diff --git a/platform/src/proxy.cpp b/platform/src/proxy.cpp
index 4c9e084..c1fa512 100644
--- a/platform/src/proxy.cpp
+++ b/platform/src/proxy.cpp
@@ -137,7 +137,7 @@ void tfe_proxy_free(tfe_proxy * ctx)
 
 static void __dummy_event_handler(evutil_socket_t fd, short what, void * arg)
 {
-	printf("%s alive\n",__FUNCTION__);
+	//printf("%s alive\n",__FUNCTION__);
 	return;
 }
 
@@ -191,7 +191,7 @@ static void * tfe_work_thread(void * arg)
 	ctx->running = 1;
 	__currect_thread_id = ctx->thread_id;
 	char thread_name[16];
-	snprintf(thread_name, sizeof(thread_name), "tfe:worker%d", ctx->thread_id);
+	snprintf(thread_name, sizeof(thread_name), "tfe:worker-%d", ctx->thread_id);
 	prctl(PR_SET_NAME,(unsigned long long)thread_name,NULL,NULL,NULL);
 
 	TFE_LOG_INFO(g_default_logger, "Work thread %u is running...", ctx->thread_id);
diff --git a/platform/src/ssl_stream.cpp b/platform/src/ssl_stream.cpp
index d690468..6a17ec1 100644
--- a/platform/src/ssl_stream.cpp
+++ b/platform/src/ssl_stream.cpp
@@ -854,7 +854,15 @@ void ssl_stream_log_error(struct bufferevent * bev, enum tfe_conn_dir dir, void*
 	unsigned long sslerr=0;
 	int fd=bufferevent_getfd(bev);
 	struct tfe_stream_addr* addr=tfe_stream_addr_create_by_fd(fd, dir);
-	char* addr_string=tfe_stream_addr_to_str(addr);
+	char* addr_string=NULL;
+	if(addr)
+	{
+		addr_string=tfe_stream_addr_to_str(addr);
+	}
+	else
+	{
+		addr_string=tfe_strdup("null");
+	}
 
 	/* Can happen for socket errs, ssl errs;
 	 * may happen for unclean ssl socket shutdowns. */
@@ -1046,7 +1054,12 @@ extern void ssl_async_upstream_create(struct future * f, struct ssl_mgr * mgr, e
 
 	ctx->addrlen = sizeof(ctx->addr);
 	ret = getpeername(fd_upstream, (struct sockaddr *)&(ctx->addr), &(ctx->addrlen));
-	assert(ret == 0);
+	if(ret!=0)
+	{
+		ssl_connect_server_ctx_free(ctx);
+		promise_failed(p, FUTURE_ERROR_EXCEPTION, "upstream fd closed");
+		return;
+	}
 
 	ctx->fd_downstream = fd_downstream;
 	ctx->fd_upstream = fd_upstream;
diff --git a/plugin/business/pangu-http/src/pangu_web_cache.cpp b/plugin/business/pangu-http/src/pangu_web_cache.cpp
index 1a28b01..a3112eb 100644
--- a/plugin/business/pangu-http/src/pangu_web_cache.cpp
+++ b/plugin/business/pangu-http/src/pangu_web_cache.cpp
@@ -17,18 +17,22 @@ enum cache_stat_field
 {
 	STAT_CACHE_QUERY,
 	STAT_CACHE_QUERY_NOT_APPLICABLE,
+	STAT_CACHE_QUERY_VERIFY,
 	STAT_CACHE_QUERY_HIT,
 	STAT_CACHE_QUERY_BYTES,
 	STAT_CACHE_OVERRIDE_QUERY,
 	STAT_CACHE_OVERRIDE_HIT,	
 	STAT_CACHE_OVERRIDE_BYTES,
 	STAT_CACHE_QUERY_ERR,
+	STAT_CACHE_QUERY_ABANDON,
+	STAT_CACHE_QUERYING,
 	STAT_CACHE_UPLOAD_CNT,
 	STAT_CACHE_UPLOAD_OVERRIDE,
 	STAT_CACHE_UPLOAD_FORBIDEN,
 	STAT_CACHE_UPLOAD_ABANDON,
 	STAT_CACHE_UPLOAD_ERR,
 	STAT_CACHE_UPLOAD_BYTES,
+	STAT_CACHE_UPLOADING,
 	STAT_CACHE_MEMORY,
 	STAT_CACHE_ACTIVE_SESSION,
 
@@ -46,7 +50,10 @@ struct cache_handle
 	size_t cache_undefined_obj_min_size;
 	int minimum_cache_seconds;
 	struct tango_cache_instance **clients;
-	
+
+	long long get_concurrency_max;
+	long long put_concurrency_max;
+
 	screen_stat_handle_t fs_handle;
 	long long stat_val[__CACHE_STAT_MAX];
 	int fs_id[__CACHE_STAT_MAX];
@@ -144,18 +151,22 @@ void cache_stat_init(struct cache_handle* cache)
 	
 	set_stat_spec(&spec[STAT_CACHE_QUERY], "cache_get",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_QUERY_NOT_APPLICABLE], "get_not_allow",FS_STYLE_FIELD, FS_CALC_CURRENT);
+	set_stat_spec(&spec[STAT_CACHE_QUERY_VERIFY], "get_verify",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_QUERY_HIT], "hit_num",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_QUERY_BYTES], "downloaded(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_QUERY], "or_qry",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_HIT], "or_hit",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_OVERRIDE_BYTES], "or_download(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_QUERY_ERR], "get_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
+	set_stat_spec(&spec[STAT_CACHE_QUERY_ABANDON], "get_abandon",FS_STYLE_STATUS, FS_CALC_CURRENT);
+	set_stat_spec(&spec[STAT_CACHE_QUERYING], "getting",FS_STYLE_STATUS, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_CNT], "cache_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_OVERRIDE], "or_put",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_FORBIDEN], "put_forbid",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ABANDON], "put_abandon",FS_STYLE_FIELD, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_ERR], "put_err",FS_STYLE_STATUS, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_UPLOAD_BYTES], "put(MB)",FS_STYLE_FIELD, FS_CALC_CURRENT);
+	set_stat_spec(&spec[STAT_CACHE_UPLOADING], "putting",FS_STYLE_STATUS, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_MEMORY], "used_mem(MB)",FS_STYLE_STATUS, FS_CALC_CURRENT);
 	set_stat_spec(&spec[STAT_CACHE_ACTIVE_SESSION], "active_sess",FS_STYLE_STATUS, FS_CALC_CURRENT);
 
@@ -215,6 +226,11 @@ struct cache_handle* create_web_cache_handle(const char* profile_path, const cha
 			goto error_out;
 		}
 	}
+	
+	MESA_load_profile_int_def(profile_path, section, "get_concurrency_max", &temp, 1000*1000);
+	cache->put_concurrency_max=temp;
+	MESA_load_profile_int_def(profile_path, section, "put_concurrency_max", &(temp), 1000*1000);
+	cache->put_concurrency_max=temp;
 	MESA_load_profile_int_def(profile_path, section, "query_undefined_obj", &(cache->query_undefined_obj_enabled), 1);
 	MESA_load_profile_int_def(profile_path, section, "cache_undefined_obj", &(cache->cache_undefined_obj_enabled), 1);
 	MESA_load_profile_int_def(profile_path, section, "cached_undefined_obj_minimum_size", &(temp), 100*1024);
@@ -334,6 +350,7 @@ static void wrap_cache_query_on_succ(future_result_t * result, void * user)
 			//last call.			
 			promise_dettach_ctx(p);
 			cache_query_ctx_free_cb(ctx);
+			ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
 			break;
 		case RESULT_TYPE_BODY:
 			ATOMIC_ADD(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERY_BYTES]), _result->size);
@@ -349,7 +366,8 @@ static void wrap_cache_query_on_fail(enum e_future_error err, const char * what,
 {
 	struct promise * p = (struct promise *) user;
 	struct cache_query_context* ctx=(struct cache_query_context*)promise_dettach_ctx(p);
-	promise_failed(p, err, what);
+	promise_failed(p, err, what);	
+	ATOMIC_DEC(&(ctx->ref_handle->stat_val[STAT_CACHE_QUERYING]));	
 	cache_query_ctx_free_cb(ctx);
 	return;
 }
@@ -375,17 +393,24 @@ enum cache_query_status async_web_cache_query(struct cache_handle* handle, unsig
 			is_undefined_obj=1;
 			ATOMIC_INC(&(handle->stat_val[STAT_CACHE_OVERRIDE_QUERY]));
 			break;
+		case VERIFY:
+			ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_VERIFY]));
+			return WEB_CACHE_NOT_APPLICABLE;
 		case FORBIDDEN:
 			ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_NOT_APPLICABLE]));
 			return WEB_CACHE_NOT_APPLICABLE;
-		case VERIFY:
 		case ALLOWED:
 			break;
 		default:
 			assert(0);
 			return WEB_CACHE_NOT_APPLICABLE;
 	}
-	
+	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_QUERYING])) > ATOMIC_READ(&(handle->put_concurrency_max)))
+	{		
+		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERY_ABANDON]));	
+		return WEB_CACHE_NOT_APPLICABLE;
+	}
+	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_QUERYING]));	
 	struct tango_cache_meta_get meta;
 	memset(&meta, 0, sizeof(meta));
 	meta.url=request->req_spec.url;
@@ -394,6 +419,7 @@ enum cache_query_status async_web_cache_query(struct cache_handle* handle, unsig
 	query_ctx->ref_handle=handle;
 	query_ctx->url=tfe_strdup(request->req_spec.url);
 	query_ctx->is_undefined_obj=is_undefined_obj;
+
 	p=future_to_promise(f);
 	promise_set_ctx(p, query_ctx, cache_query_ctx_free_cb);
 	query_ctx->f_tango_cache_fetch=future_create("_cache_get", wrap_cache_query_on_succ, wrap_cache_query_on_fail, p);
@@ -465,6 +491,12 @@ struct cache_update_context* web_cache_update_start(struct cache_handle* handle,
 			assert(0);
 			break;
 	}
+	if(ATOMIC_READ(&(handle->stat_val[STAT_CACHE_UPLOADING])) > handle->get_concurrency_max)
+	{		
+		ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOAD_ABANDON]));	
+		return NULL;
+	}
+	ATOMIC_INC(&(handle->stat_val[STAT_CACHE_UPLOADING]));		
 	struct tango_cache_meta_put meta;
 	memset(&meta, 0, sizeof(meta));
 	meta.url=session->req->req_spec.url;
@@ -508,6 +540,7 @@ void web_cache_update_end(struct cache_update_context* ctx)
 {
 	tango_cache_update_end(ctx->write_ctx);
 	free(ctx);
+	ATOMIC_DEC(&(ctx->ref_cache_handle->stat_val[STAT_CACHE_UPLOADING]));		
 	return;
 }