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MXS-839: Store additional server information in mysqlmon

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Mysqlmon now stores the values of read_only, slave_sql_running,
slave_io_running, the name and position of the masters binlog and the
replication configuration status of the slave.

This allows more detailed server information to be displayed with the
`show monitor <name>` diagnostic interface. In addition to this, the new
structure used to store them provides an easy way to store information
that is specific to a monitor and the servers it monitors.

These new status variables can be used to implement better multi-master
detection in mysqlmon by using the value of read_only to resolve
situations where multiple master candidates are available.
This commit is contained in:
Markus Makela 2016-09-02 13:07:44 +03:00
parent cbf3ae0f8f
commit d745781bd0
2 changed files with 300 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
server/modules/monitor/mysqlmon.h
View File

@ -28,6 +28,7 @@
#include <modinfo.h>
#include <maxconfig.h>
#include <externcmd.h>
#include <hashtable.h>
/**
* @file mysqlmon.h - The MySQL monitor
@ -69,6 +70,7 @@ typedef struct
MONITOR_SERVERS *master; /**< Master server for MySQL Master/Slave replication */
char* script; /*< Script to call when state changes occur on servers */
bool events[MAX_MONITOR_EVENT]; /*< enabled events */
HASHTABLE *server_info; /**< Contains server specific information */
} MYSQL_MONITOR;
#endif

372
server/modules/monitor/mysqlmon/mysql_mon.c
View File

@ -50,6 +50,26 @@
#include <modutil.h>
#include <maxscale/alloc.h>
/** Column positions for SHOW SLAVE STATUS */
#define MYSQL55_STATUS_BINLOG_POS 5
#define MYSQL55_STATUS_BINLOG_NAME 6
#define MYSQL55_STATUS_IO_RUNNING 10
#define MYSQL55_STATUS_SQL_RUNNING 11
#define MYSQL55_STATUS_MASTER_ID 39
/** Column positions for SHOW SLAVE STATUS */
#define MARIA10_STATUS_BINLOG_NAME 7
#define MARIA10_STATUS_BINLOG_POS 8
#define MARIA10_STATUS_IO_RUNNING 12
#define MARIA10_STATUS_SQL_RUNNING 13
#define MARIA10_STATUS_MASTER_ID 41
/** Column positions for SHOW SLAVE HOSTS */
#define SLAVE_HOSTS_SERVER_ID 0
#define SLAVE_HOSTS_HOSTNAME 1
#define SLAVE_HOSTS_PORT 2
extern char *strcasestr(const char *haystack, const char *needle);
static void monitorMain(void *);
@ -128,6 +148,87 @@ GetModuleObject()
{
return &MyObject;
}
/**
* Monitor specific information about a server
*/
typedef struct mysql_server_info
{
int server_id; /**< Value of @@server_id */
int master_id; /**< Master server id from SHOW SLAVE STATUS*/
bool read_only; /**< Value of @@read_only */
bool slave_configured; /**< Whether SHOW SLAVE STATUS returned rows */
bool slave_io; /**< If Slave IO thread is running */
bool slave_sql; /**< If Slave SQL thread is running */
uint64_t binlog_pos; /**< Binlog position from SHOW SLAVE STATUS */
char *binlog_name; /**< Binlog name from SHOW SLAVE STATUS */
} MYSQL_SERVER_INFO;
/** Other values are implicitly zero initialized */
#define MYSQL_SERVER_INFO_INIT {.binlog_name = ""}
void* info_copy_func(const void *val)
{
ss_dassert(val);
MYSQL_SERVER_INFO *old_val = (MYSQL_SERVER_INFO*)val;
MYSQL_SERVER_INFO *new_val = MXS_MALLOC(sizeof(MYSQL_SERVER_INFO));
char *binlog_name = MXS_STRDUP(old_val->binlog_name);
if (new_val && binlog_name)
{
*new_val = *old_val;
new_val->binlog_name = binlog_name;
}
else
{
MXS_FREE(new_val);
MXS_FREE(binlog_name);
new_val = NULL;
}
return new_val;
}
void info_free_func(void *val)
{
if (val)
{
MYSQL_SERVER_INFO *old_val = (MYSQL_SERVER_INFO*)val;
MXS_FREE(old_val->binlog_name);
MXS_FREE(old_val);
}
}
/**
* @brief Helper function that initializes the server info hashtable
*
* @param handle MySQL monitor handle
* @param database List of monitored databases
* @return True on success, false if initialization failed. At the moment
* initialization can only fail if memory allocation fails.
*/
bool init_server_info(MYSQL_MONITOR *handle, MONITOR_SERVERS *database)
{
MYSQL_SERVER_INFO info = MYSQL_SERVER_INFO_INIT;
bool rval = true;
while (database)
{
/** Delete any existing structures and replace them with empty ones */
hashtable_delete(handle->server_info, database->server);
if (!hashtable_add(handle->server_info, database->server->unique_name, &info))
{
rval = false;
break;
}
database = database->next;
}
return rval;
}
/*lint +e14 */
/**
@ -143,7 +244,7 @@ static void *
startMonitor(MONITOR *monitor, const CONFIG_PARAMETER* params)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR*) monitor->handle;
bool have_events = false, script_error = false;
bool have_events = false, script_error = false, error = false;
if (handle)
{
@ -151,10 +252,19 @@ startMonitor(MONITOR *monitor, const CONFIG_PARAMETER* params)
}
else
{
if ((handle = (MYSQL_MONITOR *) MXS_MALLOC(sizeof(MYSQL_MONITOR))) == NULL)
handle = (MYSQL_MONITOR *) MXS_MALLOC(sizeof(MYSQL_MONITOR));
HASHTABLE *server_info = hashtable_alloc(MAX_NUM_SLAVES, hashtable_item_strhash, hashtable_item_strcmp);
if (handle == NULL || server_info == NULL)
{
MXS_FREE(handle);
hashtable_free(server_info);
return NULL;
}
hashtable_memory_fns(server_info, hashtable_item_strdup, info_copy_func,
hashtable_item_free, info_free_func);
handle->server_info = server_info;
handle->shutdown = 0;
handle->id = config_get_gateway_id();
handle->replicationHeartbeat = 0;
@ -214,25 +324,32 @@ startMonitor(MONITOR *monitor, const CONFIG_PARAMETER* params)
if (!check_monitor_permissions(monitor, "SHOW SLAVE STATUS"))
{
MXS_ERROR("Failed to start monitor. See earlier errors for more information.");
MXS_FREE(handle->script);
MXS_FREE(handle);
return NULL;
error = true;
}
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);
MXS_FREE(handle->script);
handle->script = NULL;
MXS_ERROR("[%s] Errors were found in the script configuration parameters ", monitor->name);
error = true;
}
/** If no specific events are given, enable them all */
if (!have_events)
else if (!have_events)
{
/** If no specific events are given, enable them all */
memset(handle->events, true, sizeof(handle->events));
}
if (thread_start(&handle->thread, monitorMain, monitor) == NULL)
if (!init_server_info(handle, monitor->databases))
{
error = true;
}
if (error)
{
hashtable_free(handle->server_info);
MXS_FREE(handle->script);
MXS_FREE(handle);
}
else if (thread_start(&handle->thread, monitorMain, monitor) == NULL)
{
MXS_ERROR("Failed to start monitor thread for monitor '%s'.", monitor->name);
}
@ -286,20 +403,28 @@ static void diagnostics(DCB *dcb, const MONITOR *mon)
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: ");
dcb_printf(dcb, "\nMonitored servers\n\n");
db = mon->databases;
sep = "";
while (db)
{
dcb_printf(dcb, "%s%s:%d", sep, db->server->name, db->server->port);
sep = ", ";
MYSQL_SERVER_INFO *serv_info = hashtable_fetch(handle->server_info, db->server->unique_name);
dcb_printf(dcb, "Server: %s\n", db->server->unique_name);
dcb_printf(dcb, "Server ID: %d\n", serv_info->server_id);
dcb_printf(dcb, "Read only: %s\n", serv_info->read_only ? "ON" : "OFF");
dcb_printf(dcb, "Slave configured: %s\n", serv_info->slave_configured ? "YES" : "NO");
dcb_printf(dcb, "Slave IO running: %s\n", serv_info->slave_io ? "YES" : "NO");
dcb_printf(dcb, "Slave SQL running: %s\n", serv_info->slave_sql ? "YES" : "NO");
dcb_printf(dcb, "Master ID: %d\n", serv_info->master_id);
dcb_printf(dcb, "Master binlog file: %s\n", serv_info->binlog_name);
dcb_printf(dcb, "Master binlog position: %lu\n", serv_info->binlog_pos);
dcb_printf(dcb, "\n");
db = db->next;
}
dcb_printf(dcb, "\n");
}
static inline void monitor_mysql100_db(MONITOR_SERVERS* database)
static inline void monitor_mysql100_db(MONITOR_SERVERS* database, MYSQL_SERVER_INFO *serv_info)
{
int isslave = 0;
MYSQL_RES* result;
@ -320,34 +445,69 @@ static inline void monitor_mysql100_db(MONITOR_SERVERS* database)
return;
}
while ((row = mysql_fetch_row(result)))
row = mysql_fetch_row(result);
if (row)
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[12], "Yes", 3) == 0
&& strncmp(row[13], "Yes", 3) == 0)
{
isslave += 1;
}
serv_info->slave_configured = true;
/* 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)
do
{
/* get Master_Server_Id values */
master_id = atol(row[41]);
if (master_id == 0)
/* get Slave_IO_Running and Slave_SQL_Running values*/
serv_info->slave_io = strncmp(row[MARIA10_STATUS_IO_RUNNING], "Yes", 3) == 0;
serv_info->slave_sql = strncmp(row[MARIA10_STATUS_SQL_RUNNING], "Yes", 3) == 0;
if (serv_info->slave_io && serv_info->slave_sql)
{
master_id = -1;
}
}
if (isslave == 0)
{
/** Only check binlog name for the first slave */
char *binlog_name = MXS_STRDUP(row[MARIA10_STATUS_BINLOG_NAME]);
i++;
if (binlog_name)
{
MXS_FREE(serv_info->binlog_name);
serv_info->binlog_name = binlog_name;
serv_info->binlog_pos = atol(row[MARIA10_STATUS_BINLOG_POS]);
}
}
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 (serv_info->slave_io)
{
/* get Master_Server_Id values */
master_id = atol(row[MARIA10_STATUS_MASTER_ID]);
if (master_id == 0)
{
master_id = -1;
}
}
i++;
row = mysql_fetch_row(result);
}
while (row);
}
else
{
/** SHOW ALL SLAVES STATUS returned no rows, replication not configured */
serv_info->slave_configured = false;
serv_info->slave_io = false;
serv_info->slave_sql = false;
serv_info->binlog_pos = 0;
serv_info->binlog_name[0] = '\0';
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
database->server->master_id = master_id;
serv_info->master_id = master_id;
mysql_free_result(result);
@ -385,7 +545,7 @@ static inline void monitor_mysql100_db(MONITOR_SERVERS* database)
}
}
static inline void monitor_mysql55_db(MONITOR_SERVERS* database)
static inline void monitor_mysql55_db(MONITOR_SERVERS* database, MYSQL_SERVER_INFO *serv_info)
{
bool isslave = false;
MYSQL_RES* result;
@ -404,32 +564,60 @@ static inline void monitor_mysql55_db(MONITOR_SERVERS* database)
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;
}
row = mysql_fetch_row(result);
/* 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)
if (row)
{
serv_info->slave_configured = true;
do
{
/* get Master_Server_Id values */
master_id = atol(row[39]);
if (master_id == 0)
/* get Slave_IO_Running and Slave_SQL_Running values*/
serv_info->slave_io = strncmp(row[MYSQL55_STATUS_IO_RUNNING], "Yes", 3) == 0;
serv_info->slave_sql = strncmp(row[MYSQL55_STATUS_SQL_RUNNING], "Yes", 3) == 0;
if (serv_info->slave_io && serv_info->slave_sql)
{
master_id = -1;
isslave = 1;
serv_info->binlog_pos = atol(row[MYSQL55_STATUS_BINLOG_POS]);
char *binlog_name = MXS_STRDUP(row[MYSQL55_STATUS_BINLOG_NAME]);
if (binlog_name)
{
MXS_FREE(serv_info->binlog_name);
serv_info->binlog_name = binlog_name;
}
}
/* 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 (serv_info->slave_io)
{
/* get Master_Server_Id values */
master_id = atol(row[MYSQL55_STATUS_MASTER_ID]);
if (master_id == 0)
{
master_id = -1;
}
}
row = mysql_fetch_row(result);
}
while (row);
}
else
{
/** SHOW SLAVE STATUS returned no rows, slave is not configured. */
serv_info->slave_configured = false;
serv_info->binlog_pos = 0;
serv_info->binlog_name[0] = '\0';
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
database->server->master_id = master_id;
serv_info->master_id = master_id;
mysql_free_result(result);
}
@ -457,7 +645,7 @@ static inline void monitor_mysql55_db(MONITOR_SERVERS* database)
}
}
static inline void monitor_mysql51_db(MONITOR_SERVERS* database)
static inline void monitor_mysql51_db(MONITOR_SERVERS* database, MYSQL_SERVER_INFO *serv_info)
{
bool isslave = false;
MYSQL_RES* result;
@ -476,16 +664,46 @@ static inline void monitor_mysql51_db(MONITOR_SERVERS* database)
return;
}
while ((row = mysql_fetch_row(result)))
row = mysql_fetch_row(result);
if (row)
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[10], "Yes", 3) == 0
&& strncmp(row[11], "Yes", 3) == 0)
serv_info->slave_configured = true;
do
{
isslave = 1;
/* get Slave_IO_Running and Slave_SQL_Running values*/
serv_info->slave_io = strncmp(row[MYSQL55_STATUS_IO_RUNNING], "Yes", 3) == 0;
serv_info->slave_sql = strncmp(row[MYSQL55_STATUS_SQL_RUNNING], "Yes", 3) == 0;
if (serv_info->slave_io && serv_info->slave_sql)
{
isslave = 1;
serv_info->binlog_pos = atol(row[MYSQL55_STATUS_BINLOG_POS]);
char *binlog_name = MXS_STRDUP(row[MYSQL55_STATUS_BINLOG_NAME]);
if (binlog_name)
{
MXS_FREE(serv_info->binlog_name);
serv_info->binlog_name = binlog_name;
}
}
row = mysql_fetch_row(result);
}
while (row);
}
else
{
/** SHOW SLAVE STATUS returned no rows, slave is not configured. */
serv_info->slave_configured = false;
serv_info->binlog_pos = 0;
serv_info->binlog_name[0] = '\0';
}
mysql_free_result(result);
serv_info->master_id = -1;
}
/* Remove addition info */
@ -550,9 +768,9 @@ static MONITOR_SERVERS *build_mysql51_replication_tree(MONITOR *mon)
while (nslaves < MAX_NUM_SLAVES && (row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
database->server->slaves[nslaves] = atol(row[0]);
database->server->slaves[nslaves] = atol(row[SLAVE_HOSTS_SERVER_ID]);
nslaves++;
MXS_DEBUG("Found slave at %s:%s", row[1], row[2]);
MXS_DEBUG("Found slave at %s:%s", row[SLAVE_HOSTS_HOSTNAME], row[SLAVE_HOSTS_PORT]);
}
database->server->slaves[nslaves] = 0;
}
@ -701,16 +919,19 @@ monitorDatabase(MONITOR *mon, MONITOR_SERVERS *database)
server_set_version_string(database->server, server_string);
}
/* get server_id form current node */
if (mysql_query(database->con, "SELECT @@server_id") == 0
MYSQL_SERVER_INFO *serv_info = hashtable_fetch(handle->server_info, database->server->unique_name);
ss_dassert(serv_info);
/* Get server_id and read_only from current node */
if (mysql_query(database->con, "SELECT @@server_id, @@read_only") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long server_id = -1;
if (mysql_field_count(database->con) != 1)
if (mysql_field_count(database->con) != 2)
{
mysql_free_result(result);
MXS_ERROR("Unexpected result for 'SELECT @@server_id'. Expected 1 column."
MXS_ERROR("Unexpected result for 'SELECT @@server_id, @@read_only'. Expected 2 columns."
" MySQL Version: %s", version_str);
return;
}
@ -723,7 +944,10 @@ monitorDatabase(MONITOR *mon, MONITOR_SERVERS *database)
{
server_id = -1;
}
database->server->node_id = server_id;
serv_info->server_id = server_id;
serv_info->read_only = (row[1] && strcmp(row[1], "1") == 0);
}
mysql_free_result(result);
}
@ -731,17 +955,17 @@ monitorDatabase(MONITOR *mon, MONITOR_SERVERS *database)
/* Check first for MariaDB 10.x.x and get status for multi-master replication */
if (server_version >= 100000)
{
monitor_mysql100_db(database);
monitor_mysql100_db(database, serv_info);
}
else if (server_version >= 5 * 10000 + 5 * 100)
{
monitor_mysql55_db(database);
monitor_mysql55_db(database, serv_info);
}
else
{
if (handle->mysql51_replication)
{
monitor_mysql51_db(database);
monitor_mysql51_db(database, serv_info);
}
else if (report_version_err)
{