[
https://issues.apache.org/jira/browse/IMPALA-5563?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Attila Jeges closed IMPALA-5563.
--------------------------------
> Timezone lookup may be ambiguous
> --------------------------------
>
> Key: IMPALA-5563
> URL: https://issues.apache.org/jira/browse/IMPALA-5563
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 2.0
> Reporter: Matthew Jacobs
> Assignee: Attila Jeges
> Priority: Major
> Labels: timezone
> Fix For: Impala 3.1.0
>
>
> When using functions like {{to_utc_timestamp}} that take a string timezone
> parameter, if the timezone is not a 'region specifier' [1] (i.e. a key into
> the timezone database entries), then Impala attempts to match the string
> parameter against a number of other properties of the timezones in the
> database [2]:
> * a zone's std abbreviation
> * a zone's std full name
> * a zone's dst abbreviation
> * a zone's dst full name
> {code}
> time_zone_ptr TimezoneDatabase::FindTimezone(
> const string& tz, const TimestampValue& tv, bool tv_in_utc) {
> ...
> // See if they specified a zone id
> time_zone_ptr tzp = tz_database_.time_zone_from_region(tz);
> if (tzp != NULL) return tzp;
> for (vector<string>::const_iterator iter = tz_region_list_.begin();
> iter != tz_region_list_.end(); ++iter) {
> time_zone_ptr tzp = tz_database_.time_zone_from_region(*iter);
> DCHECK(tzp != NULL);
> if (tzp->dst_zone_abbrev() == tz) return tzp;
> if (tzp->std_zone_abbrev() == tz) return tzp;
> if (tzp->dst_zone_name() == tz) return tzp;
> if (tzp->std_zone_name() == tz) return tzp;
> }
> return time_zone_ptr();
> }
> {code}
> This can result in ambiguous zones being used because the properties listed
> above are not unique, e.g.
> {code}
> mj@mj-desktop:~/dev/Impala$ grep CEST be/src/exprs/timezone_db.cc
> \"Africa/Ceuta\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Antarctica/Troll\",\"UTC\",\"Coordinated Universal
> Time\",\"CEST\",\"Central European Summer
> Time\",\"+00:00:00\",\"+02:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Arctic/Longyearbyen\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Atlantic/Jan_Mayen\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"CET\",\"CET\",\"Central European Time\",\"CEST\",\"Central European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+02:00:00\",\"-1;0;10\",\"+02:00:00\"\n\
> \"ECT\",\"CET\",\"Central European Time\",\"CEST\",\"Central European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Amsterdam\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Andorra\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Belgrade\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Berlin\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Bratislava\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Brussels\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Budapest\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Busingen\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Copenhagen\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Gibraltar\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Ljubljana\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Luxembourg\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Madrid\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Malta\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Monaco\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Oslo\",\"CET\",\"Central European Time\",\"CEST\",\"Central European
> Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Paris\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Podgorica\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Prague\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Rome\",\"CET\",\"Central European Time\",\"CEST\",\"Central European
> Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/San_Marino\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Sarajevo\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Skopje\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Stockholm\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Tirane\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Vaduz\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Vatican\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Vienna\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Warsaw\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Zagreb\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Europe/Zurich\",\"CET\",\"Central European Time\",\"CEST\",\"Central
> European Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> \"Poland\",\"CET\",\"Central European Time\",\"CEST\",\"Central European
> Summer
> Time\",\"+01:00:00\",\"+01:00:00\",\"-1;0;3\",\"+01:00:00\",\"-1;0;10\",\"+01:00:00\"\n\
> {code}
> Based on the code, CEST may match a zone with many different GMT offsets or
> DST adjustments/dates. Depending on the order in which the list of zones
> happens to be iterated, the results will be different.
> 1: http://www.boost.org/doc/libs/1_64_0/doc/html/date_time/local_time.html
> 2:
> https://github.com/apache/incubator-impala/blob/2.9.0/be/src/exprs/timezone_db.cc#L45
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