Robbie Zhang created IMPALA-8108: ------------------------------------ Summary: Impala query returns TIMESTAMP values in different types Key: IMPALA-8108 URL: https://issues.apache.org/jira/browse/IMPALA-8108 Project: IMPALA Issue Type: Improvement Components: Backend Reporter: Robbie Zhang
When a timestamp has a .000 or .000000 or .000000000 (when fraction value is zeros) the timestamp is displayed with no fraction of second. For example: {code:java} select cast(ts as timestamp) from (values ('2019-01-11 10:40:18' as ts), ('2019-01-11 10:40:19.0'), ('2019-01-11 10:40:19.00'), ('2019-01-11 10:40:19.000'), ('2019-01-11 10:40:19.0000'), ('2019-01-11 10:40:19.00000'), ('2019-01-11 10:40:19.000000'), ('2019-01-11 10:40:19.0000000'), ('2019-01-11 10:40:19.00000000'), ('2019-01-11 10:40:19.000000000'), ('2019-01-11 10:40:19.000000001') ) t;{code} The output is: {code:java} +-------------------------------+ |cast(ts as timestamp)| +-------------------------------+ |2019-01-11 10:40:18| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19| |2019-01-11 10:40:19.000000001| +-------------------------------+ {code} As we can see, values of the same column are returned in two different types. The inconsistency breaks some downstream use cases. The reason is that impala uses function boost::posix_time::to_simple_string(time_duration) to convert timestamp to a string and to_simple_string() remove fractional seconds if they are all zeros. Perhaps we can append ".000000000" if the length of the string is 8 (HH:MM:SS). For now we can work around it by using function from_timestamp(ts, 'yyyy-mm-dd hh:mm.ss.sssssssss') to unify the output (convert to string), or using function millisecond(ts) to get fractional seconds. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org