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Posted to dev@tomcat.apache.org by mt...@apache.org on 2002/10/02 17:36:23 UTC
cvs commit: jakarta-tomcat-connectors/jk/native2/common jk_worker_lb.c
mturk 2002/10/02 08:36:22
Modified: jk/native2/common jk_worker_lb.c
Log:
Introduced 3 new configuration parameters to the lb.
1. attempts -- replaces harcoded MAX_ATTEMPTS
2. recovery -- replaces hardcoded WAIT_BEFORE_RECOVER
3. timeout -- this one is new.
The timeout if set will force the lb to cycle through workers if all are in the
error_state for the specified amount of seconds. This is usefull for
situations when the TC is overloaded and refuses new connections.
The lb will wait and after timeout will report 500 to the client.
Revision Changes Path
1.24 +36 -9 jakarta-tomcat-connectors/jk/native2/common/jk_worker_lb.c
Index: jk_worker_lb.c
===================================================================
RCS file: /home/cvs/jakarta-tomcat-connectors/jk/native2/common/jk_worker_lb.c,v
retrieving revision 1.23
retrieving revision 1.24
diff -u -r1.23 -r1.24
--- jk_worker_lb.c 8 Jul 2002 13:33:38 -0000 1.23
+++ jk_worker_lb.c 2 Oct 2002 15:36:22 -0000 1.24
@@ -77,15 +77,20 @@
#define DEFAULT_LB_FACTOR (1.0)
/* Time to wait before retry... XXX make it configurable*/
-#define WAIT_BEFORE_RECOVER (60)
+#define WAIT_BEFORE_RECOVER 60
#define MAX_ATTEMPTS 3
#define NO_WORKER_MSG "The servlet container is temporary unavailable or being upgraded\n";
typedef struct {
- struct jk_mutex *cs;
- int initializing;
+ struct jk_mutex *cs;
+ int initializing;
+ int attempts;
+ int recovery;
+ int timeout;
+ time_t error_time;
+
} jk_worker_lb_private_t;
/** Find the best worker. In process, check if timeout expired
@@ -108,6 +113,7 @@
int currentLevel=JK_LB_LEVELS - 1;
char *session_route;
time_t now = 0;
+ jk_worker_lb_private_t *lb_priv = lb->worker_private;
session_route = jk2_requtil_getSessionRoute(env, s);
@@ -119,7 +125,7 @@
if(w->route != NULL &&
0 == strcmp(session_route, w->route)) {
if(attempt > 0 && w->in_error_state) {
- /* We already tried to revive this worker. */
+ /* We already tried to revive this worker. */
break;
} else {
return w;
@@ -181,7 +187,7 @@
/* Check if it's ready for recovery */
if( now==0 ) now = time(NULL);
- if((now - w->error_time) > WAIT_BEFORE_RECOVER) {
+ if((now - w->error_time) > lb_priv->recovery) {
env->l->jkLog(env, env->l, JK_LOG_ERROR,
"lb.getWorker() reenable %s\n", w->mbean->name);
w->in_error_state = JK_FALSE;
@@ -331,7 +337,18 @@
rec=jk2_get_most_suitable_worker(env, lb, s, attempt);
if (lb_priv->cs != NULL)
- lb_priv->cs->unLock(env, lb_priv->cs);
+ lb_priv->cs->unLock(env, lb_priv->cs);
+ if (!rec && lb_priv->timeout) {
+ time_t now = time(NULL);
+ if ((int)(now - lb_priv->error_time) < lb_priv->timeout) {
+#ifdef HAS_APR
+ apr_thread_yield();
+#endif
+ continue;
+ }
+ }
+ else
+ lb_priv->error_time = time(NULL);
}
else if (!rec){
/* If we are initializing the service wait until
@@ -340,7 +357,7 @@
if (lb->cs != NULL) {
lb->cs->lock(env, lb->cs);
lb->cs->unLock(env, lb->cs);
- }
+ }
continue;
}
attempt++;
@@ -370,6 +387,7 @@
}
s->afterRequest( env, s);
+ lb_priv->error_time = time(NULL);
return JK_ERR;
}
@@ -502,6 +520,7 @@
jk_worker_t *lb=mbean->object;
char *value=valueP;
unsigned i = 0;
+ jk_worker_lb_private_t *lb_priv = lb->worker_private;
if( strcmp( name, "worker") == 0 ) {
if( lb->lbWorkerMap->get( env, lb->lbWorkerMap, name) != NULL ) {
@@ -523,7 +542,13 @@
lb->noWorkerCode=atoi( value );
} else if( strcmp( name, "hwBalanceErr") == 0 ) {
lb->hwBalanceErr=atoi( value );
- }
+ } else if( strcmp( name, "timeout") == 0 ) {
+ lb_priv->timeout=atoi( value );
+ } else if( strcmp( name, "recovery") == 0 ) {
+ lb_priv->recovery=atoi( value );
+ } else if( strcmp( name, "attempts") == 0 ) {
+ lb_priv->attempts=atoi( value );
+ }
return JK_ERR;
}
@@ -594,7 +619,9 @@
if( jkb != NULL ) {
worker_private->cs=jkb->object;
jkb->init(env, jkb );
- }
+ }
+ worker_private->attempts = MAX_ATTEMPTS;
+ worker_private->recovery = WAIT_BEFORE_RECOVER;
w->worker_private = worker_private;
w->service = jk2_lb_service;
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RE: cvs commit: jakarta-tomcat-connectors/jk/native2/common jk_worker_lb.c
Posted by Mladen Turk <mt...@mappingsoft.com>.
> -----Original Message-----
> From: mturk@apache.org
> Modified: jk/native2/common jk_worker_lb.c
> Log:
> Introduced 3 new configuration parameters to the lb.
> 1. attempts -- replaces harcoded MAX_ATTEMPTS
> 2. recovery -- replaces hardcoded WAIT_BEFORE_RECOVER
> 3. timeout -- this one is new.
> The timeout if set will force the lb to cycle through
> workers if all are in the
> error_state for the specified amount of seconds. This is usefull for
> situations when the TC is overloaded and refuses new connections.
> The lb will wait and after timeout will report 500 to the client.
>
Some more clarification:
The reason for introducing timeout inside lb is from my point of view
and the applications I'm using jk2 for, fact that even using most
powerful system, there will be situations that returns 500 to the client
simply because the TC is to busy and refuses new connections. One way to
solve that is to force the TC to allow more connections eating system
resources, and the other is using lb timeout.
One drawback of using timeout is the fact that the client will get
delayed response even for the non-existent configured TC instance.
I've made such behavior at first inside the socket connector, but Nacho
(he was right) made a strong objection to that. So instead trying to
connect to the instance from connector point of view, all that is put
inside the load balancer.
MT.
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