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config.h: Added enumerated types MAX_RLAG_AVAILABLE and MAX_RLAG_UNDEFINED to be used instead of magic numbers as max_slave_replication_lag values.

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readwritesplit.h: Added TARGET_RLAG_MAX to the list of hint targets. It is used in case of hint max_slave_replication_lag=<value>
readwritesplit.c: get_dcb is called when readwritesplit router chooses target backend for a query. Backend is selected from those the router has connection to. get_dcb now takes additional parameters, name and max_rlag. Name is used if there is a hint route to server <server name>. max_rlag is used for hint max_slave_replication_lag=<value> or if it doesn't exist, then for configure parameter max_slave_replication_lag=<configured value> or if both are absent, ignored.
This commit is contained in:
VilhoRaatikka
2014-08-01 16:33:29 +03:00
parent 4f3d746f4e
commit 65b121889b
3 changed files with 74 additions and 20 deletions
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88
server/modules/routing/readwritesplit/readwritesplit.c
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@ -160,7 +160,8 @@ static bool get_dcb(
DCB** dcb,
ROUTER_CLIENT_SES* rses,
backend_type_t btype,
char* name);
char* name,
int max_rlag);
static void rwsplit_process_router_options(
ROUTER_INSTANCE* router,
@ -388,7 +389,7 @@ static void refreshInstance(
* used in slave selection.
*/
if (!rlag_enabled)
{
{
if (rlag_limited)
{
LOGIF(LE, (skygw_log_write_flush(
@ -934,7 +935,8 @@ static bool get_dcb(
DCB** p_dcb,
ROUTER_CLIENT_SES* rses,
backend_type_t btype,
char* name)
char* name,
int max_rlag)
{
backend_ref_t* backend_ref;
int smallest_nconn = -1;
@ -951,7 +953,7 @@ static bool get_dcb(
}
backend_ref = rses->rses_backend_ref;
/* get root master from available servers */
/** get root master from available servers */
master_host = get_root_master(backend_ref, rses->rses_nbackends);
if (btype == BE_SLAVE)
@ -975,6 +977,9 @@ static bool get_dcb(
b->backend_server->unique_name,
MIN(strlen(b->backend_server->unique_name), PATH_MAX)) == 0) &&
master_host != NULL &&
(max_rlag == MAX_RLAG_UNDEFINED ||
(b->backend_server->rlag != MAX_RLAG_NOT_AVAILABLE &&
b->backend_server->rlag <= max_rlag)) &&
(SERVER_IS_SLAVE(b->backend_server) ||
SERVER_IS_RELAY_SERVER(b->backend_server) ||
SERVER_IS_MASTER(b->backend_server)))
@ -1004,6 +1009,9 @@ static bool get_dcb(
if (BREF_IS_IN_USE((&backend_ref[i])) &&
master_host != NULL &&
b->backend_server != master_host->backend_server &&
(max_rlag == MAX_RLAG_UNDEFINED ||
(b->backend_server->rlag != MAX_RLAG_NOT_AVAILABLE &&
b->backend_server->rlag <= max_rlag)) &&
(SERVER_IS_SLAVE(b->backend_server) ||
SERVER_IS_RELAY_SERVER(b->backend_server)) &&
(smallest_nconn == -1 ||
@ -1100,8 +1108,25 @@ static route_target_t get_route_target (
{
/** not implemented */
}
else if (hint->type == HINT_PARAMETER)
{
if (strncasecmp(
(char *)hint->data,
"max_replication_lag",
strlen("max_replication_lag")) == 0)
{
target |= TARGET_RLAG_MAX;
}
else
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Warning : Unknown routing parameter hint : %s",
(char *)hint->data)));
}
}
hint = hint->next;
}
} /*< while (hint != NULL) */
}
else
{
@ -1343,6 +1368,7 @@ static int routeQuery(
bool succp = true;
HINT* hint;
char* named_server = NULL;
int rlag_max = MAX_RLAG_UNDEFINED;
if (router_cli_ses->rses_transaction_active) /*< all to master */
{
@ -1362,25 +1388,45 @@ static int routeQuery(
if (TARGET_IS_SLAVE(route_target))
{
if (TARGET_IS_NAMED_SERVER(route_target))
if (TARGET_IS_NAMED_SERVER(route_target) ||
TARGET_IS_RLAG_MAX(route_target))
{
hint = querybuf->hint;
while (hint != NULL &&
hint->type != HINT_ROUTE_TO_NAMED_SERVER)
while (hint != NULL)
{
if (hint->type == HINT_ROUTE_TO_NAMED_SERVER)
{
named_server = hint->data;
}
else if (hint->type == HINT_PARAMETER &&
(strncasecmp(
(char *)hint->data,
"max_replication_lag",
strlen("max_replication_lag")) == 0))
{
int val = (int) strtol((char *)hint->data,
(char **)NULL, 10);
if (val != 0 || errno == 0)
{
rlag_max = val;
}
}
hint = hint->next;
}
if (hint != NULL)
{
named_server = hint->data;
}
}
if (rlag_max == MAX_RLAG_UNDEFINED) /*< no rlag max hint, use config */
{
rlag_max = rses_get_max_replication_lag(router_cli_ses);
}
succp = get_dcb(&target_dcb,
router_cli_ses,
BE_SLAVE,
named_server);
named_server,
rlag_max);
}
else if (TARGET_IS_MASTER(route_target))
{
@ -1389,7 +1435,8 @@ static int routeQuery(
succp = get_dcb(&master_dcb,
router_cli_ses,
BE_MASTER,
NULL);
NULL,
MAX_RLAG_UNDEFINED);
}
target_dcb = master_dcb;
}
@ -1964,7 +2011,9 @@ static bool select_connect_backend_servers(
#endif
/* assert with master_host */
ss_dassert(!master_connected ||
(master_host && ((*p_master_ref)->bref_backend->backend_server == master_host->backend_server) && SERVER_MASTER));
(master_host &&
((*p_master_ref)->bref_backend->backend_server == master_host->backend_server) &&
SERVER_MASTER));
/**
* Sort the pointer list to servers according to connection counts. As
* a consequence those backends having least connections are in the
@ -2024,7 +2073,8 @@ static bool select_connect_backend_servers(
}
}
}
}
} /*< log only */
/**
* Choose at least 1+min_nslaves (master and slave) and at most 1+max_nslaves
* servers from the sorted list. First master found is selected.
@ -2041,8 +2091,8 @@ static bool select_connect_backend_servers(
{
/* check also for relay servers and don't take the master_host */
if (slaves_found < max_nslaves &&
(max_slave_rlag == -2 ||
(b->backend_server->rlag != -1 && /*< information currently not available */
(max_slave_rlag == MAX_RLAG_UNDEFINED ||
(b->backend_server->rlag != MAX_RLAG_NOT_AVAILABLE &&
b->backend_server->rlag <= max_slave_rlag)) &&
(SERVER_IS_SLAVE(b->backend_server) || SERVER_IS_RELAY_SERVER(b->backend_server)) &&
(master_host != NULL && (b->backend_server != master_host->backend_server)))