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In dcb.c:dcb_close DCB is removed either before or after the call dcb->func.close. Since mysql backend protocol sends COM_QUIT and thus, writes to backend DCB, it is kept in DCB_STATE_POLLING until the write is completed.

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dcb.h: define ERRHAND temporarily since changes are still behind that macro
Defined two error handling actions in router.h: ERRACT_NEW_COMMECTION and ERRACT_REPLY_CLIENT.
Failed database is logged at expanding frequence to error and to message log due changes in mysql_mon.c. Added two new members in MONITOR_SERVERS: mon_err_count, and mon_prev_status so that each backend can be treated individually.

Error handling: if mysql_backend.c:dcb_read fails, router's handleError is called instead of closing session.
	If mysql_client.c:SESSION_ROUTE_QUERY fails router's handleError is called instead of sending error to client.

	readwritesplit.c:select_connect_backend_servers is modified so that in can be called during active router session. When called, it attempts to find one master and maximum number of configured slaves in correct state if necessary.
	When handleError needs to replace failed unit it now calls select_connect_backend_servers.
This commit is contained in:
VilhoRaatikka
2014-06-08 19:36:12 +03:00
parent 916b763685
commit 889bdd4f8c
8 changed files with 298 additions and 121 deletions
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87
server/modules/monitor/mysql_mon.c
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@ -73,6 +73,8 @@ static void diagnostics(DCB *, void *);
static void setInterval(void *, unsigned long);
static void defaultId(void *, unsigned long);
static void replicationHeartbeat(void *, int);
static bool mon_status_changed(MONITOR_SERVERS* mon_srv);
static bool mon_print_fail_status(MONITOR_SERVERS* mon_srv);
static MONITOR_OBJECT MyObject = { startMonitor, stopMonitor, registerServer, unregisterServer, defaultUser, diagnostics, setInterval, defaultId, replicationHeartbeat };
@ -180,7 +182,10 @@ MONITOR_SERVERS *ptr, *db;
db->server = server;
db->con = NULL;
db->next = NULL;
db->mon_err_count = 0;
db->mon_prev_status = 0;
spinlock_acquire(&handle->lock);
if (handle->databases == NULL)
handle->databases = db;
else
@ -310,15 +315,17 @@ monitorDatabase(MYSQL_MONITOR *handle, MONITOR_SERVERS *database)
MYSQL_ROW row;
MYSQL_RES *result;
int num_fields;
int ismaster = 0, isslave = 0;
char *uname = handle->defaultUser, *passwd = handle->defaultPasswd;
int ismaster = 0;
int isslave = 0;
char *uname = handle->defaultUser;
char *passwd = handle->defaultPasswd;
unsigned long int server_version = 0;
char *server_string;
unsigned long id = handle->id;
int replication_heartbeat = handle->replicationHeartbeat;
static int conn_err_count;
if (database->server->monuser != NULL)
if (database->server->monuser != NULL)
{
uname = database->server->monuser;
passwd = database->server->monpw;
@ -331,6 +338,9 @@ static int conn_err_count;
if (SERVER_IN_MAINT(database->server))
return;
/** Store prevous status */
database->mon_prev_status = database->server->status;
if (database->con == NULL || mysql_ping(database->con) != 0)
{
char *dpwd = decryptPassword(passwd);
@ -338,6 +348,7 @@ static int conn_err_count;
int read_timeout = 1;
database->con = mysql_init(NULL);
rc = mysql_options(database->con, MYSQL_OPT_READ_TIMEOUT, (void *)&read_timeout);
if (mysql_real_connect(database->con,
@ -349,7 +360,9 @@ static int conn_err_count;
NULL,
0) == NULL)
{
if (conn_err_count%10 == 0)
free(dpwd);
if (mon_print_fail_status(database))
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
@ -359,17 +372,15 @@ static int conn_err_count;
database->server->port,
mysql_error(database->con))));
}
conn_err_count += 1;
free(dpwd);
/** Store current status */
server_clear_status(database->server, SERVER_RUNNING);
return;
}
free(dpwd);
}
/* If we get this far then we have a working connection */
server_set_status(database->server, SERVER_RUNNING);
}
/** Store current status */
server_set_status(database->server, SERVER_RUNNING);
/* get server version from current server */
server_version = mysql_get_server_version(database->con);
@ -629,7 +640,7 @@ static int conn_err_count;
}
}
}
/** Store current status */
if (ismaster)
{
server_set_status(database->server, SERVER_MASTER);
@ -657,7 +668,6 @@ monitorMain(void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr;
static int err_count;
if (mysql_thread_init())
{
@ -680,13 +690,10 @@ static int err_count;
ptr = handle->databases;
while (ptr)
{
unsigned int prev_status = ptr->server->status;
monitorDatabase(handle, ptr);
if (ptr->server->status != prev_status ||
(SERVER_IS_DOWN(ptr->server) &&
err_count%10 == 0))
if (mon_status_changed(ptr) ||
mon_print_fail_status(ptr))
{
LOGIF(LM, (skygw_log_write_flush(
LOGFILE_MESSAGE,
@ -697,7 +704,13 @@ static int err_count;
}
if (SERVER_IS_DOWN(ptr->server))
{
err_count += 1;
/** 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;
}
@ -743,3 +756,39 @@ replicationHeartbeat(void *arg, int replicationHeartbeat)
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
memcpy(&handle->replicationHeartbeat, &replicationHeartbeat, sizeof(int));
}
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;
}
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%modval == 0)
{
succp = true;
}
else
{
succp = false;
}
return succp;
}