Daylight Savings Timezone on HP

Michael Ashton (ashtonmd@bellsouth.net) wrote:
: I'll worry about Y2K later (I think OpenIngres handles it with a new
: logical).

: My immediate problem is a quirk in 6.4/04 on HP/UX with the change from
: Daylight to Standard Time and vice versa.  I didn't have a problem with
: this on VAX/VMS but it seems to be a problem on HP/UX.  Has anyone else
: had this problem and/or know of a solution?  It looks like the former
: "owners" here modfied the TZ info on one of the nodes but it's a problem
: on all 3 of my systems.  Thanks.

From: droesler@hpuscsc1.msr.hp.com (Dennis Roesler)

Make sure that the correct Timezone kernel parameter is set properly
for your timezone.  It's given in minutes from GMT.
The dbms will use that on the back end instead of the TZ variable in
your environment.  I'm not sure if it's in all cases, but enough that
you want to make sure the kernel Timezone parameter is correct.
I believe that the default is 480 (assumes PST or 8 hours from GMT.)

Dennis



From: "Michael D. Zorn" 

> My immediate problem is a quirk in 6.4/04 on HP/UX with the change from 
> Daylight to Standard Time and vice versa.  I didn't have a problem with 
> this on VAX/VMS but it seems to be a problem on HP/UX.  Has anyone else 
> had this problem and/or know of a solution?  It looks like the former 

   It's been a problem for us since the beginning.  (We're now at
OpenIngres 1.1/04.)  There are a lot of gory details that others can
fill you in on, but the problem seems to center around Ingres and HP-UX
dealing with Savings Time differently.  We had time-stamped data entered
from 6.3 (which didn't seem to deal with DST at all), then when we went
to 6.4 we found that a lot of our data was one hour off - all the data
during DST.  Our "workaround" (which really has no ill effects for us)
was to turn off DST for HP-UX.

  Evidently, date data is stored internally as an offset nr-of-seconds
since the beginning of the modern era (probably in GMT), and then Unix
routines are called to see how to convert the date for your present time
zone and type.  We even tried unloading everything out with the -c
option (everything ASCII), but that didn't help.

  So we just sit with TZ=PST8, and try to remember twice a year to reset
the system time (speaking of which, this next Sunday is Switchover time
(which means we go into Daylight Wasting Time?)).

  Our solution lacks a certain elegance, but it works.

Mike Zorn
Rockwell, Anaheim
zorn@dms-1.ri-dms.anatcp.rockwell.com
Ingres Q & A
To William's Home Page
Email William