void setDataOffset(int version, long dataOffset) {
            dpnOffset = dataOffset;
            indexOffset = dpnOffset + dpnSize;
            if (version < Version.VERSION_6_ID) {
                packOffset = indexOffset + indexSize;
            } else {
                extIndexOffset = indexOffset + indexSize;
                packOffset = extIndexOffset + extIndexSize;
            }
        }
Store segment column by column.

<pre>
Segment storage structure:
|  IXRSEGxx | sementMeta | column0 | column1 ... | outerIndex0 | outerIndex0 ... |
            | <---                      sectionSize                        ----> |

Column structure:
|  dpn | rsIndex | extIndex | dataPack |
</pre>
indexr-segment/src/main/java/io/indexr/segment/storage/itg/IntegrateV1.java