From d46160f68b2fbb36ddecba12c6e620946366b97c Mon Sep 17 00:00:00 2001
From: Felix Schumacher <felix.schumacher@internetallee.de>
Date: Wed, 14 Mar 2018 14:02:11 +0100
Subject: [PATCH 5/5] Load, validate and reactivate stored sessions only once.

---
 .../catalina/session/PersistentManagerBase.java    | 31 ++++++++++++++--------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/java/org/apache/catalina/session/PersistentManagerBase.java b/java/org/apache/catalina/session/PersistentManagerBase.java
index 9397192..e2f1ee5 100644
--- a/java/org/apache/catalina/session/PersistentManagerBase.java
+++ b/java/org/apache/catalina/session/PersistentManagerBase.java
@@ -183,6 +183,8 @@ public abstract class PersistentManagerBase extends ManagerBase
      */
     private final Map<String,Object> sessionSwapInLocks = new HashMap<>();
 
+    private final ThreadLocal<Session> sessionToSwapIn = new ThreadLocal<>();
+
 
     // ------------------------------------------------------------- Properties
 
@@ -707,18 +709,25 @@ public abstract class PersistentManagerBase extends ManagerBase
             session = sessions.get(id);
 
             if (session == null) {
-                session = loadSessionFromStore(id);
-
-                if (session != null && !session.isValid()) {
-                    log.error(sm.getString(
-                            "persistentManager.swapInInvalid", id));
-                    session.expire();
-                    removeSession(id);
-                    session = null;
-                }
+                Session currentSwapInSession = sessionToSwapIn.get();
+                try {
+                    if (currentSwapInSession == null || !id.equals(currentSwapInSession.getId())) {
+                        session = loadSessionFromStore(id);
+                        sessionToSwapIn.set(session);
+
+                        if (session != null && !session.isValid()) {
+                            log.error(sm.getString("persistentManager.swapInInvalid", id));
+                            session.expire();
+                            removeSession(id);
+                            session = null;
+                        }
 
-                if (session != null) {
-                    reactivateLoadedSession(id, session);
+                        if (session != null) {
+                            reactivateLoadedSession(id, session);
+                        }
+                    }
+                } finally {
+                    sessionToSwapIn.remove();
                 }
             }
         }
-- 
2.7.4