Optimize the read performance of AGG and UNIQUE table with too much versions #4957
Description
When there are many versions of a table, we have a lot of time spent on sorting and merging rowset
In our scenario, this sorting is actually a merge sorting of multiple ordered queues, and usually due to the existence of compaction, we will have a relatively large base rowset and several small rowset, so we can combine The small rowset is sorted first and merged with the large rowset to optimize the read performance