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Added router_option slave_selection_criteria=[LEAST_GLOBAL_CONNECTIONS(default)|LEAST_BEHIND_MASTER] to readwritesplit section.

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The option is reloadable in the same way as max_slave_connections parameter. Option value determines which sort function is called before to sort backend server pointers before selecting them and establishing connections to backends.
This commit is contained in:
VilhoRaatikka 2014-05-11 23:59:16 +03:00
parent b8618ee7cf
commit b7ae1c1784
3 changed files with 106 additions and 34 deletions
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4
server/core/config.c
View File

@ -858,7 +858,9 @@ SERVER *server;
char *auth;
char *enable_root_user;
enable_root_user = config_get_value(obj->parameters, "enable_root_user");
enable_root_user =
config_get_value(obj->parameters,
"enable_root_user");
user = config_get_value(obj->parameters,
"user");

19
server/modules/include/readwritesplit.h
View File

@ -50,9 +50,23 @@ typedef enum rses_property_type_t {
RSES_PROP_TYPE_COUNT=RSES_PROP_TYPE_LAST+1
} rses_property_type_t;
typedef enum select_criteria {
UNDEFINED_CRITERIA=0,
LEAST_GLOBAL_CONNECTIONS,
DEFAULT_CRITERIA=LEAST_GLOBAL_CONNECTIONS,
LEAST_BEHIND_MASTER
} select_criteria_t;
/** default values for rwsplit configuration parameters */
#define CONFIG_MAX_SLAVE_CONN 1
#define GET_SELECT_CRITERIA(s) \
(strncmp(s,"LEAST_GLOBAL_CONNECTIONS", strlen("LEAST_GLOBAL_CONNECTIONS")) == 0 ? \
LEAST_GLOBAL_CONNECTIONS : ( \
strncmp(s,"LEAST_BEHIND_MASTER", strlen("LEAST_BEHIND_MASTER")) == 0 ? \
LEAST_BEHIND_MASTER : UNDEFINED_CRITERIA))
/**
* Session variable command
*/
@ -142,8 +156,9 @@ typedef struct backend_ref_st {
typedef struct rwsplit_config_st {
int rw_max_slave_conn_percent;
int rw_max_slave_conn_count;
int rw_max_slave_conn_percent;
int rw_max_slave_conn_count;
select_criteria_t rw_slave_select_criteria;
} rwsplit_config_t;

117
server/modules/routing/readwritesplit/readwritesplit.c
View File

@ -70,7 +70,11 @@ static void clientReply(
DCB* backend_dcb);
static uint8_t getCapabilities (ROUTER* inst, void* router_session);
int bref_cmp(
int bref_cmp_global_conn(
const void* bref1,
const void* bref2);
int bref_cmp_behind_master(
const void* bref1,
const void* bref2);
@ -79,6 +83,7 @@ static bool select_connect_backend_servers(
backend_ref_t* backend_ref,
int router_nservers,
int max_nslaves,
select_criteria_t select_criteria,
SESSION* session,
ROUTER_INSTANCE* router);
@ -87,6 +92,11 @@ static bool get_dcb(
ROUTER_CLIENT_SES* rses,
backend_type_t btype);
static void rwsplit_process_options(
ROUTER_INSTANCE* router,
char** options);
static ROUTER_OBJECT MyObject = {
createInstance,
@ -282,15 +292,6 @@ static ROUTER* createInstance(
free(router);
return NULL;
}
if (options != NULL)
{
LOGIF(LM, (skygw_log_write(
LOGFILE_MESSAGE,
"Router options supplied to read/write statement router "
"module but none are supported. The options will be "
"ignored.")));
}
/**
* Create an array of the backend servers in the router structure to
* maintain a count of the number of connections to each
@ -335,30 +336,20 @@ static ROUTER* createInstance(
router->bitvalue = 0;
if (options)
{
for (i = 0; options[i]; i++)
{
if (!strcasecmp(options[i], "synced"))
{
router->bitmask |= (SERVER_JOINED);
router->bitvalue |= SERVER_JOINED;
}
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Warning : Unsupported "
"router option \"%s\" "
"for readwritesplit router.",
options[i])));
}
}
rwsplit_process_options(router, options);
}
/**
* Set default value for max_slave_connections.
* If parameter is set in config file this setting will be overwritten.
* Set default value for max_slave_connections and for slave selection
* criteria. If parameter is set in config file max_slave_connections
* will be overwritten.
*/
router->rwsplit_config.rw_max_slave_conn_count = CONFIG_MAX_SLAVE_CONN;
if (router->rwsplit_config.rw_slave_select_criteria == UNDEFINED_CRITERIA)
{
router->rwsplit_config.rw_slave_select_criteria = DEFAULT_CRITERIA;
}
/**
* Copy all config parameters from service to router instance.
* Finally, copy version number to indicate that configs match.
@ -435,6 +426,8 @@ static void* newSession(
param = param->next;
}
router->rwsplit_version = router->service->svc_config_version;
/** Read options */
rwsplit_process_options(router, router->service->routerOptions);
}
/** Copy config struct from router instance */
client_rses->rses_config = router->rwsplit_config;
@ -559,6 +552,7 @@ static void* newSession(
backend_ref,
router_nservers,
max_nslaves,
client_rses->rses_config.rw_slave_select_criteria,
session,
router);
@ -1306,7 +1300,7 @@ lock_failed:
}
int bref_cmp(
int bref_cmp_global_conn(
const void* bref1,
const void* bref2)
{
@ -1317,6 +1311,13 @@ int bref_cmp(
((b1->backend_conn_count > b2->backend_conn_count) ? 1 : 0));
}
int bref_cmp_behind_master(
const void* bref1,
const void* bref2)
{
return 1;
}
/**
* @node Search suitable backend servers from those of router instance.
*
@ -1352,6 +1353,7 @@ static bool select_connect_backend_servers(
backend_ref_t* backend_ref,
int router_nservers,
int max_nslaves,
select_criteria_t select_criteria,
SESSION* session,
ROUTER_INSTANCE* router)
{
@ -1363,6 +1365,7 @@ static bool select_connect_backend_servers(
int i;
const int min_nslaves = 0; /*< not configurable at the time */
bool is_synced_master;
int (*p)(const void *, const void *);
if (p_master_ref == NULL || backend_ref == NULL)
{
@ -1370,6 +1373,22 @@ static bool select_connect_backend_servers(
succp = false;
goto return_succp;
}
/** Check slave selection criteria and set compare function */
switch (select_criteria) {
case LEAST_GLOBAL_CONNECTIONS:
p = bref_cmp_global_conn;
break;
case LEAST_BEHIND_MASTER:
p = bref_cmp_behind_master;
break;
default:
succp = false;
goto return_succp;
break;
}
if (router->bitvalue != 0) /*< 'synced' is the only bitvalue in rwsplit */
{
@ -1397,7 +1416,7 @@ static bool select_connect_backend_servers(
* a consequence those backends having least connections are in the
* beginning of the list.
*/
qsort((void *)backend_ref, (size_t)router_nservers, sizeof(backend_ref_t), bref_cmp);
qsort((void *)backend_ref, (size_t)router_nservers, sizeof(backend_ref_t), p);
LOGIF(LT, (skygw_log_write(LOGFILE_TRACE, "Servers and conns after ordering:")));
@ -2324,3 +2343,39 @@ return_succp:
return succp;
}
static void rwsplit_process_options(
ROUTER_INSTANCE* router,
char** options)
{
int i;
char* value;
for (i = 0; options[i]; i++)
{
if ((value = strchr(options[i], '=')) == NULL)
{
LOGIF(LE, (skygw_log_write(
LOGFILE_ERROR, "Warning : Unsupported "
"router option \"%s\" for "
"readwritesplit router.",
options[i])));
}
else
{
*value = 0;
value++;
if (strcmp(options[i], "slave_selection_criteria") == 0)
{
router->rwsplit_config.rw_slave_select_criteria =
GET_SELECT_CRITERIA(value);
ss_dassert(
router->rwsplit_config.rw_slave_select_criteria ==
LEAST_GLOBAL_CONNECTIONS ||
router->rwsplit_config.rw_slave_select_criteria ==
LEAST_BEHIND_MASTER ||
router->rwsplit_config.rw_slave_select_criteria ==
UNDEFINED_CRITERIA);
}
}
}
}