The world regions and their time zone names comply with the IANA specification for world regions and associated time zone names.

For more information about the IANA specifications, see http://www.iana.org/time-zones.

Time zones are subject to change. You can download the latest IANA time zone definitions during installation (or after installation using the iisuitz utility, described in the Command Reference Guide).

Ingres region and time zone names available in previous releases can be specified, but now link to the equivalent IANA time zone name. This allows older installations configured with Ingres time zone names to connect to installations where IANA time zones are used.

Ingres installations using IANA time zones that connect to older installations must be configured to use an Ingres time zone name to maintain compatibility with the older Ingres installation.

A new installation is always configured with an IANA time zone name. If, for either of the reasons described above, an Ingres time zone name is required for a new installation, then you must set II_TIMEZONE_NAME after installation using the ingsetenv utility.

When upgrading an existing installation to Ingres 11, the current Ingres time zone name will be maintained, which will avoid the two Ingres Net peer-to-peer scenarios described above.

"Custom" Ingres time zone names are no longer supported. In this case, upgrades will request that you set an IANA time zone name.

IANA fixed GMT offset time zone names, which are POSIX compliant, are offset in the opposite direction to the old Ingres fixed offset GMT time zone names. For example, IANA's Etc-GMT+4 refers to a GMT offset 4 hours west of GMT and is equivalent to the Ingres time zone name GMT-4. IANA's Etc-GMT-4 is 4 hours east of GMT and is equivalent to the Ingres time zone name GMT4.

If selecting an IANA fixed GMT offset time zone, you must consider this difference in GMT offset representation. If you continue to use an Ingres fixed GMT offset time zone name, Ingres will automatically map to the correct IANA fixed GMT offset time zone.