[BUG] The sorting logic for the "slowest first" display in the skywalking-horizon-ui traces query function does not yield the expected results.

[Hwting]

HI，The sorting logic for the "slowest first" display in the skywalking-horizon-ui traces query function does not yield the expected results.

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OAP:10.4.0
skywalking-horizon-ui: main Build
db：banyandb

[wu-sheng]

I checked the codes and data. It seems not a bug (unfriendly though) but caused by the different behavior of v2 query. Right now, v2 query is based on segment's latency, but the response list carries trace latency. They two could have big different.
@hanahmily We still need to consider a latency field from complete trace perspective.

[hanahmily]

I'm going to propose a dedicated trace-level latency tag/column derived from the full trace duration (i.e., trace latency = max(span.end_time) - min(span.start_time)).
Similar to post-sampling, we can accumulate all spans/segments by trace_id, calculate the latency once the trace is assembled, and persist the result for storage and querying. Perhaps a new data file should be introduced to hold trace-specific tags/columns.