Fix for OPENDJ-1160 : Write operations to non-groups force groups to be rel...

Ludovic Poitou

01.59.2013 0bd15da0682c55a6f3e3da8535fc2ce891488961

Fix for OPENDJ-1160 : Write operations to non-groups force groups to be reloaded.
The refreshToken was updated on each add/mod/delete regardless of the type of entry, causing intensive contention on group membership evaluation.
Changes include reduction of the critical section as well as moving the update of refreshToken only when groups are modified.
CR-2400, thanks to the nice reviewers.

 opends/src/server/org/opends/server/core/GroupManager.java

@@ -124,7 +124,8 @@

  // A mapping between the DNs of all group entries and the corresponding
  // group instances.
  private DITCacheMap<Group> groupInstances;
  private DITCacheMap<Group>
      groupInstances;

  // Lock to protect internal data structures.
  private final ReentrantReadWriteLock lock;
@@ -767,16 +768,7 @@
        }
      }
    }
    lock.writeLock().lock();
    try
    {
      createAndRegisterGroup(entry);
      refreshToken++;
    }
    finally
    {
      lock.writeLock().unlock();
    }
    createAndRegisterGroup(entry);
  }


@@ -802,8 +794,10 @@
    lock.writeLock().lock();
    try
    {
      groupInstances.removeSubtree(entry.getDN(), null);
      refreshToken++;
      if (groupInstances.removeSubtree(entry.getDN(), null))
      {
        refreshToken++;
      }
    }
    finally
    {
@@ -834,6 +828,21 @@
      }
    }

    lock.readLock().lock();
    try
    {
      if (!groupInstances.containsKey(oldEntry.getDN()))
      {
        // If the modified entry is not in any group instance, it's probably
        // not a group, exit fast
        return;
      }
    }
    finally
    {
      lock.readLock().unlock();
    }

    lock.writeLock().lock();
    try
    {
@@ -845,7 +854,6 @@
          groupInstances.remove(oldEntry.getDN());
        }
        createAndRegisterGroup(newEntry);
        refreshToken++;
      }
    }
    finally
@@ -911,7 +919,10 @@
        group.setGroupDN(groupDN);
        groupInstances.put(groupDN, group);
      }
      refreshToken++;
      if (!groupSet.isEmpty())
      {
        refreshToken++;
      }
    }
    finally
    {
@@ -1078,6 +1089,7 @@
          try
          {
            groupInstances.put(entry.getDN(), groupInstance);
            refreshToken++;
          }
          finally
          {