Csaba Ringhofer 41f0c6a5a6 IMPALA-5664: Unix time to timestamp conversions may crash Impala ...

TimestampValue::FromSubsecondUnixTime() and UtcFromUnixTimeMicros()
are incorrect only in case of the last second of 1399, because these
sub-second values are rounded first towards 1400-01-01 00:00:00, which
is accepted as a valid date, and the sub-second part is subtracted
afterwards, leading to a date outside the valid interval. The maximum
case, 9999-12-31 59:59:59 is a bit different, because as I understand,
with nanosecond precision posix times, the maximum value is actually
10000-01-01. 00:00:00 minus 1 nanosec.

TimestampValue::FromUnixTimeNanos() can create problematic TimestampValues
both <1400 and 10000<=.

These timestamps can cause problems, because most code assumes that if
HasDate/HasTime is true, then it really is a valid timestamp.

To fix this, the posix times are checked in the constructor of
TimestampValue, and if it is outside the valid interval,both time_
and date_ are set to not_a_date_time.

Test:
select cast(-17987443200-0.1 as timestamp);
This query no longer crashes, but returns NULL, similarly to other
< 1400 timestamps.

Change-Id: I77b2f6284d3a597f57e61c17a67c959eff9e38ff
Reviewed-on: http://gerrit.cloudera.org:8080/7954
Reviewed-by: Lars Volker <lv@cloudera.com>
Tested-by: Impala Public Jenkins

2017-10-21 03:13:14 +00:00

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