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Prevent active readwritesplit sessions from connecting to a master

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If a readwritesplit session is active, it should never connect to a new
master. This will lead to unexpected results as the session states aren't
consistent.
This commit is contained in:
Markus Makela
2016-11-05 11:31:06 +02:00
parent c30d0dfc9d
commit 3d4a7179c7
1 changed files with 21 additions and 20 deletions
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41
server/modules/routing/readwritesplit/readwritesplit.c
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@ -145,7 +145,8 @@ static bool select_connect_backend_servers(backend_ref_t **p_master_ref,
int max_rlag, int max_rlag,
select_criteria_t select_criteria, select_criteria_t select_criteria,
SESSION *session, SESSION *session,
ROUTER_INSTANCE *router); ROUTER_INSTANCE *router,
bool new_session);
static bool get_dcb(DCB **dcb, ROUTER_CLIENT_SES *rses, backend_type_t btype, static bool get_dcb(DCB **dcb, ROUTER_CLIENT_SES *rses, backend_type_t btype,
char *name, int max_rlag); char *name, int max_rlag);
@ -829,7 +830,7 @@ static void *newSession(ROUTER *router_inst, SESSION *session)
succp = select_connect_backend_servers(&master_ref, backend_ref, router_nservers, succp = select_connect_backend_servers(&master_ref, backend_ref, router_nservers,
max_nslaves, max_slave_rlag, max_nslaves, max_slave_rlag,
client_rses->rses_config.rw_slave_select_criteria, client_rses->rses_config.rw_slave_select_criteria,
session, router); session, router, false);
rses_end_locked_router_action(client_rses); rses_end_locked_router_action(client_rses);
@ -2624,7 +2625,8 @@ static void clientReply(ROUTER *instance, void *router_session, GWBUF *writebuf,
router_cli_ses->rses_config.rw_max_slave_replication_lag, router_cli_ses->rses_config.rw_max_slave_replication_lag,
router_cli_ses->rses_config.rw_slave_select_criteria, router_cli_ses->rses_config.rw_slave_select_criteria,
router_cli_ses->rses_master_ref->bref_dcb->session, router_cli_ses->rses_master_ref->bref_dcb->session,
router_cli_ses->router); router_cli_ses->router,
true);
} }
} }
/** /**
@ -3011,7 +3013,8 @@ static bool select_connect_backend_servers(backend_ref_t **p_master_ref,
int max_slave_rlag, int max_slave_rlag,
select_criteria_t select_criteria, select_criteria_t select_criteria,
SESSION *session, SESSION *session,
ROUTER_INSTANCE *router) ROUTER_INSTANCE *router,
bool active_session)
{ {
if (p_master_ref == NULL || backend_ref == NULL) if (p_master_ref == NULL || backend_ref == NULL)
{ {
@ -3032,11 +3035,16 @@ static bool select_connect_backend_servers(backend_ref_t **p_master_ref,
} }
/** /**
* Existing session : master is already chosen and connected. * New session:
* The function was called because new slave must be selected to replace *
* failed one. * Connect to both master and slaves
*
* Existing session:
*
* Master is already connected or we don't have a master. The function was
* called because new slaves must be selected to replace failed ones.
*/ */
bool master_connected = *p_master_ref != NULL; bool master_connected = active_session || *p_master_ref != NULL;
/** Check slave selection criteria and set compare function */ /** Check slave selection criteria and set compare function */
int (*p)(const void *, const void *) = criteria_cmpfun[select_criteria]; int (*p)(const void *, const void *) = criteria_cmpfun[select_criteria];
@ -3085,19 +3093,12 @@ static bool select_connect_backend_servers(backend_ref_t **p_master_ref,
} }
} }
/* take the master_host for master */ /* take the master_host for master */
else if (master_host && (serv == master_host->backend_server)) else if (!master_connected && master_host && serv == master_host->backend_server)
{ {
/** p_master_ref must be assigned with this backend_ref pointer if (connect_server(&backend_ref[i], session, false))
* because its original value may have been lost when backend
* references were sorted with qsort. */
*p_master_ref = &backend_ref[i];
if (!master_connected)
{ {
if (connect_server(&backend_ref[i], session, false)) *p_master_ref = &backend_ref[i];
{ master_connected = true;
master_connected = true;
}
} }
} }
} }
@ -4547,7 +4548,7 @@ static bool handle_error_new_connection(ROUTER_INSTANCE *inst,
router_nservers, router_nservers,
max_nslaves, max_slave_rlag, max_nslaves, max_slave_rlag,
myrses->rses_config.rw_slave_select_criteria, myrses->rses_config.rw_slave_select_criteria,
ses, inst); ses, inst, true);
} }
return_succp: return_succp: