diff --git a/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-sessions/jetty-ee10-test-sessions-mongodb/src/test/java/org/eclipse/jetty/ee10/session/nosql/mongodb/MongoSessionDataStoreTest.java b/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-sessions/jetty-ee10-test-sessions-mongodb/src/test/java/org/eclipse/jetty/ee10/session/nosql/mongodb/MongoSessionDataStoreTest.java
index 0bccf09cdd5..9bc5efe2df3 100644
--- a/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-sessions/jetty-ee10-test-sessions-mongodb/src/test/java/org/eclipse/jetty/ee10/session/nosql/mongodb/MongoSessionDataStoreTest.java
+++ b/jetty-ee10/jetty-ee10-tests/jetty-ee10-test-sessions/jetty-ee10-test-sessions-mongodb/src/test/java/org/eclipse/jetty/ee10/session/nosql/mongodb/MongoSessionDataStoreTest.java
@@ -164,7 +164,7 @@ public void testGoodWorkerName() throws Exception
     {
         Server server = new Server();
         DefaultSessionIdManager idMgr = new DefaultSessionIdManager(server);
-        idMgr.setWorkerName("NODE99");
+        idMgr.setWorkerName("NODE_99");
         server.addBean(idMgr);
 
         //create the SessionDataStore
diff --git a/jetty-integrations/jetty-nosql/src/main/java/org/eclipse/jetty/nosql/mongodb/MongoSessionDataStore.java b/jetty-integrations/jetty-nosql/src/main/java/org/eclipse/jetty/nosql/mongodb/MongoSessionDataStore.java
index 7c66429a9a2..041658dde8c 100644
--- a/jetty-integrations/jetty-nosql/src/main/java/org/eclipse/jetty/nosql/mongodb/MongoSessionDataStore.java
+++ b/jetty-integrations/jetty-nosql/src/main/java/org/eclipse/jetty/nosql/mongodb/MongoSessionDataStore.java
@@ -157,7 +157,7 @@ public class MongoSessionDataStore extends NoSqlSessionDataStore
      */
     private DBObject _version1;
 
-    private final Pattern _workerNamePattern = Pattern.compile("[0-9a-zA-Z]*");
+    private static final Pattern _workerNamePattern = Pattern.compile("[_0-9a-zA-Z]*");
 
     /**
      * Access to MongoDB