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MaxScale/server/modules/monitor/mysql_mon.c

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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.
*
* @endverbatim
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <monitor.h>
#include <mysqlmon.h>
#include <thread.h>
#include <mysql.h>
#include <mysqld_error.h>
#include <skygw_utils.h>
#include <log_manager.h>
#include <secrets.h>
#include <dcb.h>
#include <modinfo.h>
/** Defined in log_manager.cc */
extern int lm_enabled_logfiles_bitmask;
extern size_t log_ses_count[];
extern __thread log_info_t tls_log_info;
static void monitorMain(void *);
static char *version_str = "V1.4.0";
MODULE_INFO info = {
MODULE_API_MONITOR,
MODULE_BETA_RELEASE,
MONITOR_VERSION,
"A MySQL Master/Slave replication monitor"
};
static void *startMonitor(void *);
static void stopMonitor(void *);
static void registerServer(void *, SERVER *);
static void unregisterServer(void *, SERVER *);
static void defaultUser(void *, char *, char *);
static void diagnostics(DCB *, void *);
static void setInterval(void *, size_t);
static void defaultId(void *, unsigned long);
static void replicationHeartbeat(void *, int);
static void detectStaleMaster(void *, int);
static void setNetworkTimeout(void *, int, int);
static bool mon_status_changed(MONITOR_SERVERS* mon_srv);
static bool mon_print_fail_status(MONITOR_SERVERS* mon_srv);
static MONITOR_SERVERS *getServerByNodeId(MONITOR_SERVERS *, long);
static MONITOR_SERVERS *getSlaveOfNodeId(MONITOR_SERVERS *, long);
static MONITOR_SERVERS *get_replication_tree(MYSQL_MONITOR *, int);
static void set_master_heartbeat(MYSQL_MONITOR *, MONITOR_SERVERS *);
static void set_slave_heartbeat(MYSQL_MONITOR *, MONITOR_SERVERS *);
static int add_slave_to_master(long *, int, long);
static void monitor_set_pending_status(MONITOR_SERVERS *, int);
static void monitor_clear_pending_status(MONITOR_SERVERS *, int);
static MONITOR_OBJECT MyObject = {
startMonitor,
stopMonitor,
registerServer,
unregisterServer,
defaultUser,
diagnostics,
setInterval,
setNetworkTimeout,
defaultId,
replicationHeartbeat,
detectStaleMaster,
NULL
};
/**
* 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()
{
LOGIF(LM, (skygw_log_write(
LOGFILE_MESSAGE,
"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
* @return A handle to use when interacting with the monitor
*/
static void *
startMonitor(void *arg)
{
MYSQL_MONITOR *handle;
if (arg)
{
handle = arg; /* Must be a restart */
handle->shutdown = 0;
}
else
{
if ((handle = (MYSQL_MONITOR *)malloc(sizeof(MYSQL_MONITOR))) == NULL)
return NULL;
handle->databases = NULL;
handle->shutdown = 0;
handle->defaultUser = NULL;
handle->defaultPasswd = NULL;
handle->id = MONITOR_DEFAULT_ID;
handle->interval = MONITOR_INTERVAL;
handle->replicationHeartbeat = 0;
handle->detectStaleMaster = 0;
handle->master = NULL;
handle->connect_timeout=DEFAULT_CONNECT_TIMEOUT;
handle->read_timeout=DEFAULT_READ_TIMEOUT;
handle->write_timeout=DEFAULT_WRITE_TIMEOUT;
spinlock_init(&handle->lock);
}
handle->tid = (THREAD)thread_start(monitorMain, handle);
return handle;
}
/**
* Stop a running monitor
*
* @param arg Handle on thr running monior
*/
static void
stopMonitor(void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
handle->shutdown = 1;
thread_wait((void *)handle->tid);
}
/**
* Register a server that must be added to the monitored servers for
* a monitoring module.
*
* @param arg A handle on the running monitor module
* @param server The server to add
*/
static void
registerServer(void *arg, SERVER *server)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr, *db;
if ((db = (MONITOR_SERVERS *)malloc(sizeof(MONITOR_SERVERS))) == NULL)
return;
db->server = server;
db->con = NULL;
db->next = NULL;
db->mon_err_count = 0;
db->mon_prev_status = 0;
/* pending status is updated by get_replication_tree */
db->pending_status = 0;
spinlock_acquire(&handle->lock);
if (handle->databases == NULL)
handle->databases = db;
else
{
ptr = handle->databases;
while (ptr->next != NULL)
ptr = ptr->next;
ptr->next = db;
}
spinlock_release(&handle->lock);
}
/**
* Remove a server from those being monitored by a monitoring module
*
* @param arg A handle on the running monitor module
* @param server The server to remove
*/
static void
unregisterServer(void *arg, SERVER *server)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr, *lptr;
spinlock_acquire(&handle->lock);
if (handle->databases == NULL)
{
spinlock_release(&handle->lock);
return;
}
if (handle->databases->server == server)
{
ptr = handle->databases;
handle->databases = handle->databases->next;
free(ptr);
}
else
{
ptr = handle->databases;
while (ptr->next != NULL && ptr->next->server != server)
ptr = ptr->next;
if (ptr->next)
{
lptr = ptr->next;
ptr->next = ptr->next->next;
free(lptr);
}
}
spinlock_release(&handle->lock);
}
/**
* Set the default username and password to use to monitor if the server does not
* override this.
*
* @param arg The handle allocated by startMonitor
* @param uname The default user name
* @param passwd The default password
*/
static void
defaultUser(void *arg, char *uname, char *passwd)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
if (handle->defaultUser)
free(handle->defaultUser);
if (handle->defaultPasswd)
free(handle->defaultPasswd);
handle->defaultUser = strdup(uname);
handle->defaultPasswd = strdup(passwd);
}
/**
* Daignostic interface
*
* @param dcb DCB to print diagnostics
* @param arg The monitor handle
*/
static void diagnostics(DCB *dcb, void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
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", handle->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", handle->connect_timeout);
dcb_printf(dcb,"\tRead Timeout:\t\t%i seconds\n", handle->read_timeout);
dcb_printf(dcb,"\tWrite Timeout:\t\t%i seconds\n", handle->write_timeout);
dcb_printf(dcb, "\tMonitored servers: ");
db = handle->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");
}
/**
* Monitor an individual server
*
* @param handle The MySQL Monitor object
* @param database The database to probe
*/
static void
monitorDatabase(MYSQL_MONITOR *handle, MONITOR_SERVERS *database)
{
MYSQL_ROW row;
MYSQL_RES *result;
int num_fields;
int isslave = 0;
char *uname = handle->defaultUser;
char *passwd = handle->defaultPasswd;
unsigned long int server_version = 0;
char *server_string;
if (database->server->monuser != NULL)
{
uname = database->server->monuser;
passwd = database->server->monpw;
}
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)
{
char *dpwd = decryptPassword(passwd);
int rc;
int connect_timeout = handle->connect_timeout;
int read_timeout = handle->read_timeout;
int write_timeout = handle->write_timeout;
database->con = mysql_init(NULL);
rc = mysql_options(database->con, MYSQL_OPT_CONNECT_TIMEOUT, (void *)&connect_timeout);
rc = mysql_options(database->con, MYSQL_OPT_READ_TIMEOUT, (void *)&read_timeout);
rc = mysql_options(database->con, MYSQL_OPT_WRITE_TIMEOUT, (void *)&write_timeout);
if (mysql_real_connect(database->con,
database->server->name,
uname,
dpwd,
NULL,
database->server->port,
NULL,
0) == NULL)
{
free(dpwd);
/* 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))
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Monitor was unable to connect to "
"server %s:%d : \"%s\"",
database->server->name,
database->server->port,
mysql_error(database->con))));
}
return;
}
else
{
server_clear_status(database->server, SERVER_AUTH_ERROR);
monitor_clear_pending_status(database, SERVER_AUTH_ERROR);
}
free(dpwd);
}
/* 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) {
database->server->server_string = realloc(database->server->server_string, strlen(server_string)+1);
if (database->server->server_string)
strcpy(database->server->server_string, 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;
num_fields = mysql_num_fields(result);
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 if the Slave_SQL_Running and Slave_IO_Running status is
* set to Yes
*/
/* Check first for MariaDB 10.x.x and get status for multimaster replication */
if (server_version >= 100000) {
if (mysql_query(database->con, "SHOW ALL SLAVES STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
int i = 0;
long master_id = -1;
num_fields = mysql_num_fields(result);
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;
}
} else {
if (mysql_query(database->con, "SHOW SLAVE STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long master_id = -1;
num_fields = mysql_num_fields(result);
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);
}
}
/**
* The entry point for the monitoring module thread
*
* @param arg The handle of the monitor
*/
static void
monitorMain(void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr;
int replication_heartbeat = handle->replicationHeartbeat;
int detect_stale_master = handle->detectStaleMaster;
int num_servers=0;
MONITOR_SERVERS *root_master = NULL;
size_t nrounds = 0;
int log_no_master = 1;
if (mysql_thread_init())
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Fatal : mysql_thread_init failed in monitor "
"module. Exiting.\n")));
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);
/**
* 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)%handle->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 = handle->databases;
while (ptr)
{
/* copy server status into monitor pending_status */
ptr->pending_status = ptr->server->status;
/* monitor current node */
monitorDatabase(handle, 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))
{
dcb_call_foreach(DCB_REASON_NOT_RESPONDING);
}
if (mon_status_changed(ptr))
{
#if defined(SS_DEBUG)
LOGIF(LT, (skygw_log_write_flush(
LOGFILE_TRACE,
"Backend server %s:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server))));
#else
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_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 = handle->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 */
root_master = get_replication_tree(handle, num_servers);
}
/* Update server status from monitor pending status on that server*/
ptr = handle->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)) {
LOGIF(LM, (skygw_log_write_flush(
LOGFILE_MESSAGE, "[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;
}
/* log master detection failure od 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)) {
if (!(root_master->mon_prev_status & SERVER_STALE_STATUS) && !(root_master->server->status & SERVER_MAINT)) {
LOGIF(LM, (skygw_log_write(
LOGFILE_MESSAGE,
"Info: A Master Server is now available: %s:%i",
root_master->server->name,
root_master->server->port)));
}
} else {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"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) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"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 = handle->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(handle, 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));
}
/**
* Set the monitor sampling interval.
*
* @param arg The handle allocated by startMonitor
* @param interval The interval to set in monitor struct, in milliseconds
*/
static void
setInterval(void *arg, size_t interval)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
memcpy(&handle->interval, &interval, 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));
}
/**
* Check if current monitored server status has changed
*
* @param mon_srv The monitored server
* @return true if status has changed or false
*/
static bool mon_status_changed(
MONITOR_SERVERS* mon_srv)
{
bool succp;
if (mon_srv->mon_prev_status != mon_srv->server->status)
{
succp = true;
}
else
{
succp = false;
}
return succp;
}
/**
* Check if current monitored server has a loggable failure status
*
* @param mon_srv The monitored server
* @return true if failed status can be logged or false
*/
static bool mon_print_fail_status(
MONITOR_SERVERS* mon_srv)
{
bool succp;
int errcount = mon_srv->mon_err_count;
uint8_t modval;
modval = 1<<(MIN(errcount/10, 7));
if (SERVER_IS_DOWN(mon_srv->server) && errcount == 0)
{
succp = true;
}
else
{
succp = false;
}
return succp;
}
/**
* 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) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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")) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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")) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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)) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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;
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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;
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_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;
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_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(MYSQL_MONITOR *handle, MONITOR_SERVERS *database) {
unsigned long id = handle->id;
time_t heartbeat;
char select_heartbeat_query[256] = "";
MYSQL_ROW row;
MYSQL_RES *result;
int num_fields;
if (handle->master == NULL) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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;
num_fields = mysql_num_fields(result);
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 > (handle->interval / 1000)) ? rlag : 0;
} else {
database->server->rlag = -1;
}
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_DEBUG,
"[mysql_mon]: replication heartbeat: "
"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) {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"[mysql_mon]: error: replication heartbeat: "
"master_server_id NOT available for %s:%i",
database->server->name,
database->server->port)));
} else {
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_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(MYSQL_MONITOR *handle, int num_servers) {
MONITOR_SERVERS *ptr;
MONITOR_SERVERS *backend;
SERVER *current;
int depth=0;
long node_id;
int root_level;
ptr = handle->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(handle->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(handle->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(handle->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) {
int i;
for (i = 0; i< list_size; i++) {
if (slaves_list[i] == 0) {
memcpy(&slaves_list[i], &node_id, sizeof(long));
return 1;
}
}
return 0;
}
/**
* Set a pending status bit in the monior server
*
* @param server The server to update
* @param bit The bit to clear for the server
*/
static void
monitor_set_pending_status(MONITOR_SERVERS *ptr, int bit)
{
ptr->pending_status |= bit;
}
/**
* Clear a pending status bit in the monior server
*
* @param server The server to update
* @param bit The bit to clear for the server
*/
static void
monitor_clear_pending_status(MONITOR_SERVERS *ptr, int bit)
{
ptr->pending_status &= ~bit;
}
/**
* Set the default id to use in the monitor.
*
* @param arg The handle allocated by startMonitor
* @param type The connect timeout type
* @param value The timeout value to set
*/
static void
setNetworkTimeout(void *arg, int type, int value)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
int max_timeout = (int)(handle->interval/1000);
int new_timeout = max_timeout -1;
if (new_timeout <= 0)
new_timeout = DEFAULT_CONNECT_TIMEOUT;
switch(type) {
case MONITOR_CONNECT_TIMEOUT:
if (value < max_timeout) {
memcpy(&handle->connect_timeout, &value, sizeof(int));
} else {
memcpy(&handle->connect_timeout, &new_timeout, sizeof(int));
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"warning : Monitor Connect Timeout %i is greater than monitor interval ~%i seconds"
", lowering to %i seconds", value, max_timeout, new_timeout)));
}
break;
case MONITOR_READ_TIMEOUT:
if (value < max_timeout) {
memcpy(&handle->read_timeout, &value, sizeof(int));
} else {
memcpy(&handle->read_timeout, &new_timeout, sizeof(int));
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"warning : Monitor Read Timeout %i is greater than monitor interval ~%i seconds"
", lowering to %i seconds", value, max_timeout, new_timeout)));
}
break;
case MONITOR_WRITE_TIMEOUT:
if (value < max_timeout) {
memcpy(&handle->write_timeout, &value, sizeof(int));
} else {
memcpy(&handle->write_timeout, &new_timeout, sizeof(int));
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"warning : Monitor Write Timeout %i is greater than monitor interval ~%i seconds"
", lowering to %i seconds", value, max_timeout, new_timeout)));
}
break;
default:
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Monitor setNetworkTimeout received an unsupported action type %i", type)));
break;
}
}
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