TZRULE=NONE

TZRULE enables BMC AMI Recover to adjust day and time values when you run the product after a DST change, but scan log records that are from a period before the time change, which is called scanning across a DST boundary.

The default value, NONE, indicates that your locale does not observe DST or that you do not want the product to make adjustments for DST. To enable DST adjustment, you must define day and time values as a character string in the following format:

The first date (startDayRule) describes when the change to DST occurs, and the second date (endDayRule) describes when the change back happens. The time is optional and defaults to 02:00:00 (the default conversion time).

Use one of the following formats forstartDayRule andendDayRule:

• Mm.n.d

  This is the standard format for most countries. Using this format, specify the month, week, and day of the week on which DST begins and ends, as follows:

  • The variable m represents the month; valid values are 1 through 12 (January through December).
  • The variable n represents the week of the month in which the day d occurs; valid values are 1 through 5. Week 1 is the first week in which day d occurs, and week 5 specifies the last d day in the month.
  • The variable d represents the day; valid values are 0 through 6 (Sunday through Saturday).

  In the following example, DST begins on the second Sunday of March at 2:00 a.m., and ends on the first Sunday of November at 2:00 a.m.:

  TZRULE=M3.2.0/2:00:00,M11.1.0/2:00:00

  The following example, which uses the default conversion time of 2:00 a.m and omits the time specification, is also valid:

  TZRULE=M3.2.0,M11.1.0

• Jn

  Specify the Julian day n, where n is a value from 1 through 365. This format does not account for leap days; that is, in all years, including leap years, February 28 is day 59 and March 1 is day 60. You cannot explicitly refer to February 29.

  In the following example, DST begins on April 1 at 12:34:56 p.m., and ends on November 1 at 2:34:56 a.m.:

  TZRULE=J91/12:34:56,J305/2:34:56

• n

  Specify the zero-based Julian day n, where n is a value from 0 through 365. In this format, leap days are counted, and you can refer to February 29.

  In the following example, DST begins on April 1 (leap years), or April 2 (nonleap years) at 12:34:56 p.m., and ends on November 1 at 2:34:56 a.m.:

  TZRULE=91/12:34:56,305/2:34:56

Considerations for DST adjustment

To understand DST adjustment, remember that BMC AMI Recover uses the operating system to translate date and time values into the operating system’s store clock format. The operating system uses an offset based on your time zone to translate the values. For example: assume that you are in the northern hemisphere, you run BMC AMI Recover in May (after the change to DST), and you define a scan range from 15:00 to 16:00 on February 14 (before the time change).

• If you set TZRULE to enable adjustment, the product knows that the time zone offset in May is different than the time zone offset that was used when Db2 wrote the log records in February (the difference is one hour). The product adjusts for this difference, selects log records from 15:00 to 16:00 on February 14, and prints the time values of those records in reports starting with 15:nn.
• If you do not set TZRULE to enable adjustment, the product uses the time zone offset for May. Because the offset was different in February, the product selects log records from 14:00 to 15:00 on February 14, and prints the time value of those log records in reports starting with 15:nn. The discrepancy in the time zone offset creates a discrepancy between the log records that you request and the log records that the product provides in output.

Be aware of the following additional points regarding DST adjustment and the TZRULE installation option:

• BMC AMI Recover provides adjustment because the operating system does not account for changes in the time zone offset that have occurred in the past. The operating system always uses the current time zone offset when it converts a date and time value into store clock format.
• By default, adjustment is not enabled. To enable it, set the TZRULE installation option value.
• The options migration feature of the Installation System cannot carry over DST installation option values from a previous release of the product. You must provide a value for TZRULE if you want to enable DST adjustment.
• Adjustment affects only how the product handles the standard timestamp values that Db2 stores in all log records (using the operating system’s store clock format).