They can have the same value, but not always. The query_review table keeps
unique instances of each query, but the query_review_history can have
multiple entries for each query fingerprint. The fields ts_min and ts_max
are the statistics aggregated for that query in that particular duration of
time. I'm not sure what the original author intended with the abbreviation
ts_, but I think of it as "time slice" or "time series."
In the query_review table, there's only one entry per unique query
fingerprint, and the values for first_seen and last_seen are updated with
the smallest value of ts_min for any record in the history table, and
last_seen has the highest value of any ts_max value.