When compaction case, memory map offsets coming to same olap convertor which is from 0 to 0+size
but it should be continue in different pages when in one segment writer .
eg :
last block with map offset : [3, 6, 8, ... 100]
this block with map offset : [5, 10, 15 ..., 100]
the same convertor should record last offset to make later coming offset followed last offset.
so after convertor :
the current offset should [105, 110, 115, ... 200], then column writer just call append_data() to make the right offset data append pages