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/*
* $Header$
*
* Handles watchdog connection, and protocol communication with pgpool-II
*
* pgpool: a language independent connection pool server for PostgreSQL
* written by Tatsuo Ishii
*
* Copyright (c) 2003-2013 PgPool Global Development Group
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that the above copyright notice appear in all
* copies and that both that copyright notice and this permission
* notice appear in supporting documentation, and that the name of the
* author not be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission. The author makes no representations about the
* suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
*/
#include <pthread.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <netdb.h>
#include "pool.h"
#include "pool_config.h"
#include "watchdog.h"
#include "wd_ext.h"
#include "libpq-fe.h"
int is_wd_lifecheck_ready(void);
int wd_lifecheck(void);
int wd_ping_pgpool(WdInfo * pgpool);
static void * thread_ping_pgpool(void * arg);
static PGconn * create_conn(char * hostname, int port);
static int pgpool_down(WdInfo * pool);
static void check_pgpool_status(void);
static void check_pgpool_status_by_query(void);
static void check_pgpool_status_by_hb(void);
static int ping_pgpool(PGconn * conn);
static int is_parent_alive(void);
int
is_wd_lifecheck_ready(void)
{
int rtn = WD_OK;
WdInfo * p = WD_List;
int i = 0;
while (p->status != WD_END)
{
/* query mode */
if (!strcmp(pool_config->wd_lifecheck_method, MODE_QUERY))
{
if (wd_ping_pgpool(p) == WD_NG)
{
pool_debug("is_wd_lifecheck_ready: pgpool %d (%s:%d) has not started yet",
i, p->hostname, p->pgpool_port);
rtn = WD_NG;
}
}
/* heartbeat mode */
else if (!strcmp(pool_config->wd_lifecheck_method, MODE_HEARTBEAT))
{
if (p == WD_List)
{
p++;
i++;
continue;
}
if (!WD_TIME_ISSET(p->hb_last_recv_time) ||
!WD_TIME_ISSET(p->hb_send_time))
{
pool_debug("is_wd_lifecheck_ready: pgpool %d (%s:%d) has not send the heartbeat signal yet",
i, p->hostname, p->pgpool_port);
rtn = WD_NG;
}
}
/* otherwise */
else
{
pool_error("is_wd_lifecheck_ready: unkown watchdog mode %s",
pool_config->wd_lifecheck_method);
return WD_NG;
}
p ++;
i ++;
}
return rtn;
}
/*
* Check if pgpool is living
*/
int
wd_lifecheck(void)
{
struct timeval tv;
/* I'm in down.... */
if (WD_MYSELF->status == WD_DOWN)
{
pool_error("wd_lifecheck: watchdog status is DOWN. You need to restart pgpool");
return WD_NG;
}
/* set startup time */
gettimeofday(&tv, NULL);
/* check upper connection */
if (strlen(pool_config->trusted_servers) &&
wd_is_upper_ok(pool_config->trusted_servers) != WD_OK)
{
pool_error("wd_lifecheck: failed to connect to any trusted servers");
if (WD_MYSELF->status == WD_MASTER &&
strlen(pool_config->delegate_IP) != 0)
{
wd_IP_down();
}
wd_set_myself(&tv, WD_DOWN);
wd_notice_server_down();
return WD_NG;
}
/* skip lifecheck during recovery execution */
if (*InRecovery != RECOVERY_INIT)
{
return WD_OK;
}
/* check and update pgpool status */
check_pgpool_status();
return WD_OK;
}
/*
* check and update pgpool status
*/
static void
check_pgpool_status()
{
/* query mode */
if (!strcmp(pool_config->wd_lifecheck_method, MODE_QUERY))
{
check_pgpool_status_by_query();
}
/* heartbeat mode */
else if (!strcmp(pool_config->wd_lifecheck_method, MODE_HEARTBEAT))
{
check_pgpool_status_by_hb();
}
}
static void
check_pgpool_status_by_hb(void)
{
int cnt;
WdInfo * p = WD_List;
struct timeval tv;
gettimeofday(&tv, NULL);
cnt = 0;
while (p->status != WD_END)
{
pool_debug("check_pgpool_status_by_hb: checking pgpool %d (%s:%d)",
cnt, p->hostname, p->pgpool_port);
/* about myself */
if (p == WD_MYSELF)
{
/* parent is dead so it's orphan.... */
if (is_parent_alive() == WD_NG && WD_MYSELF->status != WD_DOWN)
{
pool_debug("check_pgpool_status_by_hb: NG; the main pgpool process does't exist.");
pool_log("check_pgpool_status_by_hb: lifecheck failed. pgpool %d (%s:%d) seems not to be working",
cnt, p->hostname, p->pgpool_port);
wd_set_myself(&tv, WD_DOWN);
wd_notice_server_down();
}
/* otherwise, the parent would take care of children. */
else
{
pool_debug("check_pgpool_status_by_hb: OK; status %d", p->status);
}
}
/* about other pgpools, check the latest heartbeat. */
else
{
if (p->status == WD_DOWN)
{
pool_log("check_pgpool_status_by_hb: pgpool %d (%s:%d) is in down status",
cnt, p->hostname, p->pgpool_port);
}
else if (wd_check_heartbeat(p) == WD_NG)
{
pool_debug("check_pgpool_status_by_hb: NG; status %d", p->status);
pool_log("check_pgpool_status_by_hb: lifecheck failed. pgpool %d (%s:%d) seems not to be working",
cnt, p->hostname, p->pgpool_port);
if (p->status != WD_DOWN)
pgpool_down(p);
}
else
{
pool_debug("check_pgpool_status_by_hb: OK; status %d", p->status);
}
}
p++;
cnt++;
if (cnt >= MAX_WATCHDOG_NUM)
{
pool_error("check_pgpool_status_by_hb: pgpool num is out of range(%d)",cnt);
break;
}
}
}
static void
check_pgpool_status_by_query(void)
{
WdInfo * p = WD_List;
struct timeval tv;
pthread_attr_t attr;
pthread_t thread[MAX_WATCHDOG_NUM];
WdPgpoolThreadArg thread_arg[MAX_WATCHDOG_NUM];
int rc;
int i,cnt;
/* set startup time */
gettimeofday(&tv, NULL);
/* thread init */
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
/* send queries to all pgpools using threads */
cnt = 0;
while (p->status != WD_END)
{
if (p->status != WD_DOWN)
{
thread_arg[cnt].conn = create_conn(p->hostname, p->pgpool_port);
rc = pthread_create(&thread[cnt], &attr, thread_ping_pgpool, (void*)&thread_arg[cnt]);
}
p ++;
cnt ++;
if (cnt >= MAX_WATCHDOG_NUM)
{
pool_error("check_pgpool_status_by_query: pgpool num is out of range(%d)",cnt);
break;
}
}
pthread_attr_destroy(&attr);
/* check results of queries */
p = WD_List;
for (i = 0; i < cnt; )
{
int result;
pool_debug("check_pgpool_status_by_query: checking pgpool %d (%s:%d)",
i, p->hostname, p->pgpool_port);
if (p->status == WD_DOWN)
{
pool_log("check_pgpool_status_by_query: pgpool %d (%s:%d) is in down status",
i, p->hostname, p->pgpool_port);
i++;
p++;
continue;
}
else
{
rc = pthread_join(thread[i], (void **)&result);
if ((rc != 0) && (errno == EINTR))
{
usleep(100);
continue;
}
}
if (result == WD_OK)
{
pool_debug("check_pgpool_status_by_query: OK; status: %d", p->status);
/* life point init */
p->life = pool_config->wd_life_point;
}
else
{
pool_debug("check_pgpool_status_by_query: NG; status: %d life:%d", p->status, p->life);
if (p->life > 0)
{
p->life --;
}
/* pgpool goes down */
if (p->life <= 0)
{
pool_log("check_pgpool_status_by_query: lifecheck failed %d times. pgpool %d (%s:%d) seems not to be working",
pool_config->wd_life_point, i, p->hostname, p->pgpool_port);
/* It's me! */
if ((i == 0) &&
(WD_MYSELF->status != WD_DOWN))
{
wd_set_myself(&tv, WD_DOWN);
wd_notice_server_down();
}
/* It's other pgpool */
else if (p->status != WD_DOWN)
pgpool_down(p);
}
}
i++;
p++;
}
}
/*
* Thread function to send lifecheck query to pgpool
* Used in wd_lifecheck.
*/
static void *
thread_ping_pgpool(void * arg)
{
uintptr_t rtn;
WdPgpoolThreadArg * thread_arg;
PGconn * conn;
thread_arg = (WdPgpoolThreadArg *)arg;
conn = thread_arg->conn;
rtn = (uintptr_t)ping_pgpool(conn);
pthread_exit((void *)rtn);
}
/*
* Create connection to pgpool
*/
static PGconn *
create_conn(char * hostname, int port)
{
static char conninfo[1024];
PGconn *conn;
if (strlen(pool_config->wd_lifecheck_dbname) == 0)
{
pool_error("create_conn: wd_lifecheck_dbname is empty");
return NULL;
}
if (strlen(pool_config->wd_lifecheck_user) == 0)
{
pool_error("create_conn: wd_lifecheck_user is empty");
return NULL;
}
snprintf(conninfo,sizeof(conninfo),
"host='%s' port='%d' dbname='%s' user='%s' password='%s' connect_timeout='%d'",
hostname,
port,
pool_config->wd_lifecheck_dbname,
pool_config->wd_lifecheck_user,
pool_config->wd_lifecheck_password,
pool_config->wd_interval / 2 + 1);
conn = PQconnectdb(conninfo);
if (PQstatus(conn) != CONNECTION_OK)
{
pool_debug("create_conn: Connection to database failed: %s", PQerrorMessage(conn));
PQfinish(conn);
return NULL;
}
return conn;
}
/* handle other pgpool's down */
static int
pgpool_down(WdInfo * pool)
{
int rtn = WD_OK;
WD_STATUS prev_status;
pool_log("pgpool_down: %s:%d is going down",
pool->hostname, pool->pgpool_port);
prev_status = pool->status;
pool->status = WD_DOWN;
/* the active pgpool goes down and I'm sandby pgpool */
if (prev_status == WD_MASTER && WD_MYSELF->status == WD_NORMAL)
{
if (wd_am_I_oldest() == WD_OK)
{
pool_log("pgpool_down: I'm oldest so standing for master");
/* stand for master */
rtn = wd_stand_for_master();
if (rtn == WD_OK)
{
/* win */
wd_escalation();
}
else
{
/* rejected by others */
pool->status = prev_status;
}
}
}
return rtn;
}
/*
* Check if pgpool is alive using heartbeat signal.
*/
int
wd_check_heartbeat(WdInfo * pgpool)
{
int interval;
struct timeval tv;
if (!WD_TIME_ISSET(pgpool->hb_last_recv_time) ||
!WD_TIME_ISSET(pgpool->hb_send_time))
{
pool_debug("wd_check_heartbeat: pgpool (%s:%d) was restarted and has not send the heartbeat signal yet",
pgpool->hostname, pgpool->pgpool_port);
return WD_OK;
}
gettimeofday(&tv, NULL);
interval = WD_TIME_DIFF_SEC(tv, pgpool->hb_last_recv_time);
pool_debug("wd_check_heartbeat: the latest heartbeat from %s:%d received %d seconds ago",
pgpool->hostname, pgpool->pgpool_port, interval);
if (interval > pool_config->wd_heartbeat_deadtime)
return WD_NG;
else
return WD_OK;
}
/*
* Check if pgpool can accept the lifecheck query.
*/
int
wd_ping_pgpool(WdInfo * pgpool)
{
int rtn;
PGconn * conn;
conn = create_conn(pgpool->hostname, pgpool->pgpool_port);
rtn = ping_pgpool(conn);
return rtn;
}
/* inner function for issueing lifecheck query */
static int
ping_pgpool(PGconn * conn)
{
int rtn = WD_NG;
int status = PGRES_FATAL_ERROR;
PGresult * res = (PGresult *)NULL;
if (!conn)
{
return WD_NG;
}
res = PQexec(conn, pool_config->wd_lifecheck_query );
status = PQresultStatus(res);
if (res != NULL)
{
PQclear(res);
}
if ((status != PGRES_NONFATAL_ERROR ) &&
(status != PGRES_FATAL_ERROR ))
{
rtn = WD_OK;
}
PQfinish(conn);
return rtn;
}
static int
is_parent_alive()
{
if (mypid == getppid())
return WD_OK;
else
return WD_NG;
}
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