(&oldmask);

			if (check_socket)
			{
				for (j=0;j<NUM_BACKENDS;j++)
				{
					if (!VALID_BACKEND(j))
						continue;

					if  (CONNECTION_SLOT(p, j))
					{
						sock_broken = check_socket_status(CONNECTION(p, j)->fd);
						if (sock_broken < 0)
							break;
					}
					else
					{
						sock_broken = -1;
						break;
					}
				}

				if (sock_broken < 0)
				{
					pool_log("connection closed. retry to create new connection pool.");
					for (j=0;j<NUM_BACKENDS;j++)
					{
						if (!VALID_BACKEND(j) || (CONNECTION_SLOT(p, j) == NULL))
							continue;

						if (!freed)
						{
							pool_free_startup_packet(CONNECTION_SLOT(p, j)->sp);
							freed = 1;
						}

						pool_close(CONNECTION(p, j));
						free(CONNECTION_SLOT(p, j));
					}
					info = p->info;
					memset(p, 0, sizeof(POOL_CONNECTION_POOL_SLOT));
					p->info = info;
					memset(p->info, 0, sizeof(ConnectionInfo) * MAX_NUM_BACKENDS);
					POOL_SETMASK(&oldmask);
					return NULL;
				}
			}
			POOL_SETMASK(&oldmask);
			pool_index = i;
			return p;
		}
		p++;
	}

	POOL_SETMASK(&oldmask);
	return NULL;
}
Exemplo n.º 14
0
void pool_backend_timer(void)
{
#define TMINTMAX 0x7fffffff

	POOL_CONNECTION_POOL *p = pool_connection_pool;
	int i, j;
	time_t now;
	time_t nearest = TMINTMAX;
	ConnectionInfo *info;

	POOL_SETMASK(&BlockSig);

	now = time(NULL);

	pool_debug("pool_backend_timer_handler called at %ld", now);

	for (i=0;i<pool_config->max_pool;i++, p++)
	{
		if (!MASTER_CONNECTION(p))
			continue;
		if (!MASTER_CONNECTION(p)->sp)
			continue;
		if (MASTER_CONNECTION(p)->sp->user == NULL)
			continue;

		/* timer expire? */
		if (MASTER_CONNECTION(p)->closetime)
		{
			int freed = 0;

			pool_debug("pool_backend_timer_handler: expire time: %ld",
					   MASTER_CONNECTION(p)->closetime+pool_config->connection_life_time);

			if (now >= (MASTER_CONNECTION(p)->closetime+pool_config->connection_life_time))
			{
				/* discard expired connection */
				pool_debug("pool_backend_timer_handler: expires user %s database %s",
						   MASTER_CONNECTION(p)->sp->user, MASTER_CONNECTION(p)->sp->database);

				pool_send_frontend_exits(p);

				for (j=0;j<NUM_BACKENDS;j++)
				{
					if (!VALID_BACKEND(j))
						continue;

					if (!freed)
					{
						pool_free_startup_packet(CONNECTION_SLOT(p, j)->sp);
						freed = 1;
					}

					pool_close(CONNECTION(p, j));
					free(CONNECTION_SLOT(p, j));
				}
				info = p->info;
				memset(p, 0, sizeof(POOL_CONNECTION_POOL));
				p->info = info;
				memset(p->info, 0, sizeof(ConnectionInfo) * MAX_NUM_BACKENDS);

				/* prepare to shutdown connections to system db */
				if(pool_config->system_db_dynamic_connection && (pool_config->parallel_mode || pool_config->enable_query_cache))
				{
					if (system_db_info->pgconn)
						pool_close_libpq_connection();
					if (pool_system_db_connection() && pool_system_db_connection()->con)
					{
						pool_send_frontend_exit(pool_system_db_connection()->con);
						pool_close(pool_system_db_connection()->con);
					}

					if( system_db_info->connection )
					{
						free( system_db_info->connection );
						memset(system_db_info->connection, 0, sizeof(POOL_CONNECTION_POOL_SLOT));
						system_db_info->connection = NULL;
					}
				}
			}
			else
			{
				/* look for nearest timer */
				if (MASTER_CONNECTION(p)->closetime < nearest)
					nearest = MASTER_CONNECTION(p)->closetime;
			}
		}
	}

	/* any remaining timer */
	if (nearest != TMINTMAX)
	{
		nearest = pool_config->connection_life_time - (now - nearest);
		if (nearest <= 0)
		  nearest = 1;
		pool_signal(SIGALRM, pool_backend_timer_handler);
		alarm(nearest);
	}

	POOL_SETMASK(&UnBlockSig);
}
Exemplo n.º 15
0
/*
* create a connection pool by user and database
*/
POOL_CONNECTION_POOL *pool_create_cp(void)
{
	int i, freed = 0;
	time_t closetime;
	POOL_CONNECTION_POOL *oldestp;
	POOL_CONNECTION_POOL *ret;
	ConnectionInfo *info;

	POOL_CONNECTION_POOL *p = pool_connection_pool;

	if (p == NULL)
	{
		pool_error("pool_create_cp: pool_connection_pool is not initialized");
		return NULL;
	}

	for (i=0;i<pool_config->max_pool;i++)
	{
		if (MASTER_CONNECTION(p) == NULL)
		{
			ret = new_connection(p);
			if (ret)
				pool_index = i;
			return ret;
		}
		p++;
	}

	pool_debug("no empty connection slot was found");

	/*
	 * no empty connection slot was found. look for the oldest connection and discard it.
	 */
	oldestp = p = pool_connection_pool;
	closetime = MASTER_CONNECTION(p)->closetime;
	pool_index = 0;

	for (i=0;i<pool_config->max_pool;i++)
	{
		pool_debug("user: %s database: %s closetime: %ld",
				   MASTER_CONNECTION(p)->sp->user,
				   MASTER_CONNECTION(p)->sp->database,
				   MASTER_CONNECTION(p)->closetime);
		if (MASTER_CONNECTION(p)->closetime < closetime)
		{
			closetime = MASTER_CONNECTION(p)->closetime;
			oldestp = p;
			pool_index = i;
		}
		p++;
	}

	p = oldestp;
	pool_send_frontend_exits(p);

	pool_debug("discarding old %zd th connection. user: %s database: %s",
			   oldestp - pool_connection_pool,
			   MASTER_CONNECTION(p)->sp->user,
			   MASTER_CONNECTION(p)->sp->database);

	for (i=0;i<NUM_BACKENDS;i++)
	{
		if (!VALID_BACKEND(i))
			continue;

		if (!freed)
		{
			pool_free_startup_packet(CONNECTION_SLOT(p, i)->sp);
			freed = 1;
		}

		pool_close(CONNECTION(p, i));
		free(CONNECTION_SLOT(p, i));
	}

	info = p->info;
	memset(p, 0, sizeof(POOL_CONNECTION_POOL));
	p->info = info;
	memset(p->info, 0, sizeof(ConnectionInfo) * MAX_NUM_BACKENDS);

	ret = new_connection(p);
	return ret;
}
Exemplo n.º 16
0
/*
* create a connection pool by user and database
*/
POOL_CONNECTION_POOL *pool_create_cp(void)
{
	int i;
	time_t closetime;
	POOL_CONNECTION_POOL *oldestp;

	POOL_CONNECTION_POOL *p = pool_connection_pool;

	if (p == NULL)
	{
		pool_error("pool_create_cp: pool_connection_pool is not initialized");
		return NULL;
	}

	for (i=0;i<pool_config.max_pool;i++)
	{
		if (MASTER_CONNECTION(p) == NULL)
			return new_connection(p);
		p++;
	}

	pool_debug("no empty connection slot was found");

	/*
	 * no empty connection slot was found. look for the oldest connection and discard it.
	 */
	oldestp = p = pool_connection_pool;
	closetime = MASTER_CONNECTION(p)->closetime;
	for (i=0;i<pool_config.max_pool;i++)
	{
		pool_debug("user: %s database: %s closetime: %d",
				   MASTER_CONNECTION(p)->sp->user,
				   MASTER_CONNECTION(p)->sp->database,
				   MASTER_CONNECTION(p)->closetime);
		if (MASTER_CONNECTION(p)->closetime < closetime)
		{
			closetime = MASTER_CONNECTION(p)->closetime;
			oldestp = p;
		}
		p++;
	}

	p = oldestp;
	pool_send_frontend_exits(p);

	pool_debug("discarding old %d th connection. user: %s database: %s", 
			   oldestp - pool_connection_pool,
			   MASTER_CONNECTION(p)->sp->user,
			   MASTER_CONNECTION(p)->sp->database);

	pool_free_startup_packet(MASTER_CONNECTION(p)->sp);
	pool_close(MASTER_CONNECTION(p)->con);
	free(MASTER_CONNECTION(p));

	if (DUAL_MODE)
	{
		/* do not free memory! we did not allocate them */
		pool_close(SECONDARY_CONNECTION(p)->con);
		free(SECONDARY_CONNECTION(p));
	}

	memset(p, 0, sizeof(POOL_CONNECTION_POOL));

	return new_connection(p);
}
Exemplo n.º 17
0
void pool_backend_timer(void)
{
#define TMINTMAX 0x7fffffff

	POOL_CONNECTION_POOL *p = pool_connection_pool;
	int i;
	time_t now;
	time_t nearest = TMINTMAX;

	POOL_SETMASK(&BlockSig);

	now = time(NULL);

	pool_debug("pool_backend_timer_handler called at %d", now);

	for (i=0;i<pool_config.max_pool;i++, p++)
	{
		if (!MASTER_CONNECTION(p))
			continue;
		if (MASTER_CONNECTION(p)->sp->user == NULL)
			continue;

		/* timer expire? */
		if (MASTER_CONNECTION(p)->closetime)
		{
			pool_debug("pool_backend_timer_handler: expire time: %d",
					   MASTER_CONNECTION(p)->closetime+pool_config.connection_life_time);

			if (now >= (MASTER_CONNECTION(p)->closetime+pool_config.connection_life_time))
			{
				/* discard expired connection */
				pool_debug("pool_backend_timer_handler: expires user %s database %s", MASTER_CONNECTION(p)->sp->user, MASTER_CONNECTION(p)->sp->database);

				pool_send_frontend_exits(p);

				pool_free_startup_packet(MASTER_CONNECTION(p)->sp);
				pool_close(MASTER_CONNECTION(p)->con);
				free(MASTER_CONNECTION(p));

				if (DUAL_MODE)
				{
					pool_close(SECONDARY_CONNECTION(p)->con);
					free(SECONDARY_CONNECTION(p));
				}

				memset(p, 0, sizeof(POOL_CONNECTION_POOL));
			}
			else
			{
				/* look for nearest timer */
				if (MASTER_CONNECTION(p)->closetime < nearest)
					nearest = MASTER_CONNECTION(p)->closetime;
			}
		}
	}

	/* any remaining timer */
	if (nearest != TMINTMAX)
	{
		nearest = pool_config.connection_life_time - (now - nearest);
		if (nearest <= 0)
		  nearest = 1;
		pool_signal(SIGALRM, pool_backend_timer_handler);
		alarm(nearest);
	}

	POOL_SETMASK(&UnBlockSig);
}
Exemplo n.º 18
0
/*
* child main loop
*/
void do_child(int unix_fd, int inet_fd)
{
	POOL_CONNECTION *frontend;
	POOL_CONNECTION_POOL *backend;
	struct timeval now;
	struct timezone tz;
	struct timeval timeout;
	static int connected;		/* non 0 if has been accepted connections from frontend */
	int connections_count = 0;	/* used if child_max_connections > 0 */
	int found;
	char psbuf[NI_MAXHOST + 128];

	pool_debug("I am %d", getpid());

	/* Identify myself via ps */
	init_ps_display("", "", "", "");

	/* set up signal handlers */
	signal(SIGALRM, SIG_DFL);
	signal(SIGTERM, die);
	signal(SIGINT, die);
	signal(SIGHUP, reload_config_handler);
	signal(SIGQUIT, die);
	signal(SIGCHLD, SIG_DFL);
	signal(SIGUSR1, close_idle_connection);
	signal(SIGUSR2, wakeup_handler);
	signal(SIGPIPE, SIG_IGN);

#ifdef NONE_BLOCK
	/* set listen fds to none-blocking */
	pool_set_nonblock(unix_fd);
	if (inet_fd)
	{
		pool_set_nonblock(inet_fd);
	}
#endif

	/* Initialize my backend status */
	pool_initialize_private_backend_status();

	/* Initialize per process context */
	pool_init_process_context();

	/* initialize random seed */
	gettimeofday(&now, &tz);
#if defined(sun) || defined(__sun)
	srand((unsigned int) now.tv_usec);
#else
	srandom((unsigned int) now.tv_usec);
#endif

	/* initialize system db connection */
	init_system_db_connection();

	/* initialize connection pool */
	if (pool_init_cp())
	{
		child_exit(1);
	}

	/*
	 * Open pool_passwd in child process.  This is necessary to avoid the
	 * file descriptor race condition reported in [pgpool-general: 1141].
	 */
	if (strcmp("", pool_config->pool_passwd))
	{
		pool_reopen_passwd_file();
	}

	timeout.tv_sec = pool_config->child_life_time;
	timeout.tv_usec = 0;

	for (;;)
	{
		StartupPacket *sp;

		idle = 1;

		/* pgpool stop request already sent? */
		check_stop_request();

		/* Check if restart request is set because of failback event
		 * happend.  If so, exit myself with exit code 1 to be
		 * restarted by pgpool parent.
		 */
		if (pool_get_my_process_info()->need_to_restart)
		{
			pool_log("do_child: failback event found. restart myself.");
			pool_get_my_process_info()->need_to_restart = 0;
			child_exit(1);
		}

		accepted = 0;

		/* perform accept() */
		frontend = do_accept(unix_fd, inet_fd, &timeout);

		if (frontend == NULL)	/* connection request from frontend timed out */
		{
			/* check select() timeout */
			if (connected && pool_config->child_life_time > 0 &&
				timeout.tv_sec == 0 && timeout.tv_usec == 0)
			{
				pool_debug("child life %d seconds expired", pool_config->child_life_time);
				/*
				 * Doesn't need to call this. child_exit() calls it.
				 * send_frontend_exits();
				 */
				child_exit(2);
			}
			continue;
		}

		/* set frontend fd to blocking */
		pool_unset_nonblock(frontend->fd);

		/* reset busy flag */
		idle = 0;

		/* check backend timer is expired */
		if (backend_timer_expired)
		{
			pool_backend_timer();
			backend_timer_expired = 0;
		}

		/* read the startup packet */
	retry_startup:
		sp = read_startup_packet(frontend);
		if (sp == NULL)
		{
			/* failed to read the startup packet. return to the accept() loop */
			pool_close(frontend);
			connection_count_down();
			continue;
		}

		/* cancel request? */
		if (sp->major == 1234 && sp->minor == 5678)
		{
			cancel_request((CancelPacket *)sp->startup_packet);

			pool_close(frontend);
			pool_free_startup_packet(sp);
			connection_count_down();
			continue;
		}

		/* SSL? */
		if (sp->major == 1234 && sp->minor == 5679 && !frontend->ssl_active)
		{
			pool_debug("SSLRequest from client");
			pool_ssl_negotiate_serverclient(frontend);
			goto retry_startup;
		}

		if (pool_config->enable_pool_hba)
		{
			/*
			 * do client authentication.
			 * Note that ClientAuthentication does not return if frontend
			 * was rejected; it simply terminates this process.
			 */
			frontend->protoVersion = sp->major;
			frontend->database = strdup(sp->database);
			if (frontend->database == NULL)
			{
				pool_error("do_child: strdup failed: %s\n", strerror(errno));
				child_exit(1);
			}
			frontend->username = strdup(sp->user);
			if (frontend->username == NULL)
			{
				pool_error("do_child: strdup failed: %s\n", strerror(errno));
				child_exit(1);
			}
			ClientAuthentication(frontend);
		}

		/*
		 * Ok, negotiation with frontend has been done. Let's go to the
		 * next step.  Connect to backend if there's no existing
		 * connection which can be reused by this frontend.
		 * Authentication is also done in this step.
		 */

		/* Check if restart request is set because of failback event
		 * happend.  If so, close idle connections to backend and make
		 * a new copy of backend status.
		 */
		if (pool_get_my_process_info()->need_to_restart)
		{
			pool_log("do_child: failback event found. discard existing connections");
			pool_get_my_process_info()->need_to_restart = 0;
			close_idle_connection(0);
			pool_initialize_private_backend_status();
		}

		/*
		 * if there's no connection associated with user and database,
		 * we need to connect to the backend and send the startup packet.
		 */

		/* look for existing connection */
		found = 0;
		backend = pool_get_cp(sp->user, sp->database, sp->major, 1);

		if (backend != NULL)
		{
			found = 1;

			/* existing connection associated with same user/database/major found.
			 * however we should make sure that the startup packet contents are identical.
			 * OPTION data and others might be different.
			 */
			if (sp->len != MASTER_CONNECTION(backend)->sp->len)
			{
				pool_debug("do_child: connection exists but startup packet length is not identical");
				found = 0;
			}
			else if(memcmp(sp->startup_packet, MASTER_CONNECTION(backend)->sp->startup_packet, sp->len) != 0)
			{
				pool_debug("do_child: connection exists but startup packet contents is not identical");
				found = 0;
			}

			if (found == 0)
			{
				/* we need to discard existing connection since startup packet is different */
				pool_discard_cp(sp->user, sp->database, sp->major);
				backend = NULL;
			}
		}

		if (backend == NULL)
		{
			/* create a new connection to backend */
			if ((backend = connect_backend(sp, frontend)) == NULL)
			{
				connection_count_down();
				continue;
			}
		}

		else
		{
			/* reuse existing connection */
			if (!connect_using_existing_connection(frontend, backend, sp))
				continue;
		}

		connected = 1;

 		/* show ps status */
		sp = MASTER_CONNECTION(backend)->sp;
		snprintf(psbuf, sizeof(psbuf), "%s %s %s idle",
				 sp->user, sp->database, remote_ps_data);
		set_ps_display(psbuf, false);

		/*
		 * Initialize per session context
		 */
		pool_init_session_context(frontend, backend);

		/* Mark this connection pool is connected from frontend */
		pool_coninfo_set_frontend_connected(pool_get_process_context()->proc_id, pool_pool_index());

		/* query process loop */
		for (;;)
		{
			POOL_STATUS status;

			status = pool_process_query(frontend, backend, 0);

			sp = MASTER_CONNECTION(backend)->sp;

			switch (status)
			{
				/* client exits */
				case POOL_END:
					/*
					 * do not cache connection if:
					 * pool_config->connection_cahe == 0 or
					 * database name is template0, template1, postgres or regression
					 */
					if (pool_config->connection_cache == 0 ||
						!strcmp(sp->database, "template0") ||
						!strcmp(sp->database, "template1") ||
						!strcmp(sp->database, "postgres") ||
						!strcmp(sp->database, "regression"))
					{
						reset_connection();
						pool_close(frontend);
						pool_send_frontend_exits(backend);
						pool_discard_cp(sp->user, sp->database, sp->major);
					}
					else
					{
						POOL_STATUS status1;

						/* send reset request to backend */
						status1 = pool_process_query(frontend, backend, 1);
						pool_close(frontend);

						/* if we detect errors on resetting connection, we need to discard
						 * this connection since it might be in unknown status
						 */
						if (status1 != POOL_CONTINUE)
						{
							pool_debug("error in resetting connections. discarding connection pools...");
							pool_send_frontend_exits(backend);
							pool_discard_cp(sp->user, sp->database, sp->major);
						}
						else
							pool_connection_pool_timer(backend);
					}
					break;

				/* error occurred. discard backend connection pool
                   and disconnect connection to the frontend */
				case POOL_ERROR:
					pool_log("do_child: exits with status 1 due to error");
					child_exit(1);
					break;

				/* fatal error occurred. just exit myself... */
				case POOL_FATAL:
					notice_backend_error(1);
					child_exit(1);
					break;

				/* not implemented yet */
				case POOL_IDLE:
					do_accept(unix_fd, inet_fd, &timeout);
					pool_debug("accept while idle");
					break;

				default:
					break;
			}

			if (status != POOL_CONTINUE)
				break;
		}

		/* Destroy session context */
		pool_session_context_destroy();

		/* Mark this connection pool is not connected from frontend */
		pool_coninfo_unset_frontend_connected(pool_get_process_context()->proc_id, pool_pool_index());

		accepted = 0;
		connection_count_down();

		timeout.tv_sec = pool_config->child_life_time;
		timeout.tv_usec = 0;

		/* increment queries counter if necessary */
		if ( pool_config->child_max_connections > 0 )
			connections_count++;

		/* check if maximum connections count for this child reached */
		if ( ( pool_config->child_max_connections > 0 ) &&
			( connections_count >= pool_config->child_max_connections ) )
		{
			pool_log("child exiting, %d connections reached", pool_config->child_max_connections);
			send_frontend_exits();
			child_exit(2);
		}
	}
	child_exit(0);
}
Exemplo n.º 19
0
/*
* perform accept() and return new fd
*/
static POOL_CONNECTION *do_accept(int unix_fd, int inet_fd, struct timeval *timeout)
{
    fd_set	readmask;
    int fds;
	int save_errno;

	SockAddr saddr;
	int fd = 0;
	int afd;
	int inet = 0;
	POOL_CONNECTION *cp;
#ifdef ACCEPT_PERFORMANCE
	struct timeval now1, now2;
	static long atime;
	static int cnt;
#endif
	struct timeval *timeoutval;
	struct timeval tv1, tv2, tmback = {0, 0};

	set_ps_display("wait for connection request", false);

	/* Destroy session context for just in case... */
	pool_session_context_destroy();

	FD_ZERO(&readmask);
	FD_SET(unix_fd, &readmask);
	if (inet_fd)
		FD_SET(inet_fd, &readmask);

	if (timeout->tv_sec == 0 && timeout->tv_usec == 0)
		timeoutval = NULL;
	else
	{
		timeoutval = timeout;
		tmback.tv_sec = timeout->tv_sec;
		tmback.tv_usec = timeout->tv_usec;
		gettimeofday(&tv1, NULL);

#ifdef DEBUG
		pool_log("before select = {%d, %d}", timeoutval->tv_sec, timeoutval->tv_usec);
		pool_log("g:before select = {%d, %d}", tv1.tv_sec, tv1.tv_usec);
#endif
	}

	fds = select(Max(unix_fd, inet_fd)+1, &readmask, NULL, NULL, timeoutval);

	save_errno = errno;
	/* check backend timer is expired */
	if (backend_timer_expired)
	{
		pool_backend_timer();
		backend_timer_expired = 0;
	}

	/*
	 * following code fragment computes remaining timeout val in a
	 * portable way. Linux does this automatically but other platforms do not.
	 */
	if (timeoutval)
	{
		gettimeofday(&tv2, NULL);

		tmback.tv_usec -= tv2.tv_usec - tv1.tv_usec;
		tmback.tv_sec -= tv2.tv_sec - tv1.tv_sec;

		if (tmback.tv_usec < 0)
		{
			tmback.tv_sec--;
			if (tmback.tv_sec < 0)
			{
				timeout->tv_sec = 0;
				timeout->tv_usec = 0;
			}
			else
			{
				tmback.tv_usec += 1000000;
				timeout->tv_sec = tmback.tv_sec;
				timeout->tv_usec = tmback.tv_usec;
			}
		}
#ifdef DEBUG
		pool_log("g:after select = {%d, %d}", tv2.tv_sec, tv2.tv_usec);
		pool_log("after select = {%d, %d}", timeout->tv_sec, timeout->tv_usec);
#endif
	}

	errno = save_errno;

	if (fds == -1)
	{
		if (errno == EAGAIN || errno == EINTR)
			return NULL;

		pool_error("select() failed. reason %s", strerror(errno));
		return NULL;
	}

	/* timeout */
	if (fds == 0)
	{
		return NULL;
	}

	if (FD_ISSET(unix_fd, &readmask))
	{
		fd = unix_fd;
	}

	if (FD_ISSET(inet_fd, &readmask))
	{
		fd = inet_fd;
		inet++;
	}

	/*
	 * Note that some SysV systems do not work here. For those
	 * systems, we need some locking mechanism for the fd.
	 */
	memset(&saddr, 0, sizeof(saddr));
	saddr.salen = sizeof(saddr.addr);

#ifdef ACCEPT_PERFORMANCE
	gettimeofday(&now1,0);
#endif

 retry_accept:

	/* wait if recovery is started */
	while (*InRecovery == 1)
	{
		pause();
	}

	afd = accept(fd, (struct sockaddr *)&saddr.addr, &saddr.salen);

	save_errno = errno;
	/* check backend timer is expired */
	if (backend_timer_expired)
	{
		pool_backend_timer();
		backend_timer_expired = 0;
	}
	errno = save_errno;
	if (afd < 0)
	{
		if (errno == EINTR && *InRecovery)
			goto retry_accept;

		/*
		 * "Resource temporarily unavailable" (EAGAIN or EWOULDBLOCK)
		 * can be silently ignored. And EINTR can be ignored.
		 */
		if (errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR)
			pool_error("accept() failed. reason: %s", strerror(errno));
		return NULL;
	}
#ifdef ACCEPT_PERFORMANCE
	gettimeofday(&now2,0);
	atime += (now2.tv_sec - now1.tv_sec)*1000000 + (now2.tv_usec - now1.tv_usec);
	cnt++;
	if (cnt % 100 == 0)
	{
		pool_log("cnt: %d atime: %ld", cnt, atime);
	}
#endif

	/* reload config file */
	if (got_sighup)
	{
		pool_get_config(get_config_file_name(), RELOAD_CONFIG);
		if (pool_config->enable_pool_hba)
		{
			load_hba(get_hba_file_name());
			if (strcmp("", pool_config->pool_passwd))
				pool_reopen_passwd_file();
		}
		if (pool_config->parallel_mode)
			pool_memset_system_db_info(system_db_info->info);
		got_sighup = 0;
	}

	connection_count_up();
	accepted = 1;

	if (pool_config->parallel_mode)
	{
		/*
		 * do not accept new connection if any of DB node or SystemDB is down when operating in
		 * parallel mode
		 */
		int i;

		for (i=0;i<NUM_BACKENDS;i++)
		{
			if (BACKEND_INFO(i).backend_status == CON_DOWN || SYSDB_STATUS == CON_DOWN)
			{
				StartupPacket *sp;
				char *msg = "pgpool is not available in parallel query mode";

				if (SYSDB_STATUS == CON_DOWN)
					pool_log("Cannot accept() new connection. SystemDB is down");
				else
					pool_log("Cannot accept() new connection. %d th backend is down", i);

				if ((cp = pool_open(afd)) == NULL)
				{
					close(afd);
					child_exit(1);
				}

				sp = read_startup_packet(cp);
				if (sp == NULL)
				{
					/* failed to read the startup packet. return to the accept() loop */
					pool_close(cp);
					child_exit(1);
				}

				pool_debug("do_accept: send error message to frontend");

				if (sp->major == PROTO_MAJOR_V3)
				{
					char buf[256];

					if (SYSDB_STATUS == CON_DOWN)
						snprintf(buf, sizeof(buf), "SystemDB is down");
					else
						snprintf(buf, sizeof(buf), "%d th backend is down", i);

					pool_send_error_message(cp, sp->major, "08S01",
											msg,
											buf,
											((SYSDB_STATUS == CON_DOWN) ? "repair the SystemDB and restart pgpool"
											                           : "repair the backend and restart pgpool"),
											__FILE__,
											__LINE__);
				}
				else
				{
					pool_send_error_message(cp, sp->major,
											0,
											msg,
											"",
											"",
											"",
											0);
				}
				pool_close(cp);
				child_exit(1);
			}
		}
	}
	else
	{
		/*
		 * do not accept new connection if all DB nodes are down when operating in
		 * non parallel mode
		 */
		int i;
		int found = 0;

		for (i=0;i<NUM_BACKENDS;i++)
		{
			if (VALID_BACKEND(i))
			{
				found = 1;
			}
		}
		if (found == 0)
		{
			pool_log("Cannot accept() new connection. all backends are down");
			child_exit(1);
		}
	}

	pool_debug("I am %d accept fd %d", getpid(), afd);

	pool_getnameinfo_all(&saddr, remote_host, remote_port);
	snprintf(remote_ps_data, sizeof(remote_ps_data),
			 remote_port[0] == '\0' ? "%s" : "%s(%s)",
			 remote_host, remote_port);

	set_ps_display("accept connection", false);

	/* log who is connecting */
	if (pool_config->log_connections)
	{
		pool_log("connection received: host=%s%s%s",
				 remote_host, remote_port[0] ? " port=" : "", remote_port);
	}

	/* set NODELAY and KEEPALIVE options if INET connection */
	if (inet)
	{
		int on = 1;

		if (setsockopt(afd, IPPROTO_TCP, TCP_NODELAY,
					   (char *) &on,
					   sizeof(on)) < 0)
		{
			pool_error("do_accept: setsockopt() failed: %s", strerror(errno));
			close(afd);
			return NULL;
		}
		if (setsockopt(afd, SOL_SOCKET, SO_KEEPALIVE,
					   (char *) &on,
					   sizeof(on)) < 0)
		{
			pool_error("do_accept: setsockopt() failed: %s", strerror(errno));
			close(afd);
			return NULL;
		}
	}

	if ((cp = pool_open(afd)) == NULL)
	{
		close(afd);
		return NULL;
	}

	/* save ip address for hba */
	memcpy(&cp->raddr, &saddr, sizeof(SockAddr));
	if (cp->raddr.addr.ss_family == 0)
		cp->raddr.addr.ss_family = AF_UNIX;

	return cp;
}
Exemplo n.º 20
0
/*
 * Reuse existing connection
 */
static bool connect_using_existing_connection(POOL_CONNECTION *frontend, 
											  POOL_CONNECTION_POOL *backend,
											  StartupPacket *sp)
{
	int i, freed = 0;
	/*
	 * Save startup packet info
	 */
	for (i = 0; i < NUM_BACKENDS; i++)
	{
		if (VALID_BACKEND(i))
		{
			if (!freed)
			{
				pool_free_startup_packet(backend->slots[i]->sp);
				freed = 1;
			}
			backend->slots[i]->sp = sp;
		}
	}

	/* Reuse existing connection to backend */

	if (pool_do_reauth(frontend, backend))
	{
		pool_close(frontend);
		connection_count_down();
		return false;
	}

	if (MAJOR(backend) == 3)
	{
		char command_buf[1024];

		/* If we have received application_name in the start up
		 * packet, we send SET command to backend. Also we add or
		 * replace existing application_name data.
		 */
		if (sp->application_name)
		{
			snprintf(command_buf, sizeof(command_buf), "SET application_name TO '%s'", sp->application_name);

			for (i=0;i<NUM_BACKENDS;i++)
			{
				if (VALID_BACKEND(i))
					if (do_command(frontend, CONNECTION(backend, i),
							   command_buf, MAJOR(backend),
								   MASTER_CONNECTION(backend)->pid,
								   MASTER_CONNECTION(backend)->key, 0) != POOL_CONTINUE)
					{
						pool_error("connect_using_existing_connection: do_command failed. command: %s", command_buf);
						return false;
					}
			}

			pool_add_param(&MASTER(backend)->params, "application_name", sp->application_name);
		}

		if (send_params(frontend, backend))
		{
			pool_close(frontend);
			connection_count_down();
			return false;
		}
	}

	/* Send ReadyForQuery to frontend */
	pool_write(frontend, "Z", 1);

	if (MAJOR(backend) == 3)
	{
		int len;
		char tstate;

		len = htonl(5);
		pool_write(frontend, &len, sizeof(len));
		tstate = TSTATE(backend, MASTER_NODE_ID);
		pool_write(frontend, &tstate, 1);
	}

	if (pool_flush(frontend) < 0)
	{
		pool_close(frontend);
		connection_count_down();
		return false;
	}
	return true;
}
Exemplo n.º 21
0
/*
 * process cancel request
 */
void cancel_request(CancelPacket *sp)
{
	int	len;
	int fd;
	POOL_CONNECTION *con;
	int i,j,k;
	ConnectionInfo *c = NULL;
	CancelPacket cp;
	bool found = false;

	pool_debug("Cancel request received");

	/* look for cancel key from shmem info */
	for (i=0;i<pool_config->num_init_children;i++)
	{
		for (j=0;j<pool_config->max_pool;j++)
		{
			for (k=0;k<NUM_BACKENDS;k++)
			{
				c = pool_coninfo(i, j, k);
				pool_debug("con_info: address:%p database:%s user:%s pid:%d key:%d i:%d",
						   c, c->database, c->user, ntohl(c->pid), ntohl(c->key),i);

				if (c->pid == sp->pid && c->key == sp->key)
				{
					pool_debug("found pid:%d key:%d i:%d",ntohl(c->pid), ntohl(c->key),i);
					c = pool_coninfo(i, j, 0);
					found = true;
					goto found;
				}
			}
		}
	}

 found:
	if (!found)
	{
		pool_error("cancel_request: invalid cancel key: pid:%d key:%d",ntohl(sp->pid), ntohl(sp->key));
		return;	/* invalid key */
	}

	for (i=0;i<NUM_BACKENDS;i++,c++)
	{
		if (!VALID_BACKEND(i))
			continue;

		if (*(BACKEND_INFO(i).backend_hostname) == '/')
			fd = connect_unix_domain_socket(i, TRUE);
		else
			fd = connect_inet_domain_socket(i, TRUE);

		if (fd < 0)
		{
			pool_error("Could not create socket for sending cancel request for backend %d", i);
			return;
		}

		con = pool_open(fd);
		if (con == NULL)
			return;

		len = htonl(sizeof(len) + sizeof(CancelPacket));
		pool_write(con, &len, sizeof(len));

		cp.protoVersion = sp->protoVersion;
		cp.pid = c->pid;
		cp.key = c->key;

		pool_log("cancel_request: canceling backend pid:%d key: %d", ntohl(cp.pid),ntohl(cp.key));

		if (pool_write_and_flush(con, &cp, sizeof(CancelPacket)) < 0)
			pool_error("Could not send cancel request packet for backend %d", i);

		pool_close(con);

		/*
		 * this is needed to ensure that the next DB node executes the
		 * query supposed to be canceled.
		 */
		sleep(1);
	}
}