@Override
        public PackExtIndex extIndex(int packId) throws IOException {
            if (extIndices[packId] == null) {
                extIndices[packId] = column.extIndex(packId);
            }
            return extIndices[packId];
        }
Free the cache content before die.
indexr-segment/src/main/java/io/indexr/segment/storage/CachedSegment.java