[IMPALA-5539] Reading timestamps from Kudu are wrong with -use_local_tz_for_unix_ts

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 2.9.0
• Fix Version/s: Impala 2.10.0
• Component/s: Backend
• Labels: Kudu timestamp
• Epic Color: ghx-label-5
• Assignee: Matthew Jacobs
• Reporter: yyzzjj
• Created: 20/Jun/17 10:40
• Updated: 19/Jul/17 22:26
• Resolved: 19/Jul/17 22:26

Description

our impalad start with flag use_local_tz_for_unix_timestamp_conversions = true
so be timeconversion use local time zone

Frontend KuduUtil call utc_to_unix_micros function got time (not handle local time zone branch , time is not equal be time conversion TimestampValue::ToUnixTime)

// Some comments here
inline bool TimestampValue::UtcToUnixTime(time_t* unix_time) const {
  DCHECK(unix_time != nullptr);
  if (UNLIKELY(!HasDateAndTime())) return false;
  const boost::posix_time::ptime temp(date_, time_);
  tm temp_tm = boost::posix_time::to_tm(temp);
  // TODO: Conversion using libc is very expensive (IMPALA-5357); find an alternative.
    *unix_time = timegm(&temp_tm);
  return true;
}

beijing/china is UTC + 8， return wrong result