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MaxScale/server/modules/monitor/mysql_mon.c
Markus Makela 0111df3767 Cleaned up the use of thread types 
The THREAD type was not used everywhere and pthread_t was used instead.
The thread creation function also returned the address of a stack allocated
value which isn't guaranteed to be usable.
2016-01-27 09:07:55 +02:00

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/*
* This file is distributed as part of the MariaDB Corporation MaxScale. It is free
* software: you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation,
* version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright MariaDB Corporation Ab 2013-2014
*/
/**
* @file mysql_mon.c - A MySQL replication cluster monitor
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/07/13 Mark Riddoch Initial implementation
* 11/07/13 Mark Riddoch Addition of code to check replication
* status
* 25/07/13 Mark Riddoch Addition of decrypt for passwords and
* diagnostic interface
* 20/05/14 Massimiliano Pinto Addition of support for MariadDB multimaster replication setup.
* New server field version_string is updated.
* 28/05/14 Massimiliano Pinto Added set Id and configuration options (setInverval)
* Parameters are now printed in diagnostics
* 03/06/14 Mark Ridoch Add support for maintenance mode
* 17/06/14 Massimiliano Pinto Addition of getServerByNodeId routine
* and first implementation for depth of replication for nodes.
* 23/06/14 Massimiliano Pinto Added replication consistency after replication tree computation
* 27/06/14 Massimiliano Pinto Added replication pending status in monitored server, storing there
* the status to update in server status field before
* starting the replication consistency check.
* This will also give routers a consistent "status" of all servers
* 28/08/14 Massimiliano Pinto Added detectStaleMaster feature: previous detected master will be used again, even if the replication is stopped.
* This means both IO and SQL threads are not working on slaves.
* This option is not enabled by default.
* 10/11/14 Massimiliano Pinto Addition of setNetworkTimeout for connect, read, write
* 18/11/14 Massimiliano Pinto One server only in configuration becomes master.
* servers=server1 must be present in mysql_mon and in router sections as well.
* 08/05/15 Markus Makela Added launchable scripts
* 17/10/15 Martin Brampton Change DCB callback to hangup
*
* @endverbatim
*/
#include <mysqlmon.h>
#include <dcb.h>
#include <modutil.h>
static void monitorMain(void *);
static char *version_str = "V1.4.0";
MODULE_INFO info =
{
MODULE_API_MONITOR,
MODULE_GA,
MONITOR_VERSION,
"A MySQL Master/Slave replication monitor"
};
static void *startMonitor(void *, void*);
static void stopMonitor(void *);
static void diagnostics(DCB *, void *);
static void defaultId(void *, unsigned long);
static MONITOR_SERVERS *getServerByNodeId(MONITOR_SERVERS *, long);
static MONITOR_SERVERS *getSlaveOfNodeId(MONITOR_SERVERS *, long);
static MONITOR_SERVERS *get_replication_tree(MONITOR *, int);
static void set_master_heartbeat(MYSQL_MONITOR *, MONITOR_SERVERS *);
static void set_slave_heartbeat(MONITOR *, MONITOR_SERVERS *);
static int add_slave_to_master(long *, int, long);
bool isMySQLEvent(monitor_event_t event);
void check_maxscale_schema_replication(MONITOR *monitor);
static bool report_version_err = true;
static const char* hb_table_name = "maxscale_schema.replication_heartbeat";
static MONITOR_OBJECT MyObject =
{
startMonitor,
stopMonitor,
diagnostics
};
/**
* Implementation of the mandatory version entry point
*
* @return version string of the module
*/
char *
version()
{
return version_str;
}
/**
* The module initialisation routine, called when the module
* is first loaded.
*/
void
ModuleInit()
{
MXS_NOTICE("Initialise the MySQL Monitor module %s.", version_str);
}
/**
* The module entry point routine. It is this routine that
* must populate the structure that is referred to as the
* "module object", this is a structure with the set of
* external entry points for this module.
*
* @return The module object
*/
MONITOR_OBJECT *
GetModuleObject()
{
return &MyObject;
}
/**
* Start the instance of the monitor, returning a handle on the monitor.
*
* This function creates a thread to execute the actual monitoring.
*
* @param arg The current handle - NULL if first start
* @param opt Configuration parameters
* @return A handle to use when interacting with the monitor
*/
static void *
startMonitor(void *arg, void* opt)
{
MONITOR* monitor = (MONITOR*) arg;
MYSQL_MONITOR *handle = (MYSQL_MONITOR*) monitor->handle;
CONFIG_PARAMETER* params = (CONFIG_PARAMETER*) opt;
bool have_events = false, script_error = false;
if (handle)
{
handle->shutdown = 0;
}
else
{
if ((handle = (MYSQL_MONITOR *) malloc(sizeof(MYSQL_MONITOR))) == NULL)
return NULL;
handle->shutdown = 0;
handle->id = config_get_gateway_id();
handle->replicationHeartbeat = 0;
handle->detectStaleMaster = 0;
handle->master = NULL;
handle->script = NULL;
handle->mysql51_replication = false;
memset(handle->events, false, sizeof(handle->events));
spinlock_init(&handle->lock);
}
while (params)
{
if (!strcmp(params->name, "detect_stale_master"))
handle->detectStaleMaster = config_truth_value(params->value);
else if (!strcmp(params->name, "detect_replication_lag"))
handle->replicationHeartbeat = config_truth_value(params->value);
else if (!strcmp(params->name, "script"))
{
if (externcmd_can_execute(params->value))
{
free(handle->script);
handle->script = strdup(params->value);
}
else
{
script_error = true;
}
}
else if (!strcmp(params->name, "events"))
{
if (mon_parse_event_string((bool*) & handle->events, sizeof(handle->events), params->value) != 0)
script_error = true;
else
have_events = true;
}
else if (!strcmp(params->name, "mysql51_replication"))
{
handle->mysql51_replication = config_truth_value(params->value);
}
params = params->next;
}
if (script_error)
{
MXS_ERROR("Errors were found in the script configuration parameters "
"for the monitor '%s'. The script will not be used.", monitor->name);
free(handle->script);
handle->script = NULL;
}
/** If no specific events are given, enable them all */
if (!have_events)
{
memset(handle->events, true, sizeof(handle->events));
}
if (thread_start(&handle->thread, monitorMain, monitor) == NULL)
{
MXS_ERROR("Failed to start monitor thread for monitor '%s'.", monitor->name);
}
return handle;
}
/**
* Stop a running monitor
*
* @param arg Handle on thr running monior
*/
static void
stopMonitor(void *arg)
{
MONITOR* mon = (MONITOR*) arg;
MYSQL_MONITOR *handle = (MYSQL_MONITOR *) mon->handle;
handle->shutdown = 1;
thread_wait(handle->thread);
}
/**
* Daignostic interface
*
* @param dcb DCB to print diagnostics
* @param arg The monitor handle
*/
static void diagnostics(DCB *dcb, void *arg)
{
MONITOR* mon = (MONITOR*) arg;
MYSQL_MONITOR *handle = (MYSQL_MONITOR *) mon->handle;
MONITOR_SERVERS *db;
char *sep;
switch (handle->status)
{
case MONITOR_RUNNING:
dcb_printf(dcb, "\tMonitor running\n");
break;
case MONITOR_STOPPING:
dcb_printf(dcb, "\tMonitor stopping\n");
break;
case MONITOR_STOPPED:
dcb_printf(dcb, "\tMonitor stopped\n");
break;
}
dcb_printf(dcb, "\tSampling interval:\t%lu milliseconds\n", mon->interval);
dcb_printf(dcb, "\tMaxScale MonitorId:\t%lu\n", handle->id);
dcb_printf(dcb, "\tReplication lag:\t%s\n", (handle->replicationHeartbeat == 1) ? "enabled" : "disabled");
dcb_printf(dcb, "\tDetect Stale Master:\t%s\n", (handle->detectStaleMaster == 1) ? "enabled" : "disabled");
dcb_printf(dcb, "\tConnect Timeout:\t%i seconds\n", mon->connect_timeout);
dcb_printf(dcb, "\tRead Timeout:\t\t%i seconds\n", mon->read_timeout);
dcb_printf(dcb, "\tWrite Timeout:\t\t%i seconds\n", mon->write_timeout);
dcb_printf(dcb, "\tMonitored servers: ");
db = mon->databases;
sep = "";
while (db)
{
dcb_printf(dcb,
"%s%s:%d",
sep,
db->server->name,
db->server->port);
sep = ", ";
db = db->next;
}
dcb_printf(dcb, "\n");
}
static inline void monitor_mysql100_db(MONITOR_SERVERS* database)
{
int isslave = 0;
MYSQL_RES* result;
MYSQL_ROW row;
if (mysql_query(database->con, "SHOW ALL SLAVES STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
int i = 0;
long master_id = -1;
if (mysql_field_count(database->con) < 42)
{
mysql_free_result(result);
MXS_ERROR("\"SHOW ALL SLAVES STATUS\" "
"returned less than the expected amount of columns. Expected 42 columns."
" MySQL Version: %s", version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[12], "Yes", 3) == 0
&& strncmp(row[13], "Yes", 3) == 0)
{
isslave += 1;
}
/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
* the replication tree, slaves ids will be added to master(s) and we will have at least the
* root master server.
* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
*/
if (strncmp(row[12], "Yes", 3) == 0)
{
/* get Master_Server_Id values */
master_id = atol(row[41]);
if (master_id == 0)
master_id = -1;
}
i++;
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
mysql_free_result(result);
/* If all configured slaves are running set this node as slave */
if (isslave > 0 && isslave == i)
{
isslave = 1;
}
else
{
isslave = 0;
}
}
/* Remove addition info */
monitor_clear_pending_status(database, SERVER_SLAVE_OF_EXTERNAL_MASTER);
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
/* Please note, the MASTER status and SERVER_SLAVE_OF_EXTERNAL_MASTER
* will be assigned in the monitorMain() via get_replication_tree() routine
*/
/* Set the Slave Role */
if (isslave)
{
monitor_set_pending_status(database, SERVER_SLAVE);
/* Avoid any possible stale Master state */
monitor_clear_pending_status(database, SERVER_MASTER);
}
else
{
/* Avoid any possible Master/Slave stale state */
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
}
}
static inline void monitor_mysql55_db(MONITOR_SERVERS* database)
{
bool isslave = false;
MYSQL_RES* result;
MYSQL_ROW row;
if (mysql_query(database->con, "SHOW SLAVE STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long master_id = -1;
if (mysql_field_count(database->con) < 40)
{
mysql_free_result(result);
MXS_ERROR("\"SHOW SLAVE STATUS\" "
"returned less than the expected amount of columns. Expected 40 columns."
" MySQL Version: %s", version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[10], "Yes", 3) == 0
&& strncmp(row[11], "Yes", 3) == 0)
{
isslave = 1;
}
/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
* the replication tree, slaves ids will be added to master(s) and we will have at least the
* root master server.
* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
*/
if (strncmp(row[10], "Yes", 3) == 0)
{
/* get Master_Server_Id values */
master_id = atol(row[39]);
if (master_id == 0)
master_id = -1;
}
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
mysql_free_result(result);
}
/* Remove addition info */
monitor_clear_pending_status(database, SERVER_SLAVE_OF_EXTERNAL_MASTER);
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
/* Please note, the MASTER status and SERVER_SLAVE_OF_EXTERNAL_MASTER
* will be assigned in the monitorMain() via get_replication_tree() routine
*/
/* Set the Slave Role */
if (isslave)
{
monitor_set_pending_status(database, SERVER_SLAVE);
/* Avoid any possible stale Master state */
monitor_clear_pending_status(database, SERVER_MASTER);
}
else
{
/* Avoid any possible Master/Slave stale state */
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
}
}
static inline void monitor_mysql51_db(MONITOR_SERVERS* database)
{
bool isslave = false;
MYSQL_RES* result;
MYSQL_ROW row;
if (mysql_query(database->con, "SHOW SLAVE STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
if (mysql_field_count(database->con) < 38)
{
mysql_free_result(result);
MXS_ERROR("\"SHOW SLAVE STATUS\" "
"returned less than the expected amount of columns. Expected 38 columns."
" MySQL Version: %s", version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[10], "Yes", 3) == 0
&& strncmp(row[11], "Yes", 3) == 0)
{
isslave = 1;
}
}
mysql_free_result(result);
}
/* Remove addition info */
monitor_clear_pending_status(database, SERVER_SLAVE_OF_EXTERNAL_MASTER);
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
/* Please note, the MASTER status and SERVER_SLAVE_OF_EXTERNAL_MASTER
* will be assigned in the monitorMain() via get_replication_tree() routine
*/
/* Set the Slave Role */
if (isslave)
{
monitor_set_pending_status(database, SERVER_SLAVE);
/* Avoid any possible stale Master state */
monitor_clear_pending_status(database, SERVER_MASTER);
}
else
{
/* Avoid any possible Master/Slave stale state */
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
}
}
/**
* Build the replication tree for a MySQL 5.1 cluster
*
* This function queries each server with SHOW SLAVE HOSTS to determine which servers
* have slaves replicating from them.
* @param mon Monitor
* @return Lowest server ID master in the monitor
*/
static MONITOR_SERVERS *build_mysql51_replication_tree(MONITOR *mon)
{
MONITOR_SERVERS* database = mon->databases;
MONITOR_SERVERS *ptr, *rval = NULL;
int i;
while (database)
{
bool ismaster = false;
MYSQL_RES* result;
MYSQL_ROW row;
int nslaves = 0;
if (database->con)
{
if (mysql_query(database->con, "SHOW SLAVE HOSTS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
if (mysql_field_count(database->con) < 4)
{
mysql_free_result(result);
MXS_ERROR("\"SHOW SLAVE HOSTS\" "
"returned less than the expected amount of columns. "
"Expected 4 columns."
" MySQL Version: %s", version_str);
return NULL;
}
if (mysql_num_rows(result) > 0)
{
ismaster = true;
while (nslaves < MONITOR_MAX_NUM_SLAVES && (row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
database->server->slaves[nslaves] = atol(row[0]);
nslaves++;
MXS_DEBUG("Found slave at %s:%s", row[1], row[2]);
}
database->server->slaves[nslaves] = 0;
}
mysql_free_result(result);
}
/* Set the Slave Role */
if (ismaster)
{
MXS_DEBUG("Master server found at %s:%d with %d slaves",
database->server->name,
database->server->port,
nslaves);
monitor_set_pending_status(database, SERVER_MASTER);
if (rval == NULL || rval->server->node_id > database->server->node_id)
rval = database;
}
}
database = database->next;
}
database = mon->databases;
/** Set master server IDs */
while (database)
{
ptr = mon->databases;
while (ptr)
{
for (i = 0; ptr->server->slaves[i]; i++)
{
if (ptr->server->slaves[i] == database->server->node_id)
{
database->server->master_id = ptr->server->node_id;
break;
}
}
ptr = ptr->next;
}
if (database->server->master_id <= 0 && SERVER_IS_SLAVE(database->server))
{
monitor_set_pending_status(database, SERVER_SLAVE_OF_EXTERNAL_MASTER);
}
database = database->next;
}
return rval;
}
/**
* Monitor an individual server
*
* @param handle The MySQL Monitor object
* @param database The database to probe
*/
static void
monitorDatabase(MONITOR *mon, MONITOR_SERVERS *database)
{
MYSQL_MONITOR* handle = mon->handle;
MYSQL_ROW row;
MYSQL_RES *result;
int isslave = 0;
char *uname = mon->user;
unsigned long int server_version = 0;
char *server_string;
if (database->server->monuser != NULL)
{
uname = database->server->monuser;
}
if (uname == NULL)
return;
/* Don't probe servers in maintenance mode */
if (SERVER_IN_MAINT(database->server))
return;
/** Store previous status */
database->mon_prev_status = database->server->status;
if (database->con == NULL || mysql_ping(database->con) != 0)
{
connect_result_t rval;
if ((rval = mon_connect_to_db(mon, database)) == MONITOR_CONN_OK)
{
server_clear_status(database->server, SERVER_AUTH_ERROR);
monitor_clear_pending_status(database, SERVER_AUTH_ERROR);
}
else
{
/* The current server is not running
*
* Store server NOT running in server and monitor server pending struct
*
*/
if (mysql_errno(database->con) == ER_ACCESS_DENIED_ERROR)
{
server_set_status(database->server, SERVER_AUTH_ERROR);
monitor_set_pending_status(database, SERVER_AUTH_ERROR);
}
server_clear_status(database->server, SERVER_RUNNING);
monitor_clear_pending_status(database, SERVER_RUNNING);
/* Also clear M/S state in both server and monitor server pending struct */
server_clear_status(database->server, SERVER_SLAVE);
server_clear_status(database->server, SERVER_MASTER);
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
/* Clean addition status too */
server_clear_status(database->server, SERVER_SLAVE_OF_EXTERNAL_MASTER);
server_clear_status(database->server, SERVER_STALE_STATUS);
monitor_clear_pending_status(database, SERVER_SLAVE_OF_EXTERNAL_MASTER);
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
/* Log connect failure only once */
if (mon_status_changed(database) && mon_print_fail_status(database))
{
mon_log_connect_error(database, rval);
}
return;
}
}
/* Store current status in both server and monitor server pending struct */
server_set_status(database->server, SERVER_RUNNING);
monitor_set_pending_status(database, SERVER_RUNNING);
/* get server version from current server */
server_version = mysql_get_server_version(database->con);
/* get server version string */
server_string = (char *) mysql_get_server_info(database->con);
if (server_string)
{
server_set_version_string(database->server, server_string);
}
/* get server_id form current node */
if (mysql_query(database->con, "SELECT @@server_id") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long server_id = -1;
if (mysql_field_count(database->con) != 1)
{
mysql_free_result(result);
MXS_ERROR("Unexpected result for 'SELECT @@server_id'. Expected 1 column."
" MySQL Version: %s", version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
server_id = strtol(row[0], NULL, 10);
if ((errno == ERANGE && (server_id == LONG_MAX
|| server_id == LONG_MIN)) || (errno != 0 && server_id == 0))
{
server_id = -1;
}
database->server->node_id = server_id;
}
mysql_free_result(result);
}
/* Check first for MariaDB 10.x.x and get status for multi-master replication */
if (server_version >= 100000)
{
monitor_mysql100_db(database);
}
else if (server_version >= 5 * 10000 + 5 * 100)
{
monitor_mysql55_db(database);
}
else
{
if (handle->mysql51_replication)
{
monitor_mysql51_db(database);
}
else if (report_version_err)
{
report_version_err = false;
MXS_ERROR("MySQL version is lower than 5.5 and 'mysql51_replication' option is "
"not enabled,"
" replication tree cannot be resolved. To enable MySQL 5.1 replication "
"detection, "
"add 'mysql51_replication=true' to the monitor section.");
}
}
}
/**
* The entry point for the monitoring module thread
*
* @param arg The handle of the monitor
*/
static void
monitorMain(void *arg)
{
MONITOR* mon = (MONITOR*) arg;
MYSQL_MONITOR *handle;
MONITOR_SERVERS *ptr;
int replication_heartbeat;
int detect_stale_master;
int num_servers = 0;
MONITOR_SERVERS *root_master = NULL;
size_t nrounds = 0;
int log_no_master = 1;
bool heartbeat_checked = false;
spinlock_acquire(&mon->lock);
handle = (MYSQL_MONITOR *) mon->handle;
spinlock_release(&mon->lock);
replication_heartbeat = handle->replicationHeartbeat;
detect_stale_master = handle->detectStaleMaster;
if (mysql_thread_init())
{
MXS_ERROR("mysql_thread_init failed in monitor module. Exiting.");
return;
}
handle->status = MONITOR_RUNNING;
while (1)
{
if (handle->shutdown)
{
handle->status = MONITOR_STOPPING;
mysql_thread_end();
handle->status = MONITOR_STOPPED;
return;
}
/** Wait base interval */
thread_millisleep(MON_BASE_INTERVAL_MS);
if (handle->replicationHeartbeat && !heartbeat_checked)
{
check_maxscale_schema_replication(mon);
heartbeat_checked = true;
}
/**
* Calculate how far away the monitor interval is from its full
* cycle and if monitor interval time further than the base
* interval, then skip monitoring checks. Excluding the first
* round.
*/
if (nrounds != 0 &&
((nrounds * MON_BASE_INTERVAL_MS) % mon->interval) >=
MON_BASE_INTERVAL_MS)
{
nrounds += 1;
continue;
}
nrounds += 1;
/* reset num_servers */
num_servers = 0;
/* start from the first server in the list */
ptr = mon->databases;
while (ptr)
{
ptr->mon_prev_status = ptr->server->status;
/* copy server status into monitor pending_status */
ptr->pending_status = ptr->server->status;
/* monitor current node */
monitorDatabase(mon, ptr);
/* reset the slave list of current node */
if (ptr->server->slaves)
{
free(ptr->server->slaves);
}
/* create a new slave list */
ptr->server->slaves = (long *) calloc(MONITOR_MAX_NUM_SLAVES, sizeof(long));
num_servers++;
if (mon_status_changed(ptr))
{
if (SRV_MASTER_STATUS(ptr->mon_prev_status))
{
/** Master failed, can't recover */
MXS_NOTICE("Server %s:%d lost the master status.",
ptr->server->name,
ptr->server->port);
}
/**
* Here we say: If the server's state changed
* so that it isn't running or some other way
* lost cluster membership, call call-back function
* of every DCB for which such callback was
* registered for this kind of issue (DCB_REASON_...)
*/
if (!(SERVER_IS_RUNNING(ptr->server)) ||
!(SERVER_IS_IN_CLUSTER(ptr->server)))
{
dcb_hangup_foreach(ptr->server);
}
}
if (mon_status_changed(ptr))
{
#if defined(SS_DEBUG)
MXS_INFO("Backend server %s:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#else
MXS_DEBUG("Backend server %s:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#endif
}
if (SERVER_IS_DOWN(ptr->server))
{
/** Increase this server'e error count */
ptr->mon_err_count += 1;
}
else
{
/** Reset this server's error count */
ptr->mon_err_count = 0;
}
ptr = ptr->next;
}
ptr = mon->databases;
/* if only one server is configured, that's is Master */
if (num_servers == 1)
{
if (SERVER_IS_RUNNING(ptr->server))
{
ptr->server->depth = 0;
/* status cleanup */
monitor_clear_pending_status(ptr, SERVER_SLAVE);
/* master status set */
monitor_set_pending_status(ptr, SERVER_MASTER);
ptr->server->depth = 0;
handle->master = ptr;
root_master = ptr;
}
}
else
{
/* Compute the replication tree */
if (handle->mysql51_replication)
root_master = build_mysql51_replication_tree(mon);
else
root_master = get_replication_tree(mon, num_servers);
}
/* Update server status from monitor pending status on that server*/
ptr = mon->databases;
while (ptr)
{
if (!SERVER_IN_MAINT(ptr->server))
{
/* If "detect_stale_master" option is On, let's use the previus master */
if (detect_stale_master &&
root_master &&
(!strcmp(ptr->server->name, root_master->server->name) &&
ptr->server->port == root_master->server->port) &&
(ptr->server->status & SERVER_MASTER) &&
!(ptr->pending_status & SERVER_MASTER))
{
/**
* In this case server->status will not be updated from pending_statu
* Set the STALE bit for this server in server struct
*/
server_set_status(ptr->server, SERVER_STALE_STATUS);
/* log it once */
if (mon_status_changed(ptr))
{
MXS_WARNING("[mysql_mon]: root server "
"[%s:%i] is no longer Master,"
" let's use it again even "
" if it could be a stale master,"
" you have been warned!",
ptr->server->name,
ptr->server->port);
}
}
else
{
ptr->server->status = ptr->pending_status;
}
}
ptr = ptr->next;
}
ptr = mon->databases;
monitor_event_t evtype;
while (ptr)
{
/** Execute monitor script if a server state has changed */
if (mon_status_changed(ptr))
{
evtype = mon_get_event_type(ptr);
if (isMySQLEvent(evtype))
{
MXS_NOTICE("Server changed state: %s[%s:%u]: %s",
ptr->server->unique_name,
ptr->server->name, ptr->server->port,
mon_get_event_name(ptr));
if (handle->script && handle->events[evtype])
{
monitor_launch_script(mon, ptr, handle->script);
}
}
}
ptr = ptr->next;
}
/* log master detection failure of first master becomes available after failure */
if (root_master &&
mon_status_changed(root_master) &&
!(root_master->server->status & SERVER_STALE_STATUS))
{
if (root_master->pending_status & (SERVER_MASTER) && SERVER_IS_RUNNING(root_master->server))
{
if (!(root_master->mon_prev_status & SERVER_STALE_STATUS) &&
!(root_master->server->status & SERVER_MAINT))
{
MXS_NOTICE("A Master Server is now available: %s:%i",
root_master->server->name,
root_master->server->port);
}
}
else
{
MXS_ERROR("No Master can be determined. Last known was %s:%i",
root_master->server->name,
root_master->server->port);
}
log_no_master = 1;
}
else
{
if (!root_master && log_no_master)
{
MXS_ERROR("No Master can be determined");
log_no_master = 0;
}
}
/* Do now the heartbeat replication set/get for MySQL Replication Consistency */
if (replication_heartbeat &&
root_master &&
(SERVER_IS_MASTER(root_master->server) ||
SERVER_IS_RELAY_SERVER(root_master->server)))
{
set_master_heartbeat(handle, root_master);
ptr = mon->databases;
while (ptr)
{
if ((!SERVER_IN_MAINT(ptr->server)) && SERVER_IS_RUNNING(ptr->server))
{
if (ptr->server->node_id != root_master->server->node_id &&
(SERVER_IS_SLAVE(ptr->server) ||
SERVER_IS_RELAY_SERVER(ptr->server)))
{
set_slave_heartbeat(mon, ptr);
}
}
ptr = ptr->next;
}
}
} /*< while (1) */
}
/**
* Set the default id to use in the monitor.
*
* @param arg The handle allocated by startMonitor
* @param id The id to set in monitor struct
*/
static void
defaultId(void *arg, unsigned long id)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *) arg;
memcpy(&handle->id, &id, sizeof(unsigned long));
}
/**
* Enable/Disable the MySQL Replication hearbeat, detecting slave lag behind master.
*
* @param arg The handle allocated by startMonitor
* @param enable To enable it 1, disable it with 0
*/
static void
replicationHeartbeat(void *arg, int enable)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *) arg;
memcpy(&handle->replicationHeartbeat, &enable, sizeof(int));
}
/**
* Enable/Disable the MySQL Replication Stale Master dectection, allowing a previouvsly detected master to still act as a Master.
* This option must be enabled in order to keep the Master when the replication is stopped or removed from slaves.
* If the replication is still stopped when MaxSclale is restarted no Master will be available.
*
* @param arg The handle allocated by startMonitor
* @param enable To enable it 1, disable it with 0
*/
static void
detectStaleMaster(void *arg, int enable)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *) arg;
memcpy(&handle->detectStaleMaster, &enable, sizeof(int));
}
/**
* Fetch a MySQL node by node_id
*
* @param ptr The list of servers to monitor
* @param node_id The MySQL server_id to fetch
* @return The server with the required server_id
*/
static MONITOR_SERVERS *
getServerByNodeId(MONITOR_SERVERS *ptr, long node_id)
{
SERVER *current;
while (ptr)
{
current = ptr->server;
if (current->node_id == node_id)
{
return ptr;
}
ptr = ptr->next;
}
return NULL;
}
/**
* Fetch a MySQL slave node from a node_id
*
* @param ptr The list of servers to monitor
* @param node_id The MySQL server_id to fetch
* @return The slave server of this node_id
*/
static MONITOR_SERVERS *
getSlaveOfNodeId(MONITOR_SERVERS *ptr, long node_id)
{
SERVER *current;
while (ptr)
{
current = ptr->server;
if (current->master_id == node_id)
{
return ptr;
}
ptr = ptr->next;
}
return NULL;
}
/*******
* This function sets the replication heartbeat
* into the maxscale_schema.replication_heartbeat table in the current master.
* The inserted values will be seen from all slaves replication from this master.
*
* @param handle The monitor handle
* @param database The number database server
*/
static void set_master_heartbeat(MYSQL_MONITOR *handle, MONITOR_SERVERS *database)
{
unsigned long id = handle->id;
time_t heartbeat;
time_t purge_time;
char heartbeat_insert_query[512] = "";
char heartbeat_purge_query[512] = "";
if (handle->master == NULL)
{
MXS_ERROR("[mysql_mon]: set_master_heartbeat called without an available Master server");
return;
}
/* create the maxscale_schema database */
if (mysql_query(database->con, "CREATE DATABASE IF NOT EXISTS maxscale_schema"))
{
MXS_ERROR("[mysql_mon]: Error creating maxscale_schema database in Master server"
": %s", mysql_error(database->con));
database->server->rlag = -1;
}
/* create repl_heartbeat table in maxscale_schema database */
if (mysql_query(database->con, "CREATE TABLE IF NOT EXISTS "
"maxscale_schema.replication_heartbeat "
"(maxscale_id INT NOT NULL, "
"master_server_id INT NOT NULL, "
"master_timestamp INT UNSIGNED NOT NULL, "
"PRIMARY KEY ( master_server_id, maxscale_id ) ) "
"ENGINE=MYISAM DEFAULT CHARSET=latin1"))
{
MXS_ERROR("[mysql_mon]: Error creating maxscale_schema.replication_heartbeat "
"table in Master server: %s", mysql_error(database->con));
database->server->rlag = -1;
}
/* auto purge old values after 48 hours*/
purge_time = time(0) - (3600 * 48);
sprintf(heartbeat_purge_query, "DELETE FROM maxscale_schema.replication_heartbeat WHERE master_timestamp < %lu", purge_time);
if (mysql_query(database->con, heartbeat_purge_query))
{
MXS_ERROR("[mysql_mon]: Error deleting from maxscale_schema.replication_heartbeat "
"table: [%s], %s",
heartbeat_purge_query,
mysql_error(database->con));
}
heartbeat = time(0);
/* set node_ts for master as time(0) */
database->server->node_ts = heartbeat;
sprintf(heartbeat_insert_query, "UPDATE maxscale_schema.replication_heartbeat SET master_timestamp = %lu WHERE master_server_id = %li AND maxscale_id = %lu", heartbeat, handle->master->server->node_id, id);
/* Try to insert MaxScale timestamp into master */
if (mysql_query(database->con, heartbeat_insert_query))
{
database->server->rlag = -1;
MXS_ERROR("[mysql_mon]: Error updating maxscale_schema.replication_heartbeat table: [%s], %s",
heartbeat_insert_query,
mysql_error(database->con));
}
else
{
if (mysql_affected_rows(database->con) == 0)
{
heartbeat = time(0);
sprintf(heartbeat_insert_query, "REPLACE INTO maxscale_schema.replication_heartbeat (master_server_id, maxscale_id, master_timestamp ) VALUES ( %li, %lu, %lu)", handle->master->server->node_id, id, heartbeat);
if (mysql_query(database->con, heartbeat_insert_query))
{
database->server->rlag = -1;
MXS_ERROR("[mysql_mon]: Error inserting into "
"maxscale_schema.replication_heartbeat table: [%s], %s",
heartbeat_insert_query,
mysql_error(database->con));
}
else
{
/* Set replication lag to 0 for the master */
database->server->rlag = 0;
MXS_DEBUG("[mysql_mon]: heartbeat table inserted data for %s:%i",
database->server->name, database->server->port);
}
}
else
{
/* Set replication lag as 0 for the master */
database->server->rlag = 0;
MXS_DEBUG("[mysql_mon]: heartbeat table updated for Master %s:%i",
database->server->name, database->server->port);
}
}
}
/*******
* This function gets the replication heartbeat
* from the maxscale_schema.replication_heartbeat table in the current slave
* and stores the timestamp and replication lag in the slave server struct
*
* @param handle The monitor handle
* @param database The number database server
*/
static void set_slave_heartbeat(MONITOR* mon, MONITOR_SERVERS *database)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR*) mon->handle;
unsigned long id = handle->id;
time_t heartbeat;
char select_heartbeat_query[256] = "";
MYSQL_ROW row;
MYSQL_RES *result;
if (handle->master == NULL)
{
MXS_ERROR("[mysql_mon]: set_slave_heartbeat called without an available Master server");
return;
}
/* Get the master_timestamp value from maxscale_schema.replication_heartbeat table */
sprintf(select_heartbeat_query, "SELECT master_timestamp "
"FROM maxscale_schema.replication_heartbeat "
"WHERE maxscale_id = %lu AND master_server_id = %li",
id, handle->master->server->node_id);
/* if there is a master then send the query to the slave with master_id */
if (handle->master != NULL && (mysql_query(database->con, select_heartbeat_query) == 0
&& (result = mysql_store_result(database->con)) != NULL))
{
int rows_found = 0;
while ((row = mysql_fetch_row(result)))
{
int rlag = -1;
time_t slave_read;
rows_found = 1;
heartbeat = time(0);
slave_read = strtoul(row[0], NULL, 10);
if ((errno == ERANGE && (slave_read == LONG_MAX || slave_read == LONG_MIN)) || (errno != 0 && slave_read == 0))
{
slave_read = 0;
}
if (slave_read)
{
/* set the replication lag */
rlag = heartbeat - slave_read;
}
/* set this node_ts as master_timestamp read from replication_heartbeat table */
database->server->node_ts = slave_read;
if (rlag >= 0)
{
/* store rlag only if greater than monitor sampling interval */
database->server->rlag = (rlag > (mon->interval / 1000)) ? rlag : 0;
}
else
{
database->server->rlag = -1;
}
MXS_DEBUG("Slave %s:%i has %i seconds lag",
database->server->name,
database->server->port,
database->server->rlag);
}
if (!rows_found)
{
database->server->rlag = -1;
database->server->node_ts = 0;
}
mysql_free_result(result);
}
else
{
database->server->rlag = -1;
database->server->node_ts = 0;
if (handle->master->server->node_id < 0)
{
MXS_ERROR("[mysql_mon]: error: replication heartbeat: "
"master_server_id NOT available for %s:%i",
database->server->name,
database->server->port);
}
else
{
MXS_ERROR("[mysql_mon]: error: replication heartbeat: "
"failed selecting from hearthbeat table of %s:%i : [%s], %s",
database->server->name,
database->server->port,
select_heartbeat_query,
mysql_error(database->con));
}
}
}
/*******
* This function computes the replication tree
* from a set of MySQL Master/Slave monitored servers
* and returns the root server with SERVER_MASTER bit.
* The tree is computed even for servers in 'maintenance' mode.
*
* @param handle The monitor handle
* @param num_servers The number of servers monitored
* @return The server at root level with SERVER_MASTER bit
*/
static MONITOR_SERVERS *get_replication_tree(MONITOR *mon, int num_servers)
{
MYSQL_MONITOR* handle = (MYSQL_MONITOR*) mon->handle;
MONITOR_SERVERS *ptr;
MONITOR_SERVERS *backend;
SERVER *current;
int depth = 0;
long node_id;
int root_level;
ptr = mon->databases;
root_level = num_servers;
while (ptr)
{
/* The server could be in SERVER_IN_MAINT
* that means SERVER_IS_RUNNING returns 0
* Let's check only for SERVER_IS_DOWN: server is not running
*/
if (SERVER_IS_DOWN(ptr->server))
{
ptr = ptr->next;
continue;
}
depth = 0;
current = ptr->server;
node_id = current->master_id;
if (node_id < 1)
{
MONITOR_SERVERS *find_slave;
find_slave = getSlaveOfNodeId(mon->databases, current->node_id);
if (find_slave == NULL)
{
current->depth = -1;
ptr = ptr->next;
continue;
}
else
{
current->depth = 0;
}
}
else
{
depth++;
}
while (depth <= num_servers)
{
/* set the root master at lowest depth level */
if (current->depth > -1 && current->depth < root_level)
{
root_level = current->depth;
handle->master = ptr;
}
backend = getServerByNodeId(mon->databases, node_id);
if (backend)
{
node_id = backend->server->master_id;
}
else
{
node_id = -1;
}
if (node_id > 0)
{
current->depth = depth + 1;
depth++;
}
else
{
MONITOR_SERVERS *master;
current->depth = depth;
master = getServerByNodeId(mon->databases, current->master_id);
if (master && master->server && master->server->node_id > 0)
{
add_slave_to_master(master->server->slaves, MONITOR_MAX_NUM_SLAVES, current->node_id);
master->server->depth = current->depth - 1;
monitor_set_pending_status(master, SERVER_MASTER);
handle->master = master;
}
else
{
if (current->master_id > 0)
{
/* this server is slave of another server not in MaxScale configuration
* we cannot use it as a real slave.
*/
monitor_clear_pending_status(ptr, SERVER_SLAVE);
monitor_set_pending_status(ptr, SERVER_SLAVE_OF_EXTERNAL_MASTER);
}
}
break;
}
}
ptr = ptr->next;
}
/*
* Return the root master
*/
if (handle->master != NULL)
{
/* If the root master is in MAINT, return NULL */
if (SERVER_IN_MAINT(handle->master->server))
{
return NULL;
}
else
{
return handle->master;
}
}
else
{
return NULL;
}
}
/*******
* This function add a slave id into the slaves server field
* of its master server
*
* @param slaves_list The slave list array of the master server
* @param list_size The size of the slave list
* @param node_id The node_id of the slave to be inserted
* @return 1 for inserted value and 0 otherwise
*/
static int add_slave_to_master(long *slaves_list, int list_size, long node_id)
{
for (int i = 0; i < list_size; i++)
{
if (slaves_list[i] == 0)
{
memcpy(&slaves_list[i], &node_id, sizeof(long));
return 1;
}
}
return 0;
}
static monitor_event_t mysql_events[] =
{
MASTER_DOWN_EVENT,
MASTER_UP_EVENT,
SLAVE_DOWN_EVENT,
SLAVE_UP_EVENT,
SERVER_DOWN_EVENT,
SERVER_UP_EVENT,
LOST_MASTER_EVENT,
LOST_SLAVE_EVENT,
NEW_MASTER_EVENT,
NEW_SLAVE_EVENT,
MAX_MONITOR_EVENT
};
/**
* Check if the MySQL monitor is monitoring this event type.
* @param event Event to check
* @return True if the event is monitored, false if it is not
* */
bool isMySQLEvent(monitor_event_t event)
{
int i;
for (i = 0; mysql_events[i] != MAX_MONITOR_EVENT; i++)
{
if (event == mysql_events[i])
return true;
}
return false;
}
/**
* Check if replicate_ignore_table is defined and if maxscale_schema.replication_hearbeat
* table is in the list.
* @param database Server to check
* @return False if the table is not replicated or an error occurred when querying
* the server
*/
bool check_replicate_ignore_table(MONITOR_SERVERS* database)
{
MYSQL_RES *result;
bool rval = true;
if (mysql_query(database->con,
"show variables like 'replicate_ignore_table'") == 0 &&
(result = mysql_store_result(database->con)) &&
mysql_num_fields(result) > 1)
{
MYSQL_ROW row;
while ((row = mysql_fetch_row(result)))
{
if (strlen(row[1]) > 0 &&
strcasestr(row[1], hb_table_name))
{
MXS_WARNING("'replicate_ignore_table' is "
"defined on server '%s' and '%s' was found in it. ",
database->server->unique_name, hb_table_name);
rval = false;
}
}
mysql_free_result(result);
}
else
{
MXS_ERROR("Failed to query server %s for "
"'replicate_ignore_table': %s",
database->server->unique_name,
mysql_error(database->con));
rval = false;
}
return rval;
}
/**
* Check if replicate_do_table is defined and if maxscale_schema.replication_hearbeat
* table is not in the list.
* @param database Server to check
* @return False if the table is not replicated or an error occurred when querying
* the server
*/
bool check_replicate_do_table(MONITOR_SERVERS* database)
{
MYSQL_RES *result;
bool rval = true;
if (mysql_query(database->con,
"show variables like 'replicate_do_table'") == 0 &&
(result = mysql_store_result(database->con)) &&
mysql_num_fields(result) > 1)
{
MYSQL_ROW row;
while ((row = mysql_fetch_row(result)))
{
if (strlen(row[1]) > 0 &&
strcasestr(row[1], hb_table_name) == NULL)
{
MXS_WARNING("'replicate_do_table' is "
"defined on server '%s' and '%s' was not found in it. ",
database->server->unique_name, hb_table_name);
rval = false;
}
}
mysql_free_result(result);
}
else
{
MXS_ERROR("Failed to query server %s for "
"'replicate_do_table': %s",
database->server->unique_name,
mysql_error(database->con));
rval = false;
}
return rval;
}
/**
* Check if replicate_wild_do_table is defined and if it doesn't match
* maxscale_schema.replication_heartbeat.
* @param database Database server
* @return False if the table is not replicated or an error occurred when trying to
* query the server.
*/
bool check_replicate_wild_do_table(MONITOR_SERVERS* database)
{
MYSQL_RES *result;
bool rval = true;
if (mysql_query(database->con,
"show variables like 'replicate_wild_do_table'") == 0 &&
(result = mysql_store_result(database->con)) &&
mysql_num_fields(result) > 1)
{
MYSQL_ROW row;
while ((row = mysql_fetch_row(result)))
{
if (strlen(row[1]) > 0)
{
mxs_pcre2_result_t rc = modutil_mysql_wildcard_match(row[1], hb_table_name);
if (rc == MXS_PCRE2_NOMATCH)
{
MXS_WARNING("'replicate_wild_do_table' is "
"defined on server '%s' and '%s' does not match it. ",
database->server->unique_name,
hb_table_name);
rval = false;
}
}
}
mysql_free_result(result);
}
else
{
MXS_ERROR("Failed to query server %s for "
"'replicate_wild_do_table': %s",
database->server->unique_name,
mysql_error(database->con));
rval = false;
}
return rval;
}
/**
* Check if replicate_wild_ignore_table is defined and if it matches
* maxscale_schema.replication_heartbeat.
* @param database Database server
* @return False if the table is not replicated or an error occurred when trying to
* query the server.
*/
bool check_replicate_wild_ignore_table(MONITOR_SERVERS* database)
{
MYSQL_RES *result;
bool rval = true;
if (mysql_query(database->con,
"show variables like 'replicate_wild_ignore_table'") == 0 &&
(result = mysql_store_result(database->con)) &&
mysql_num_fields(result) > 1)
{
MYSQL_ROW row;
while ((row = mysql_fetch_row(result)))
{
if (strlen(row[1]) > 0)
{
mxs_pcre2_result_t rc = modutil_mysql_wildcard_match(row[1], hb_table_name);
if (rc == MXS_PCRE2_MATCH)
{
MXS_WARNING("'replicate_wild_ignore_table' is "
"defined on server '%s' and '%s' matches it. ",
database->server->unique_name,
hb_table_name);
rval = false;
}
}
}
mysql_free_result(result);
}
else
{
MXS_ERROR("Failed to query server %s for "
"'replicate_wild_do_table': %s",
database->server->unique_name,
mysql_error(database->con));
rval = false;
}
return rval;
}
/**
* Check if the maxscale_schema.replication_heartbeat table is replicated on all
* servers and log a warning if problems were found.
* @param monitor Monitor structure
*/
void check_maxscale_schema_replication(MONITOR *monitor)
{
MONITOR_SERVERS* database = monitor->databases;
bool err = false;
while (database)
{
connect_result_t rval = mon_connect_to_db(monitor, database);
if (rval == MONITOR_CONN_OK)
{
if (!check_replicate_ignore_table(database) ||
!check_replicate_do_table(database) ||
!check_replicate_wild_do_table(database) ||
!check_replicate_wild_ignore_table(database))
{
err = true;
}
}
else
{
mon_log_connect_error(database, rval);
}
database = database->next;
}
if (err)
{
MXS_WARNING("Problems were encountered when "
"checking if '%s' is replicated. Make sure that the table is "
"replicated to all slaves.", hb_table_name);
}
}
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