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Remove BACKEND structure from readwritesplit

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The BACKEND structure is no longer created for the instance. This allows
sessions to dynamically create new servers.
This commit is contained in:
Markus Makela
2016-11-03 12:00:33 +02:00
parent a097204c70
commit a163e31b9a
8 changed files with 135 additions and 225 deletions
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122
server/modules/routing/readwritesplit/readwritesplit.c
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@ -183,12 +183,7 @@ ROUTER_OBJECT *GetModuleObject()
static ROUTER *createInstance(SERVICE *service, char **options)
{
ROUTER_INSTANCE *router;
SERVER *server;
SERVER_REF *sref;
int nservers;
int i;
CONFIG_PARAMETER *param;
char *weightby;
if ((router = MXS_CALLOC(1, sizeof(ROUTER_INSTANCE))) == NULL)
{
@ -197,51 +192,6 @@ static ROUTER *createInstance(SERVICE *service, char **options)
router->service = service;
spinlock_init(&router->lock);
/** Calculate number of servers */
sref = service->dbref;
nservers = 0;
while (sref != NULL)
{
nservers++;
sref = sref->next;
}
router->servers = (BACKEND **)MXS_CALLOC(nservers + 1, sizeof(BACKEND *));
if (router->servers == NULL)
{
free_rwsplit_instance(router);
return NULL;
}
/**
* Create an array of the backend servers in the router structure to
* maintain a count of the number of connections to each
* backend server.
*/
sref = service->dbref;
nservers = 0;
while (sref != NULL)
{
if ((router->servers[nservers] = MXS_MALLOC(sizeof(BACKEND))) == NULL)
{
free_rwsplit_instance(router);
return NULL;
}
router->servers[nservers]->backend_server = sref->server;
router->servers[nservers]->backend_conn_count = 0;
router->servers[nservers]->be_valid = false;
router->servers[nservers]->weight = sref->weight;
#if defined(SS_DEBUG)
router->servers[nservers]->be_chk_top = CHK_NUM_BACKEND;
router->servers[nservers]->be_chk_tail = CHK_NUM_BACKEND;
#endif
nservers += 1;
sref = sref->next;
}
router->servers[nservers] = NULL;
/*
* Until we know otherwise assume we have some available slaves.
*/
@ -268,6 +218,13 @@ static ROUTER *createInstance(SERVICE *service, char **options)
router->rwsplit_config.rw_max_sescmd_history_size = 0;
}
int nservers = 0;
for (SERVER_REF *ref = service->dbref; ref; ref = ref->next)
{
nservers++;
}
/**
* Set default value for max_slave_connections as 100%. This way
* LEAST_CURRENT_OPERATIONS allows us to balance evenly across all the
@ -341,8 +298,7 @@ static ROUTER *createInstance(SERVICE *service, char **options)
*/
static void *newSession(ROUTER *router_inst, SESSION *session)
{
backend_ref_t
*backend_ref; /*< array of backend references (DCB,BACKEND,cursor) */
backend_ref_t *backend_ref; /*< array of backend references (DCB,BACKEND,cursor) */
backend_ref_t *master_ref = NULL; /*< pointer to selected master */
ROUTER_CLIENT_SES *client_rses = NULL;
ROUTER_INSTANCE *router = (ROUTER_INSTANCE *)router_inst;
@ -417,7 +373,8 @@ static void *newSession(ROUTER *router_inst, SESSION *session)
* Initialize backend references with BACKEND ptr.
* Initialize session command cursors for each backend reference.
*/
for (i = 0; i < router_nservers; i++)
i = 0;
for (SERVER_REF *sref = router->service->dbref; sref; sref = sref->next)
{
#if defined(SS_DEBUG)
backend_ref[i].bref_chk_top = CHK_NUM_BACKEND_REF;
@ -426,13 +383,14 @@ static void *newSession(ROUTER *router_inst, SESSION *session)
backend_ref[i].bref_sescmd_cur.scmd_cur_chk_tail = CHK_NUM_SESCMD_CUR;
#endif
backend_ref[i].bref_state = 0;
backend_ref[i].bref_backend = router->servers[i];
backend_ref[i].ref = sref;
/** store pointers to sescmd list to both cursors */
backend_ref[i].bref_sescmd_cur.scmd_cur_rses = client_rses;
backend_ref[i].bref_sescmd_cur.scmd_cur_active = false;
backend_ref[i].bref_sescmd_cur.scmd_cur_ptr_property =
&client_rses->rses_properties[RSES_PROP_TYPE_SESCMD];
backend_ref[i].bref_sescmd_cur.scmd_cur_cmd = NULL;
i++;
}
max_nslaves = rses_get_max_slavecount(client_rses, router_nservers);
max_slave_rlag = rses_get_max_replication_lag(client_rses);
@ -586,7 +544,7 @@ static void closeSession(ROUTER *instance, void *router_session)
*/
dcb_close(dcb);
/** decrease server current connection counters */
atomic_add(&bref->bref_backend->backend_conn_count, -1);
atomic_add(&bref->ref->connections, -1);
}
else
{
@ -729,7 +687,6 @@ static void diagnostics(ROUTER *instance, DCB *dcb)
ROUTER_CLIENT_SES *router_cli_ses;
ROUTER_INSTANCE *router = (ROUTER_INSTANCE *)instance;
int i = 0;
BACKEND *backend;
char *weightby;
spinlock_acquire(&router->lock);
@ -770,13 +727,12 @@ static void diagnostics(ROUTER *instance, DCB *dcb)
dcb_printf(dcb, "\t\tServer Target %% Connections "
"Operations\n");
dcb_printf(dcb, "\t\t Global Router\n");
for (i = 0; router->servers[i]; i++)
for (SERVER_REF *ref = router->service->dbref; ref; ref = ref->next)
{
backend = router->servers[i];
dcb_printf(dcb, "\t\t%-20s %3.1f%% %-6d %-6d %d\n",
backend->backend_server->unique_name, (float)backend->weight / 10,
backend->backend_server->stats.n_current, backend->backend_conn_count,
backend->backend_server->stats.n_current_ops);
ref->server->unique_name, (float)ref->weight / 10,
ref->server->stats.n_current, ref->connections,
ref->server->stats.n_current_ops);
}
}
}
@ -923,17 +879,15 @@ static void clientReply(ROUTER *instance, void *router_session, GWBUF *writebuf,
{
bool succp;
MXS_INFO("Backend %s:%d processed reply and starts to execute "
"active cursor.", bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
MXS_INFO("Backend %s:%d processed reply and starts to execute active cursor.",
bref->ref->server->name, bref->ref->server->port);
succp = execute_sescmd_in_backend(bref);
if (!succp)
{
MXS_INFO("Backend %s:%d failed to execute session command.",
bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
bref->ref->server->name, bref->ref->server->port);
}
}
else if (bref->bref_pending_cmd != NULL) /*< non-sescmd is waiting to be routed */
@ -1092,13 +1046,13 @@ void bref_clear_state(backend_ref_t *bref, bref_state_t state)
else
{
/** Decrease global operation count */
prev2 = atomic_add(&bref->bref_backend->backend_server->stats.n_current_ops, -1);
prev2 = atomic_add(&bref->ref->server->stats.n_current_ops, -1);
ss_dassert(prev2 > 0);
if (prev2 <= 0)
{
MXS_ERROR("[%s] Error: negative current operation count in backend %s:%u",
__FUNCTION__, bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
__FUNCTION__, bref->ref->server->name,
bref->ref->server->port);
}
}
}
@ -1137,19 +1091,16 @@ void bref_set_state(backend_ref_t *bref, bref_state_t state)
if (prev1 < 0)
{
MXS_ERROR("[%s] Error: negative number of connections waiting for "
"results in backend %s:%u",
__FUNCTION__, bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
"results in backend %s:%u", __FUNCTION__,
bref->ref->server->name, bref->ref->server->port);
}
/** Increase global operation count */
prev2 =
atomic_add(&bref->bref_backend->backend_server->stats.n_current_ops, 1);
prev2 = atomic_add(&bref->ref->server->stats.n_current_ops, 1);
ss_dassert(prev2 >= 0);
if (prev2 < 0)
{
MXS_ERROR("[%s] Error: negative current operation count in backend %s:%u",
__FUNCTION__, bref->bref_backend->backend_server->name,
bref->bref_backend->backend_server->port);
__FUNCTION__, bref->ref->server->name, bref->ref->server->port);
}
}
@ -1316,7 +1267,7 @@ int router_handle_state_switch(DCB *dcb, DCB_REASON reason, void *data)
bref = (backend_ref_t *)data;
CHK_BACKEND_REF(bref);
srv = bref->bref_backend->backend_server;
srv = bref->ref->server;
if (SERVER_IS_RUNNING(srv) && SERVER_IS_IN_CLUSTER(srv))
{
@ -1531,9 +1482,9 @@ static void handleError(ROUTER *instance, void *router_session,
* handled so that session could continue.
*/
if (rses->rses_master_ref && rses->rses_master_ref->bref_dcb == problem_dcb &&
!SERVER_IS_MASTER(rses->rses_master_ref->bref_backend->backend_server))
!SERVER_IS_MASTER(rses->rses_master_ref->ref->server))
{
SERVER *srv = rses->rses_master_ref->bref_backend->backend_server;
SERVER *srv = rses->rses_master_ref->ref->server;
backend_ref_t *bref;
bref = get_bref_from_dcb(rses, problem_dcb);
if (bref != NULL)
@ -1794,9 +1745,8 @@ return_succp:
static int router_get_servercount(ROUTER_INSTANCE *inst)
{
int router_nservers = 0;
BACKEND **b = inst->servers;
/** count servers */
while (*(b++) != NULL)
for (SERVER_REF *ref = inst->service->dbref; ref; ref = ref->next)
{
router_nservers++;
}
@ -2074,14 +2024,6 @@ static void free_rwsplit_instance(ROUTER_INSTANCE *router)
{
if (router)
{
if (router->servers)
{
for (int i = 0; router->servers[i]; i++)
{
MXS_FREE(router->servers[i]);
}
}
MXS_FREE(router->servers);
MXS_FREE(router);
}
}