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This commit is contained in:
vraatikka
2013-08-14 11:27:14 +03:00
parent eba81f0501 fbc311730c
commit 4051796653
9 changed files with 61 additions and 290 deletions
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4
server/modules/include/readconnection.h
View File

@ -37,8 +37,8 @@
* that is required for each of the backend servers.
*/
typedef struct backend {
SERVER *server; /**< The server itself */
int count; /**< Number of connections to the server */
SERVER *server; /**< The server itself */
int current_connection_count; /**< Number of connections to the server */
} BACKEND;
/**

90
server/modules/routing/readconnroute.c
View File

@ -59,6 +59,7 @@
* 22/07/2013 Mark Riddoch Addition of joined router option for Galera
* clusters
* 31/07/2013 Massimiliano Pinto Added a check for candidate server, if NULL return
* 12/08/2013 Mark Riddoch Log unsupported router options
*
* @endverbatim
*/
@ -186,7 +187,7 @@ int i, n;
return NULL;
}
inst->servers[n]->server = server;
inst->servers[n]->count = 0;
inst->servers[n]->current_connection_count = 0;
n++;
}
inst->servers[n] = NULL;
@ -215,6 +216,11 @@ int i, n;
inst->bitmask |= (SERVER_JOINED);
inst->bitvalue |= SERVER_JOINED;
}
else
{
skygw_log_write(LOGFILE_ERROR,
"Unsupported router option %s for readconnroute\n", options[i]);
}
}
}
@ -246,8 +252,7 @@ CLIENT_SESSION *client;
BACKEND *candidate = NULL;
int i;
if ((client = (CLIENT_SESSION *)malloc(sizeof(CLIENT_SESSION))) == NULL)
{
if ((client = (CLIENT_SESSION *)malloc(sizeof(CLIENT_SESSION))) == NULL) {
return NULL;
}
/*
@ -256,23 +261,6 @@ int i;
* connection router.
*/
/* First find a running server to set as our initial candidate server */
for (i = 0; inst->servers[i]; i++)
{
if (inst->servers[i] && SERVER_IS_RUNNING(inst->servers[i]->server)
&& (inst->servers[i]->server->status & inst->bitmask) == inst->bitvalue)
{
candidate = inst->servers[i];
skygw_log_write(
LOGFILE_TRACE,
"Selected server in port %d to as candidate. "
"Connections : %d\n",
candidate->server->port,
candidate->count);
break;
}
}
/*
* Loop over all the servers and find any that have fewer connections than our
* candidate server.
@ -285,33 +273,40 @@ int i;
* become the new candidate. This has the effect of spreading the connections
* over different servers during periods of very low load.
*/
for (i = 1; inst->servers[i]; i++)
{
skygw_log_write(
LOGFILE_TRACE,
"Examine server in port %d with %d connections. Status is %d, "
"inst->bitvalue is %d",
inst->servers[i]->server->port,
inst->servers[i]->count,
inst->servers[i]->server->status,
inst->bitmask);
for (i = 0; inst->servers[i]; i++) {
if(inst->servers[i]) {
skygw_log_write(
LOGFILE_TRACE,
"Examine server in port %d with %d connections. Status is %d, "
"inst->bitvalue is %d",
inst->servers[i]->server->port,
inst->servers[i]->current_connection_count,
inst->servers[i]->server->status,
inst->bitmask);
}
if (inst->servers[i] && SERVER_IS_RUNNING(inst->servers[i]->server)
&& (inst->servers[i]->server->status & inst->bitmask) == inst->bitvalue)
{
if (inst->servers[i]->count < candidate->count)
{
candidate = inst->servers[i];
if (inst->servers[i] && SERVER_IS_RUNNING(inst->servers[i]->server)
&& (inst->servers[i]->server->status & inst->bitmask) == inst->bitvalue) {
/* If no candidate set, set first running server as
our initial candidate server */
if (candidate == NULL) {
candidate = inst->servers[i];
} else if (inst->servers[i]->current_connection_count < candidate->current_connection_count) {
/* This running server has fewer
connections, set it as a new candidate */
candidate = inst->servers[i];
} else if (inst->servers[i]->current_connection_count == candidate->current_connection_count &&
inst->servers[i]->server->stats.n_connections
< candidate->server->stats.n_connections) {
/* This running server has the same number
of connections currently as the candidate
but has had fewer connections over time
than candidate, set this server to candidate*/
candidate = inst->servers[i];
}
else if (inst->servers[i]->count == candidate->count &&
inst->servers[i]->server->stats.n_connections
< candidate->server->stats.n_connections)
{
candidate = inst->servers[i];
}
}
}
/* no candidate server here, clean and return NULL */
if (!candidate) {
free(client);
@ -322,15 +317,16 @@ int i;
* We now have the server with the least connections.
* Bump the connection count for this server
*/
atomic_add(&candidate->count, 1);
atomic_add(&candidate->current_connection_count, 1);
client->backend = candidate;
skygw_log_write(
LOGFILE_TRACE,
"Final selection is server in port %d. "
"Connections : %d\n",
candidate->server->port,
candidate->count);
candidate->current_connection_count);
/*
* Open a backend connection, putting the DCB for this
* connection in the client->dcb
@ -339,7 +335,7 @@ int i;
if ((client->dcb = dcb_connect(candidate->server, session,
candidate->server->protocol)) == NULL)
{
atomic_add(&candidate->count, -1);
atomic_add(&candidate->current_connection_count, -1);
free(client);
return NULL;
}
@ -371,7 +367,7 @@ CLIENT_SESSION *session = (CLIENT_SESSION *)router_session;
* Close the connection to the backend
*/
session->dcb->func.close(session->dcb);
atomic_add(&session->backend->count, -1);
atomic_add(&session->backend->current_connection_count, -1);
atomic_add(&session->backend->server->stats.n_current, -1);
spinlock_acquire(&inst->lock);