public void setOldValueForQueryProcessing() {
    RegionEntry reentry = getRegion().getRegionMap().getEntry(getKey());
    if (reentry != null) {
      @Retained
      Object v = reentry.getValueOffHeapOrDiskWithoutFaultIn(getRegion());
      if (!(v instanceof Token)) {
        // v has already been retained.
        basicSetOldValue(v);
        // this event now owns the retention of v.
      }
    }
  }
establish the old value in this event as the current cache value, whether in memory or on disk
geode-core/src/main/java/org/apache/geode/internal/cache/EntryEventImpl.java