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);
}
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);
}
/*
* 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);
pool_free_startup_packet(sp);
goto retry_startup;
}
/* this should run before ClientAuthentication */
pool_prestogres_set_defaults(sp);
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);
/* ClientAuthentication can overwrite database and user */
if (strcmp(sp->database, frontend->database) || strcmp(sp->user, frontend->username)) {
free(sp->database);
sp->database = strdup(frontend->database);
free(sp->user);
sp->user = strdup(frontend->username);
if (frontend->username == NULL)
{
pool_error("do_child: strdup failed: %s\n", strerror(errno));
child_exit(1);
}
rebuild_startup_packet(sp);
}
}
/*
* 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);
}
/*
* 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;
}
