hcq/MaxScale
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

MXS-922: Move server weight calculation into the core

Browse Source 
The core now does the server weight calculation instead of each router
module doing the same thing.
This commit is contained in:
Markus Makela
2016-11-03 11:24:32 +02:00
parent bf62f8950a
commit a097204c70
4 changed files with 106 additions and 152 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
server/core/service.c
View File

@ -66,6 +66,9 @@
#include <maxscale/alloc.h>
#include <maxscale/utils.h>
/** Base value for server weights */
#define SERVICE_BASE_SERVER_WEIGHT 1000
/** To be used with configuration type checks */
typedef struct typelib_st
{
@ -96,6 +99,7 @@ static void service_add_qualified_param(SERVICE* svc,
CONFIG_PARAMETER* param);
static void service_internal_restart(void *data);
static void service_queue_check(void *data);
static void service_calculate_weights(SERVICE *service);
/**
* Allocate a new service for the gateway to support
@ -474,6 +478,9 @@ static void free_string_array(char** array)
int
serviceStart(SERVICE *service)
{
/** Calculate the server weights */
service_calculate_weights(service);
int listeners = 0;
char **router_options = copy_string_array(service->routerOptions);
@ -729,6 +736,26 @@ int serviceHasProtocol(SERVICE *service, const char *protocol,
return proto != NULL;
}
/**
* Allocate a new server reference
*
* @param server Server to refer to
* @return Server reference or NULL on error
*/
static SERVER_REF* server_ref_alloc(SERVER *server)
{
SERVER_REF *sref = MXS_MALLOC(sizeof(SERVER_REF));
if (sref)
{
sref->next = NULL;
sref->server = server;
sref->weight = SERVICE_BASE_SERVER_WEIGHT;
}
return sref;
}
/**
* Add a backend database server to a service
*
@ -738,13 +765,10 @@ int serviceHasProtocol(SERVICE *service, const char *protocol,
void
serviceAddBackend(SERVICE *service, SERVER *server)
{
SERVER_REF *sref = MXS_MALLOC(sizeof(SERVER_REF));
SERVER_REF *sref = server_ref_alloc(server);
if (sref)
{
sref->next = NULL;
sref->server = server;
spinlock_acquire(&service->spin);
if (service->dbref)
{
@ -2027,3 +2051,76 @@ bool service_all_services_have_listeners()
spinlock_release(&service_spin);
return rval;
}
static void service_calculate_weights(SERVICE *service)
{
char *weightby = serviceGetWeightingParameter(service);
if (weightby && service->dbref)
{
/** Service has a weighting parameter and at least one server */
int total = 0;
/** Calculate total weight */
for (SERVER_REF *server = service->dbref; server; server = server->next)
{
server->weight = SERVICE_BASE_SERVER_WEIGHT;
char *param = serverGetParameter(server->server, weightby);
if (param)
{
total += atoi(param);
}
}
if (total == 0)
{
MXS_WARNING("Weighting Parameter for service '%s' will be ignored as "
"no servers have values for the parameter '%s'.",
service->name, weightby);
}
else if (total < 0)
{
MXS_ERROR("Sum of weighting parameter '%s' for service '%s' exceeds "
"maximum value of %d. Weighting will be ignored.",
weightby, service->name, INT_MAX);
}
else
{
/** Calculate the relative weight of the servers */
for (SERVER_REF *server = service->dbref; server; server = server->next)
{
char *param = serverGetParameter(server->server, weightby);
if (param)
{
int wght = atoi(param);
int perc = (wght * SERVICE_BASE_SERVER_WEIGHT) / total;
if (perc == 0)
{
MXS_ERROR("Weighting parameter '%s' with a value of %d for"
" server '%s' rounds down to zero with total weight"
" of %d for service '%s'. No queries will be "
"routed to this server as long as a server with"
" positive weight is available.",
weightby, wght, server->server->unique_name,
total, service->name);
}
else if (perc < 0)
{
MXS_ERROR("Weighting parameter '%s' for server '%s' is too large, "
"maximum value is %d. No weighting will be used for this "
"server.", weightby, server->server->unique_name,
INT_MAX / SERVICE_BASE_SERVER_WEIGHT);
perc = SERVICE_BASE_SERVER_WEIGHT;
}
server->weight = perc;
}
else
{
MXS_WARNING("Server '%s' has no parameter '%s' used for weighting"
" for service '%s'.", server->server->unique_name,
weightby, service->name);
}
}
}
}
}