Managing Time Zone related issues in Moxie Email.

This article describes the changes made in Channels 9.4 CU8 QFE 1 to manage issues related to email and System Response Service Level (SRSL) resulting from time-changes in the various time zones.

Data for SRSL Calculation

For calculating email SRSL correctly, the table “WorldTimeZone” in Channels Database needs to be updated as described in this section.

The “WorldTimeZone” table:

• Has data for calculating DLS (day light savings) time and STD (standard) time for a time zone.
• Is populated by SQL scripts during product installation.

The stored procedure “sproc_UpdateDLSnSTDdates”:

• Calculates the DLS and STD time using configuration data in the table “WorldTimeZone”.
• It is called when Channels Server starts-up.
• It is scheduled as a server task executed on the 1^st of January every year.

The table “SchedulingProfiles”:

• Has the scheduling profiles configured in Channels Administrator > System > Schedule Maker.
  Channels Server fetches the configured time from this table and checks against the current time by adding one of the following based on the configured time zone to check if it matches the configured time:
  • STD offset (Transition_1_Offset)
  • DLS offset (Transition_2_Offset)

The STD offset field should have the value of the standard offset when the country is in standard time.

Transition Offsets

Transition offsets must be applied for time zones that are impacted by day light savings when the time transitions occur during the year. Channels database includes two transition offsets for this purpose.

• Transition_1_Offset
• Transition_2_Offset

“Transition_1_Offset” is applicable for the first transition for Australian time zones, which occurs in January. For example:

• When Australia/Melbourne (AEST/AEDT) deploys DST in January, the "Transition_1_Offset" is the  DST offset: +11 hours or 39600 seconds.
• During this time America/California (PST/PDT) deploys STD (standard time) hence the "Transition_1_Offset" is the same as STD offset:  -8 hours or -18800 seconds.

“Transition_2_Offset” is applicable for the second transition. Australian time zones end DST and move to STD in April and American time zones end STD and move to DST in the 2nd week of March.

• When Australia/Melbourne ends DST and transitions to STD, “Transition_2_Offset” is the STD offset:  +10 hours or 36000 seconds.
• When America/California ends DST and transitions to STD, “Transition_2_Offset” is the STD offset:  -7 hours or -25200 seconds.

If the offset values do not match the calculated values, they need to be corrected in the table “WorldTimeZone”.

Algorithm for Email expiry calculation

The algorithm for calculation of email expiry time based on SRSL has changed starting from Channels 9.4 CU8 QFE1. The calculation of expiry time uses the following logic:

• For countries in the northern hemisphere:
  •  STD (standard time) is calculated based on STD offset.
  •  DST is calculated based on "Transition_2_Offset" in the table "WorldTimeZone". 
• For countries in the southern hemisphere”
  • STD time is based on STD offset.
  • DST offset is based on "Transition_1_Offset" in the “WorldTimeZone” table.

The calculation of SRSL expiry time by the updated method is applicable to:

• Emails received into Channels systems post upgrade to 9.4 CU8 QFE 1.
• Transfer of emails from one mailbox to another.
• Rejecting emails from EAW panel.
• Rejecting emails from outbox.