예제 #1
0
/*
 * Increment local session id
 */
void pool_incremnet_local_session_id(void)
{
	POOL_PROCESS_CONTEXT *p = pool_get_process_context();

	if (!p)
		ereport(ERROR,
				(errmsg("failed to get process context")));

	p->local_session_id++;
}
예제 #2
0
/*
* initialize connection pools. this should be called once at the startup.
*/
int pool_init_cp(void)
{
	int i;

	pool_connection_pool = (POOL_CONNECTION_POOL *)malloc(sizeof(POOL_CONNECTION_POOL)*pool_config->max_pool);
	if (pool_connection_pool == NULL)
	{
		pool_error("pool_init_cp: malloc() failed");
		return -1;
	}
	memset(pool_connection_pool, 0, sizeof(POOL_CONNECTION_POOL)*pool_config->max_pool);

	for (i = 0; i < pool_config->max_pool; i++)
	{
		pool_connection_pool[i].info = pool_coninfo(pool_get_process_context()->proc_id, i, 0);
		memset(pool_connection_pool[i].info, 0, sizeof(ConnectionInfo) * MAX_NUM_BACKENDS);
	}
	return 0;
}
예제 #3
0
/*
 * Initialize per session context
 */
void pool_init_session_context(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *backend)
{
	session_context = &session_context_d;

	/* Get Process context */
	session_context->process_context = pool_get_process_context();
	if (!session_context->process_context)
	{
		pool_error("pool_init_session_context: cannot get process context");
		return;
	}

	/* Set connection info */
	session_context->frontend = frontend;
	session_context->backend = backend;

	/* Initialize query context */
	session_context->query_context = NULL;

	/* Initialize local session id */
	pool_incremnet_local_session_id();

	/* Initialize sent message list */
	init_sent_message_list();

	/* Create memory context */
	session_context->memory_context = pool_memory_create(PREPARE_BLOCK_SIZE);

	/* Choose load balancing node if necessary */
	if (pool_config->load_balance_mode)
	{
		ProcessInfo *process_info = pool_get_my_process_info();
		if (!process_info)
		{
			pool_error("pool_init_session_context: pool_get_my_process_info failed");
			return;
		}

		session_context->load_balance_node_id = 
			process_info->connection_info->load_balancing_node =
			select_load_balancing_node();

		pool_debug("selected load balancing node: %d", backend->info->load_balancing_node);
	}

	/* Unset query is in progress */
	pool_unset_query_in_progress();

	/* The command in progress has not succeeded yet */
	pool_unset_command_success();

	/* We don't have a write query in this transaction yet */
	pool_unset_writing_transaction();

	/* Error doesn't occur in this transaction yet */
	pool_unset_failed_transaction();

	/* Forget transaction isolation mode */
	pool_unset_transaction_isolation();

	/* We don't skip reading from backends */
	pool_unset_skip_reading_from_backends();

	/* Backends have not ignored messages yet */
	pool_unset_ignore_till_sync();

	/* Initialize where to send map for PREPARE statements */
#ifdef NOT_USED
	memset(&session_context->prep_where, 0, sizeof(session_context->prep_where));
	session_context->prep_where.nelem = POOL_MAX_PREPARED_STATEMENTS;
#endif /* NOT_USED */
	/* Reset flag to indicate difference in number of affected tuples
	 * in UPDATE/DELETE.
	 */
	session_context->mismatch_ntuples = false;

	if (pool_config->memory_cache_enabled)
	{
		session_context->query_cache_array = pool_create_query_cache_array();
		session_context->num_selects = 0;
	}
}
예제 #4
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);
}