public static boolean isRelevant(IColumn column, IColumnContainer container, int gcBefore) {
// the column itself must be not gc-able (it is live, or a still relevant tombstone, or has live
// subcolumns), (1)
// and if its container is deleted, the column must be changed more recently than the container
// tombstone (2)
// (since otherwise, the only thing repair cares about is the container tombstone)
long maxChange = column.mostRecentNonGCableChangeAt(gcBefore);
return (column.getLocalDeletionTime() >= gcBefore
|| maxChange > column.getMarkedForDeleteAt()) // (1)
&& (!container.isMarkedForDelete() || maxChange > container.getMarkedForDeleteAt()); // (2)
}
