@Override
  public void evictValue(Object key) {
    final LocalRegion owner = _getOwner();
    RegionEntry re = getEntry(key);
    if (re != null) {
      synchronized (re) {
        if (!re.isValueNull()) {
          re.setValueToNull();
          owner.getDiskRegion().incNumEntriesInVM(-1L);
          owner.getDiskRegion().incNumOverflowOnDisk(1L);
          if (owner instanceof BucketRegion) {
            ((BucketRegion) owner).incNumEntriesInVM(-1L);
            ((BucketRegion) owner).incNumOverflowOnDisk(1L);
          }
        }
      }
    }
  }
This code needs to be evaluated. It was added quickly to help PR persistence not to consume as
much memory.
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegionMap.java