private void extend() throws PersistitException {
final long maximumPages = _volume.getSpecification().getMaximumPages();
final long extensionPages = _volume.getSpecification().getExtensionPages();
if (_extendedPageCount >= maximumPages || extensionPages <= 0) {
throw new VolumeFullException(this + " is full: " + _extendedPageCount + " pages");
}
// Do not extend past maximum pages
final long pageCount = Math.min(_extendedPageCount + extensionPages, maximumPages);
resize(pageCount);
}