Traceback (most recent call last):
  File "/usr/sbin/update-apt-xapian-index", line 108, in <module>
    indexer.rebuild(opts.pkgfile)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 730, in rebuild
    self.buildIndex(dbdir, generator)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 693, in buildIndex
    db = xapian.WritableDatabase(pathname, xapian.DB_CREATE_OR_OVERWRITE)
  File "/usr/lib/python2.7/dist-packages/xapian/__init__.py", line 4009, in __init__
    _xapian.WritableDatabase_swiginit(self,_xapian.new_WritableDatabase(*args))
DatabaseLockError: Unable to get write lock on /var/cache/apt-xapian-index/index.1: Couldn't fork: Cannot allocate memory