add limits to simo open sql handles

conf/autoload_configs/switch.conf.xml

@@ -24,6 +24,11 @@
     <!--Colorize the Console -->
     <param name="colorize-console" value="true"/>
 
+    <!-- maximum number of simo db handles open -->
+    <param name="max-db-handles" value="50"/>
+    <!-- maximum number of seconds to wait for a new db handle before failing -->
+    <param name="db-handle-timeout" value="10"/>
+
     <!-- minimum idle CPU before refusing calls -->
     <!--<param name="min-idle-cpu" value="25"/>-->
 

src/include/private/switch_core_pvt.h

@@ -249,6 +249,8 @@ struct switch_runtime {
 	switch_dbtype_t odbc_dbtype;
 	char hostname[256];
 	int multiple_registrations;
+	uint32_t max_db_handles;
+	uint32_t db_handle_timeout;
 };
 
 extern struct switch_runtime runtime;

src/switch_core.c

@@ -1283,7 +1283,9 @@ SWITCH_DECLARE(switch_status_t) switch_core_init(switch_core_flag_t flags, switc
 	memset(&runtime, 0, sizeof(runtime));
 	gethostname(runtime.hostname, sizeof(runtime.hostname));
 
-
+	runtime.max_db_handles = 50;
+	runtime.db_handle_timeout = 5000000;;
+	
 	runtime.runlevel++;
 	runtime.sql_buffer_len = 1024 * 32;
 	runtime.max_sql_buffer_len = 1024 * 1024;
@@ -1550,6 +1552,23 @@ static void switch_load_core_config(const char *file)
 					if (tmp > -1 && tmp < 11) {
 						switch_core_session_ctl(SCSC_DEBUG_LEVEL, &tmp);
 					}
+				} else if (!strcasecmp(var, "max-db-handles")) {
+					long tmp = atol(val);
+
+					if (tmp > 4 && tmp < 5001) {
+						runtime.max_db_handles = (uint32_t) tmp;
+					} else {
+						switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "max-db-handles must be between 5 and 5000\n");
+					}
+				} else if (!strcasecmp(var, "db-handle-timeout")) {
+					long tmp = atol(val);
+					
+					if (tmp > 0 && tmp < 5001) {
+						runtime.db_handle_timeout = (uint32_t) tmp * 1000000;
+					} else {
+						switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "db-handle-timeout must be between 1 and 5000\n");
+					}
+					
 				} else if (!strcasecmp(var, "multiple-registrations")) {
 					runtime.multiple_registrations = switch_true(val);
 				} else if (!strcasecmp(var, "sql-buffer-len")) {

src/switch_core_sqldb.c

@@ -66,8 +66,8 @@ static struct {
 	switch_cache_db_handle_t *handle_pool;
 	switch_thread_cond_t *cond;
 	switch_mutex_t *cond_mutex;
-	int total_handles;
+	uint32_t total_handles;
-	int total_used_handles;
+	uint32_t total_used_handles;
 } sql_manager;
 
 
@@ -273,11 +273,29 @@ SWITCH_DECLARE(switch_status_t) _switch_cache_db_get_db_handle(switch_cache_db_h
 	char db_callsite_str[CACHE_DB_LEN] = "";
 	switch_cache_db_handle_t *new_dbh = NULL;
 	switch_ssize_t hlen = -1;
+	int waiting = 0;
+	uint32_t yield_len = 100000, total_yield = 0;
 
 	const char *db_name = NULL;
 	const char *db_user = NULL;
 	const char *db_pass = NULL;
 
+	while(runtime.max_db_handles && sql_manager.total_handles >= runtime.max_db_handles && sql_manager.total_used_handles >= sql_manager.total_handles) {
+		if (!waiting++) {
+			switch_log_printf(SWITCH_CHANNEL_ID_LOG, file, func, line, NULL, SWITCH_LOG_WARNING, "Max handles %u exceeded, blocking....\n", 
+							  runtime.max_db_handles);
+		}
+
+		switch_yield(yield_len);
+		total_yield += yield_len;
+		
+		if (runtime.db_handle_timeout && total_yield > runtime.db_handle_timeout) {
+			switch_log_printf(SWITCH_CHANNEL_ID_LOG, file, func, line, NULL, SWITCH_LOG_ERROR, "Error connecting\n");
+			*dbh = NULL;
+			return SWITCH_STATUS_FALSE;
+		}
+	}
+
 	switch (type) {
 	case SCDB_TYPE_ODBC:
 		{