Always use iso format and test timezone impact - #75
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serprex
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Aug 28, 2026
I noticed that timestamptz values weren't exported with time zone information, which is necessary to ensure proper round-tripping. Add the `date_time_output_format='iso'` setting to each chDB query to always format `timestamp` and `timestamptz` values in plain text formats with the ISO-8601 format in UTC. Remove setting the `datestyle` and `timezone` GUCs to hard-coded constants, instead allowing them to be respected. Or at least, we respect the `timezone` GUC for converting `timestamp` values, but always emit UTC for both timestamp and timestamptz, since that's all that `date_time_output_format='iso'` supports. Add a new test file, `test/sql/timestamp.sql` to test the impact of the new setting on plain-text output, as well as the impact of the `timezone` setting on `timestamp` values. Interestingly, setting a time zone in the structure, e.g. `DateTime64(3, 'Japan')`, has no impact on exported values. Add the "Timestamp Conversion" section to the chdb_hook docs to document these behaviors. In passing, change the `real` columns in `test/qa/taxi.sql` to `double precision`, since the source defines the values as `Float64`.
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I noticed that timestamptz values weren't exported with time zone information, which is necessary to ensure proper round-tripping.
Add the
date_time_output_format='iso'setting to each chDB query to always formattimestampandtimestamptzvalues in plain text formats with the ISO-8601 format in UTC.Remove setting the
datestyleandtimezoneGUCs to hard-coded constants, instead allowing them to be respected. Or at least, we respect thetimezoneGUC for convertingtimestampvalues, but always emit UTC for both timestamp and timestamptz, since that's all thatdate_time_output_format='iso'supports.Add a new test file,
test/sql/timestamp.sqlto test the impact of the new setting on plain-text output, as well as the impact of thetimezonesetting ontimestampvalues. Interestingly, setting a time zone in the structure, e.g.DateTime64(3, 'Japan'), has no impact on exported values.Add the "Timestamp Conversion" section to the chdb_hook docs to document these behaviors.
In passing, change the
realcolumns intest/qa/taxi.sqltodouble precision, since the source defines the values asFloat64.