Add configuration options for tuning MapCache connection pool

Author: jbo-ads

apache/mod_mapcache.c

@@ -312,15 +312,15 @@ static void mod_mapcache_child_init(apr_pool_t *pool, server_rec *s)
     int i,rv;
     for(i=0;i<cfg->aliases->nelts;i++) {
       mapcache_alias_entry *alias_entry = APR_ARRAY_IDX(cfg->aliases,i,mapcache_alias_entry*);
-      rv = mapcache_connection_pool_create(&(alias_entry->cp),pool);
+      rv = mapcache_connection_pool_create(alias_entry->cfg, &(alias_entry->cp),pool);
       ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "creating a child process mapcache connection pool on server %s for alias %s", s->server_hostname, alias_entry->endpoint);
       if(rv!=APR_SUCCESS) {
         ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s, "failed to create mapcache connection pool");
       }
     }
     for(i=0;i<cfg->quickaliases->nelts;i++) {
       mapcache_alias_entry *alias_entry = APR_ARRAY_IDX(cfg->quickaliases,i,mapcache_alias_entry*);
-      rv = mapcache_connection_pool_create(&(alias_entry->cp),pool);
+      rv = mapcache_connection_pool_create(alias_entry->cfg, &(alias_entry->cp),pool);
       ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, "creating a child process mapcache connection pool on server %s for alias %s", s->server_hostname, alias_entry->endpoint);
       if(rv!=APR_SUCCESS) {
         ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s, "failed to create mapcache connection pool");

cgi/mapcache.c

@@ -210,7 +210,7 @@ static void load_config(mapcache_context *ctx, char *filename)
     apr_pool_destroy(config_pool);
   }
   config_pool = tmp_config_pool;
-  mapcache_connection_pool_create(&ctx->connection_pool, config_pool);
+  mapcache_connection_pool_create(cfg, &ctx->connection_pool, config_pool);
 
   return;
 

contrib/mapcache_detail/mapcache_detail.c

@@ -694,7 +694,7 @@ int main(int argc, char * argv[])
   mapcache_context_init(&ctx);
   ctx.config = mapcache_configuration_create(ctx.pool);
   ctx.log = mapcache_log;
-  mapcache_connection_pool_create(&ctx.connection_pool, ctx.pool);
+  mapcache_connection_pool_create(ctx.config, &ctx.connection_pool, ctx.pool);
 
 
   /////////////////////////////////////////////////////////////////////////////

include/mapcache.h

@@ -875,6 +875,12 @@ struct mapcache_cfg {
   /* return 404 on potentially blocking operations (proxying, source getmaps,
    locks on metatile waiting, ... Used for nginx module */
   int non_blocking;
+
+  // Parameters for connection_pool:
+  // - cp_hmax defines the maximum number of open connections at the same time
+  // - cp_ttl defines the maximum amount of time in microseconds an unused connection is valid
+  int cp_hmax;
+  int cp_ttl;
 };
 
 /**
@@ -1643,7 +1649,7 @@ struct mapcache_pooled_connection {
 typedef void (*mapcache_connection_constructor)(mapcache_context *ctx, void **connection, void *params);
 typedef void (*mapcache_connection_destructor)(void *connection);
 
-MS_DLL_EXPORT apr_status_t mapcache_connection_pool_create(mapcache_connection_pool **cp, apr_pool_t *server_pool);
+MS_DLL_EXPORT apr_status_t mapcache_connection_pool_create(mapcache_cfg *cfg, mapcache_connection_pool **cp, apr_pool_t *server_pool);
 mapcache_pooled_connection* mapcache_connection_pool_get_connection(mapcache_context *ctx, char *key,
         mapcache_connection_constructor constructor,
         mapcache_connection_destructor destructor,

lib/configuration_xml.c

@@ -1230,6 +1230,28 @@ void mapcache_configuration_parse_xml(mapcache_context *ctx, const char *filenam
     }
   }
 
+  config->cp_hmax = 1024;
+  config->cp_ttl = 60*1000*1000;
+  if((node = ezxml_child(doc,"connection_pool")) != NULL) {
+    ezxml_t cp_param_node;
+    char *endptr;
+    if ((cp_param_node = ezxml_child(node,"max_connections")) != NULL) {
+      config->cp_hmax = (int)strtol(cp_param_node->txt,&endptr,10);
+      if (*endptr != 0 || config->cp_hmax < 0) {
+        ctx->set_error(ctx, 400, "failed to parse max_connections %s "
+            "(expecting a positive integer)", cp_param_node->txt);
+        return;
+      }
+    }
+    if ((cp_param_node = ezxml_child(node,"time_to_live_us")) != NULL) {
+      config->cp_ttl = (int)strtol(cp_param_node->txt,&endptr,10);
+      if (*endptr != 0 || config->cp_ttl < 0) {
+        ctx->set_error(ctx, 400, "failed to parse time_to_live_us %s "
+            "(expecting a positive integer)", cp_param_node->txt);
+        return;
+      }
+    }
+  }
 
 cleanup:
   ezxml_free(doc);

lib/connection_pool.c

@@ -74,11 +74,11 @@ static apr_status_t mapcache_connection_container_destructor(void *conn_, void *
 }
 
 
-apr_status_t mapcache_connection_pool_create(mapcache_connection_pool **cp, apr_pool_t *server_pool) {
+apr_status_t mapcache_connection_pool_create(mapcache_cfg *cfg, mapcache_connection_pool **cp, apr_pool_t *server_pool) {
   apr_status_t rv;
   *cp = apr_pcalloc(server_pool, sizeof(mapcache_connection_pool));
   (*cp)->server_pool = server_pool;
-  rv = apr_reslist_create(&((*cp)->connexions), 1, 5, 1024, 60*1000000,
+  rv = apr_reslist_create(&((*cp)->connexions), 1, 5, cfg->cp_hmax, cfg->cp_ttl,
       mapcache_connection_container_creator,
       mapcache_connection_container_destructor,
       NULL,

nginx/ngx_http_mapcache_module.c

@@ -300,7 +300,7 @@ ngx_http_mapcache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "no mapcache <service>s configured/enabled, no point in continuing.");
     return NGX_CONF_ERROR;
   }
-  mapcache_connection_pool_create(&ctx->connection_pool,ctx->pool);
+  mapcache_connection_pool_create(ctx->config, &ctx->connection_pool,ctx->pool);
   ctx->config->non_blocking = 1;
 
   ngx_http_core_loc_conf_t  *clcf;

util/mapcache_seed.c

@@ -1120,7 +1120,7 @@ int main(int argc, const char **argv)
     mapcache_configuration_post_config(&ctx,cfg);
     if(ctx.get_error(&ctx))
       return usage(argv[0],ctx.get_error_message(&ctx));
-    mapcache_connection_pool_create(&ctx.connection_pool, ctx.pool);
+    mapcache_connection_pool_create(cfg, &ctx.connection_pool, ctx.pool);
   }
 
 #ifdef USE_CLIPPERS