untuple expand fields can not be accessed again

[melin]

untuple expand fields can not be accessed again

select ACTIVITY_RAW, parseDateTime64BestEffort(toString(S_D_EVENTOCCURTIME)) from (
  SELECT JSONExtractRaw(activity_json, 'activity') as ACTIVITY_RAW,
    untuple(JSONExtract(ACTIVITY_RAW, 'Tuple(S_S_PARTNERCODE String, S_S_EVENTTYPE String, S_S_EVENTID String, 
    S_E_INVOKETYPE String, S_D_EVENTOCCURTIME Int64')) activity
  FROM activity_result
);

[hexiaoting]

Can you give us a minimal info that can reproduce this error? including how to create this table and some data

[melin]

Can you give us a minimal info that can reproduce this error? including how to create this table and some data

select _ut_1 from (select untuple(tuple(1, 2)))

error: Code: 8, e.displayText() = DB::Exception: Cannot find column _ut_1 in source stream (version 20.12.3.3 (official build))

[alexey-milovidov]

CC @amosbird @KochetovNicolai

[larry-cdn77]

I can indeed see this in version 21.8 LTS (was fine in previous 21.3 LTS)

[alexey-milovidov]

The behavior of untuple function has been deliberately made worse as the previous implementation was not memory-safe.
The initial implementation did not pass ClickHouse testing with fuzzing.
Now it's only possible to access them with the following syntax:

SELECT `tupleElement((1, 2), 1)` FROM (select untuple(tuple(1, 2)))

It is inconvenient. But I'd rather recommend not using the untuple function at all.