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MXS-1493: Collect slave heartbeats

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The slave heartbeat count and period are collected from the SHOW ALL
SLAVES STATUS output. This, in addition to the relay log position, is used
to calculate the point in time when a slave has last interacted with the
master.

By using this timestamp, the monitor can enforce a minimum "timeout" for
the master before a failover is performed.
This commit is contained in:
Markus Mäkelä
2017-10-26 11:26:58 +03:00
parent 48a15368d0
commit 26b47d0b90
1 changed files with 31 additions and 2 deletions
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33
server/modules/monitor/mysqlmon/mysql_mon.cc
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@ -46,6 +46,8 @@
#define MARIA10_STATUS_IO_RUNNING 12
#define MARIA10_STATUS_SQL_RUNNING 13
#define MARIA10_STATUS_MASTER_ID 41
#define MARIA10_STATUS_HEARTBEATS 55
#define MARIA10_STATUS_HEARTBEAT_PERIOD 56
/** Column positions for SHOW SLAVE HOSTS */
#define SLAVE_HOSTS_SERVER_ID 0
@ -575,7 +577,10 @@ typedef struct mysql_server_info
char *binlog_name; /**< Binlog name from SHOW SLAVE STATUS */
bool binlog_relay; /** Server is a Binlog Relay */
int n_slaves_configured; /**< Number of configured slave connections*/
int n_slaves_running; /**< Number of running slave connections */
int n_slaves_running; /**< Number of running slave connections */
int slave_heartbeats; /**< Number of received heartbeats*/
double heartbeat_period; /**< The time interval between heartbeats */
time_t latest_event; /**< Time when latest event was received from the master */
} MYSQL_SERVER_INFO;
void* info_copy_func(const void *val)
@ -1018,12 +1023,20 @@ static bool do_show_slave_status(MYSQL_SERVER_INFO* serv_info, MXS_MONITORED_SER
{
/** Only check binlog name for the first running slave */
char *binlog_name = MXS_STRDUP(row[i_binlog_name]);
uint64_t binlog_pos = atol(row[i_binlog_pos]);
if (binlog_name)
{
if (strcmp(binlog_name, serv_info->binlog_name) != 0 ||
binlog_pos != serv_info->binlog_pos)
{
// IO thread is reading events from the master
serv_info->latest_event = time(NULL);
}
MXS_FREE(serv_info->binlog_name);
serv_info->binlog_name = binlog_name;
serv_info->binlog_pos = atol(row[i_binlog_pos]);
serv_info->binlog_pos = binlog_pos;
}
}
@ -1045,6 +1058,21 @@ static bool do_show_slave_status(MYSQL_SERVER_INFO* serv_info, MXS_MONITORED_SER
}
}
if (server_version == MYSQL_SERVER_VERSION_100)
{
ss_debug(MYSQL_FIELD* f = mysql_fetch_fields(result));
ss_dassert(strcmp(f[MARIA10_STATUS_HEARTBEATS].name, "Slave_received_heartbeats") == 0);
ss_dassert(strcmp(f[MARIA10_STATUS_HEARTBEAT_PERIOD].name, "Slave_heartbeat_period") == 0);
int heartbeats = atoi(row[MARIA10_STATUS_HEARTBEATS]);
if (serv_info->slave_heartbeats < heartbeats)
{
serv_info->latest_event = time(NULL);
serv_info->slave_heartbeats = heartbeats;
serv_info->heartbeat_period = atof(row[MARIA10_STATUS_HEARTBEAT_PERIOD]);
}
}
nconfigured++;
row = mysql_fetch_row(result);
}
@ -1058,6 +1086,7 @@ static bool do_show_slave_status(MYSQL_SERVER_INFO* serv_info, MXS_MONITORED_SER
serv_info->slave_sql = false;
serv_info->binlog_pos = 0;
serv_info->binlog_name[0] = '\0';
serv_info->slave_heartbeats = 0;
}
serv_info->master_id = master_id;