Merge branch 'devel' of https://github.com/arangodb/arangodb into devel

arangod/Cluster/ClusterMethods.cpp

@@ -2382,6 +2382,8 @@ ClusterMethods::persistCollectionInAgency(
           }), dbServers.end());
     }
     std::random_shuffle(dbServers.begin(), dbServers.end());
+  } else {
+    dbServers = ci->getCurrentDBServers();
   }
 
   // cluster system replicationFactor is 1...allow startup with 1 DBServer.

arangod/VocBase/ManagedDocumentResult.cpp

@@ -80,7 +80,7 @@ void ManagedDocumentResult::setManaged(std::string&& str, TRI_voc_rid_t revision
 
 void ManagedDocumentResult::reset() noexcept {
   if(_managed) {
-    delete _vpack;
+    delete[] _vpack;
   }
   _managed = false;
   _length = 0;

lib/ApplicationFeatures/EnvironmentFeature.cpp

@@ -83,6 +83,22 @@ void EnvironmentFeature::prepare() {
   } catch (...) {
     // file not found or value not convertible into integer
   }
+  
+  try {
+    std::string value =
+        basics::FileUtils::slurp("/proc/sys/net/ipv4/tcp_tw_recycle");
+    uint64_t v = basics::StringUtils::uint64(value);
+    if (v != 0) {
+      LOG_TOPIC(WARN, Logger::COMMUNICATION)
+          << "/proc/sys/net/ipv4/tcp_tw_recycle is enabled (" << v << ")"
+          << "'. This can lead to all sorts of \"random\" network problems. "
+          << "It is advised to leave it disabled (should be kernel default)";
+      LOG_TOPIC(WARN, Logger::COMMUNICATION) << "execute 'sudo bash -c \"echo 0 > "
+                                         "/proc/sys/net/ipv4/tcp_tw_recycle\"'";
+    }
+  } catch (...) {
+    // file not found or value not convertible into integer
+  }
 
   try {
     std::string value =