diff --git a/lib/MySQL_Thread.cpp b/lib/MySQL_Thread.cpp
index 5cabfe05e..63f99e62a 100644
--- a/lib/MySQL_Thread.cpp
+++ b/lib/MySQL_Thread.cpp
@@ -2268,7 +2268,7 @@ __run_skip_1a:
 							mysess->thread=NULL;
 							// we first delete the association in sessmap
 							sessmap.erase(mysess->thread_session_id);
-							if (mysql_sessions->len-1 > 0) {
+							if (mysql_sessions->len) {
 								// take the last element and adjust the map
 								MySQL_Session *mysess_last=(MySQL_Session *)mysql_sessions->index(mysql_sessions->len-1);
 								sessmap[mysess_last->thread_session_id]=sess_pos;
@@ -2313,7 +2313,7 @@ __run_skip_1a:
 						mysess->thread=NULL;
 						// we first delete the association in sessmap
 						sessmap.erase(mysess->thread_session_id);
-						if (mysql_sessions->len-1 > 0) {
+						if (mysql_sessions->len) {
 						// take the last element and adjust the map
 						MySQL_Session *mysess_last=(MySQL_Session *)mysql_sessions->index(mysql_sessions->len-1);
 							sessmap[mysess_last->thread_session_id]=sess_pos;