[Openroad-users] eClient &Timezones-CORRECTION KB415539not KB415439

Fri Apr 11 17:49:36 EST 2008

Hi Bodo,

The nature of our application is if an employee is scheduled to start work
at a specific time then that is the time - it does not change depending on
which timezone you are viewing the data from.   I am rostered to start a
shift at 7:00 and finish at 15:00, then these times are static.   If this is
in Perth and I view the data in Sydney then I still want to see that the
employee is rostered to start at 7:00 and finish at 15:00 - not for the
times to alter.

What compounds this is that many employees using electronic timeclocks to
record their start and finish times and these is gathered by the OpenROAD
server and loaded - bypassing the local client.  They arrive unaltered so
the if the employee started in Perth as 6:42 then that is how it needs to be
recognised so it will correctly match to the start time of their shift - the
OpenROAD server in Sydney needs to know the Perth 07:00 shift start time is,
in fact, 07:00.

It is this nature of the application that makes it very different to a
scheduling tool where you want the Web conference to reflect different times
based on the local timezone.

So yes, in hindsight with these learnings, storing them in a varchar column
would have been potentially a better way to go (although we would have lost
access to the neat date handling functions we currently utilise).
Unfortunately much of the system is built around the Ingres Date usage and
date functions provided by Ingres and OpenROAD, and the time to convert the
system to use Varchar columns is significant, and then the upgrade of the
application to the client base makes this commercially not viable.

So, back to the approach of running the clients and the servers on the same
timezone. 

If Date ('now') gives the system date on the PC rather than the timezone
adjusted view of the current time then this will be perfect, however a
previous e-mail of yours indicates date('now') applies the II_Timezone_Name
applied during application startup  - so would that give the current time in
Sydney regardless of the location of the client if all clients were set to
the same timezone as the server?   IF so, back to the win32 SDK because we
would have all clients on the same timezone as the server.

Darren's original timezone question was interestingly different because we
need to adjust the times on the clocks accordingly, as we experience
daylight savings changes to times between states,.   We know the timzone
each clock resides in, we just need to know what time to set them to when
they are due to change, or if a user simply wants to reset the clock time.
The system controls this centrally so we need to process the clocks in
'timezone groups' - but how do we know what time to set them to?  We have a
group of clocks in Perth, a group in Adelaide, a group in Melbourne, and
another group in Brisbane - all in different timezones .  You provided a
solution where we could, as we process each group,  SET the II_Timezone
variable through another application / image, and return to the calling up
so the times can be processed based on the newly set timezone, repeating
this for each timezone.  This appears to be an excellent solution to our
problem and we will be implementing this.

Durwin's neat enhancement thought, however,  would be sensational, having
the facility to request a date time for a timezone, either passing no date
and a timezone (DATE(ingresdatevalue, ii_timezone_name) to return the
current date time for the timezone) - OR--  passing a datetime in the
current timezone and it is returned adjusted to the timezone passed into the
function.   This would address many issues with a simple coding construct, I
expect, but way beyond our technical capabilities!

Anyway - thank you all for your contributions.   we certainly understand
much, much more about date handling and the implication of various scenarios
on our solution.    Through these discussions we benefit greatly - just hope
others have not been too bored along the way!

Regards

Darren Mason

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Bodo Bergmann
Sent: Friday, 11 April 2008 4:42 PM
To: International OpenROAD Users
Subject: Re: [Openroad-users] eClient &Timezones-CORRECTION KB415539not
KB415439

Darren,

You wrote:

If a Sydney user then access the Perth times, the 9:00am will then be
displayed as 11:00am because it is applying the Sydney - NSW timezone.  The
reverse is true if a user in Perth needed to view times from a Sydney
employee.    11:00 am will be displayed as 9:00am.

We fear needing to introduce text fields to store the times that need to be
displayed on each screen

I think the handling is what most users that use timezone-aware software
would expect - e.g. if I plan a Web conference

for a distinct time (e.g. 4pm) in Germany I want the other attendees take
part in it at the correct time, not at 4pm of their local time.

Does this mean that you do not want to have any timezone specific handling
at all?

All your clients in all timezones would see the same date/time for dates
entered by any client.

Then why don't you just pass the dates as VARCHAR from the clients and store
them into a VARCHAR column?

Anyway, for the "remaining SELECT DATE('now') problem" you described:

You just have to pass the client's DATE('now') as a parameter to the
OpenROAD server,

which then uses it rather then selecting it from the DB

(e.g. by setting a global variable first, so you don't have to pass it along
procedures and methods).

Comments to Durwin: 

DATE LITERALS and Timezones

You can actually pass a timezone aware date literal between the client and
OpenROAD Server, e.g.

by using the date_gmt() function rather than simpe varchar() conversion.

DATE(ingresdatevalue, ii_timezone_name)

I had already provided a solution for the problem in a former email thread
"Timezone Question"

(which was also started by Darren Harvey). This solution can be applied on
both client and server.

Bodo.

Bodo Bergmann

Senior Software Engineer

OpenROAD Worldwide Development

Ingres Corp.

  _____  

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Durwin Wright
Sent: Friday, April 11, 2008 3:03 AM
To: International OpenROAD Users
Subject: Re: [Openroad-users] eClient &Timezones-CORRECTION KB415539not
KB415439

Hello Chris,

Good point Chris.  I have a question.  Are you talking about an INGRES DATE
or an INGRES DATE LITERAL.  Darren wants the value in Perth and Sydney to
have the same display value.

I believe what Darren actually wants is some like DATE(ingresdatevalue,
ii_timezone_name).  Alas, this does not exist.  It would be a pretty cool
enhancement!

Durwin Wright | Sr. Architect |  <blocked::mailto:Durwin.Wright at ingres.com>
Durwin.Wright at ingres.com | Ingres |
<blocked::http://maps.google.com/maps?q=500+arguello+street,+94063&ll=37.487
297,-122.233200&spn=0.004602,0.012771&t=k&hl=en> 500 Arguello Street | Suite
200 | Redwood City | CA | 94063 | USA  +1 650-587-5523 | fax: +1
650-587-5550 

  _____  

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Chris Wallace
Sent: Thursday, April 10, 2008 5:58 PM
To: International OpenROAD Users
Subject: Re: [Openroad-users] eClient & Timezones-CORRECTION KB415539not
KB415439

Darren,

Storing a 'local' view of the time is only good if you don't care / aren't
impacted by daylight savings changes.  Particularly, since Perth, Tassie and
Sydney/Melbourne are all change to or from daylight savings on different
dates.

Regards 
Chris Wallace

  _____  

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Darren Mason
Sent: Friday, 11 April 2008 07:39
To: 'International OpenROAD Users'
Subject: Re: [Openroad-users] eClient & Timezones -CORRECTION KB415539not
KB415439

Thank you Durwin and Bill,

It seems the consensus is to store a copy of each date field into a text
field that represents the 'local' view of the time and then use this for
display purposes.

What concerns me is the effort required by us to address the issue in this
way. As we are developers of  Time & Attendance software, as you would
expect, the software is  a heavy user of date fields.   What compounds this
is the implication of rolling such a change out to 100+ clients.     Not
pretty in a commercial world.

Where our thoughts have evolved to is deploying the eClient so it runs the
same Timezone as the server, so Perth WA in effect, is on the Sydney NSW
Timezone.   This will ensure all data is viewed consistently - I submit
9:00am in Perth it will be displayed as 9:00am in Sydney, etc.    Are there
any gotchas with this, is this heresy, or a viable approach?

This leaves us with cases where we have used SELECT date('now').   My
understanding is this gets the current date and time from the server so
bypasses input from the client.   So if a user clicks on a button to say
they are starting or finishing work it will apply the server view of 'now',
which if I was in Perth and the server in Sydney would be out by 2 hours.

To address this I expect we need to get the current system time from the
local client and use it (where appropriate).   Our audit logs that record
when changes were made by users will need to use this alternate approach.

We have not used any Windows API calls to get the time on the client PC
previously but I expect it is simple enough.

If anyone can see any 'gotchas' with what we are doing we will gladly hear
them!

Thanks.

Regards

Darren Mason

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Durwin Wright
Sent: Friday, 11 April 2008 1:25 AM
To: International OpenROAD Users
Subject: Re: [Openroad-users] eClient & Timezones - CORRECTION KB415539not
KB415439

Hello Darren,

It looks like you are dealing with an artifact of the Ingres implementation
of the INGRES DATE datatype.  Your description of how the INGRES DATE is
stored as GMT in the database is accurate.  When a local client retrieves an
INGRES DATE datatype, it flows across the wire in the GMT normalized form.
Internally in the local client it retrains it's GMT form.  When it is time
to convert the date into a DATE LITERAL is when the timezone offsets are
applied.

We tend to think of the INGRES DATE and the INGRES DATE LITERAL as being
equivalent.  In many cases they do get treated identically. 

Maybe you can try introducing an additional column in which you store the
the INGRES DATE LITERAL value evaluated on the local OpenROAD eClient by
using he VARCHAR(ingresdate) expression.  If you have an Ingres database (or
EA) connection this expression will evaluate to the same value since the
DBMS server will put the session that the client is using into the same
timezone name.  If you have an eClient that uses an OpenROAD Server
connection, the same is not true.

If the Sydney client stores the VARCHAR(ingresdate) value in the database
where the time is 11:00 AM, then when the Perth client retrieves this value
they will also see 11:00 AM.  This can be converted back into an INGRES DATE
value by using the DATE(ingres date liternal) expression.  One caution, is
that when you use this technique, you are effectively using an implicit
INGRES DATE WITHOUT TIMEZONE value.  Do not forget that the INGRES DATE
semantic always assume that the they will be normalized to GMT when they are
passed to the Ingres Server.  

When the eClient passes an INGRES DATE to the OpenROAD Server, it get's
passed also in a GMT normalized form.  The only difference, is that when the
OpenROAD Server passes the date into an Ingres database, it applies the
timezone offset that the OpenROAD Server is set to instead of the timezone
offset of the cleint.

Durwin Wright | Sr. Architect |  <mailto:Durwin.Wright at ingres.com>
Durwin.Wright at ingres.com | Ingres |
<http://maps.google.com/maps?q=500+arguello+street,+94063&ll=37.487297,-122.
233200&spn=0.004602,0.012771&t=k&hl=en> 500 Arguello Street | Suite 200 |
Redwood City | CA | 94063 | USA  +1 650-587-5523 | fax: +1 650-587-5550 

  _____  

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Darren Mason
Sent: Thursday, April 10, 2008 2:39 AM
To: 'International OpenROAD Users'
Subject: Re: [Openroad-users] eClient & Timezones - CORRECTION KB415539not
KB415439

(on behalf of Darren Harvey) 

Thanks for the advice Durwin,

That gives as some ideas on how to ensure we set the correct timezone at
each of our interstate sites. Our immediate thought is to check for an .ini
file on the client PC that will contain the local timezone value,  and if it
does not exists then prompt the user to select a timezone.  Once this has
been done the first time we should be ok from then on. We will start putting
ths in place.  The problem we are trying to resolve leads down the path of
viewing the data after it has been saved.  The following is based on the
Australian timezones.

Let's use Perth in WA where the is at 9:00am , Sydney in NSW where the time
is 11:00am, and GMT being 1:00 at the same time.

What we will be doing is enabling our Perth users to view the time as 9:00am
and save it accordingly - all is good.

Our Sydney users will view their times as 11:00am, and saving it accordingly
so all is good.

Our understanding is that the times are saved in the db as GMT times, so
9:00am in Perth and 11:00am in Sydney will both be saved as 1:00am GMT.
Now we start introducing an issue.

If a Sydney user then access the Perth times, the 9:00am will then be
displayed as 11:00am because it is applying the Sydney - NSW timezone.  The
reverse is true if a user in Perth needed to view times from a Sydney
employee.    11:00 am will be displayed as 9:00am.

We fear needing to introduce text fields to store the times that need to be
displayed on each screen, and I expect reporting will become an issue as it
will be reporting on a collective set of date fields without knowing the
source?

Any advice on how to address this would be greatly appreciated.

Regards

Darren Mason

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Durwin Wright
Sent: Thursday, 10 April 2008 5:59 PM
To: International OpenROAD Users
Subject: Re: [Openroad-users] eClient & Timezones - CORRECTION KB415539 not
KB415439

Are you using the eClient ENVIRONMENT= directive in your eclient in the
INSTALL4GL.TXT file that you use to package the eClient application?  An
excerpt fron the readme.txt for the eCleint is as follows,

    ENVIRONMENT

        This line can appear ZERO or more times.  The string to the right of

        the first "=" sign is treated as an environment variable
specification.

        These environment variables will be set in the eClient runtime
process

        before the OpenROAD runtime is initialized.

        The variable name is separated from the variable value by the second

        "=" sign, similar to the syntax for using "set" in a command window.

        Variable values can refer to other variables using the standard
%xxx%

        syntax (such as in the %II_ECLIENT_APPDIR% example shown above).

        The following "built-in" variables can be referenced by your own

        definitions:

            II_ECLIENT_APPDIR

                This will be set to the current eClient application's

                installation directory, which is also the current directory

                when the OpenROAD runtime executes this eClient application.

            II_ECLIENT_ROOT

                This will be set to the parent directory of the
application's

                installation directory.

            II_ECLIENT_LIBDIR

                This will be set to the eClient shared library installation

                directory.

            (Other predefined variables are described in a later section.)

        Variable definitions are processed in two passes.  First the
variables

        that do not reference any other variables (i.e., those that do not

        contain any "%" characters) are set.  In the second pass, the
variables

        that contain "%" references are expanded using the current
environment

        settings, and then set.

        The order in which variables are processed within each pass is not

        defined.  Therefore, you should not attempt to use more than one
level

        of nesting in your variable definitions.

Normally the II_TIMEZONE_NAME is retrieved from the SYMBOL.TBL for the
nstallation.  The eClient does not use a SYMBOL.TBL.  If there is an Ingres
installation on the machine where the eClient is deployed, then you could
use the ENVIRONMENT directive to set II_SYSTEM to an explicit value.  

An alternative to the SYMBOL.TBL is to explicitly use the SET command to
specific an II_TIMEZONE_NAME vlaue.  This environment variable cannot be set
after the eClient starts the underlying OpenROAD runtime.  The ENVIRONMENT
directive is processed prior to the eClient OpenROAD runtime initializing
and performs a SET on behalf of the eClient prior to the initialization of
the eClient OpenROAD runtime.

Take a look at Ingres KB415539, "How to run an eClient application using
different settings for II_W4GLAPPS_DIR to use different image versions".  It
specifically refers to II_W4GLAPPS_DIR but the technique cold easily be
generalized to having a previously Windows environment variable set that
contains the local value of II_TIMEZONE_NAME.

Durwin Wright | Sr. Architect |  <mailto:Durwin.Wright at ingres.com>
Durwin.Wright at ingres.com | Ingres |
<http://maps.google.com/maps?q=500+arguello+street,+94063&ll=37.487297,-122.
233200&spn=0.004602,0.012771&t=k&hl=en> 500 Arguello Street | Suite 200 |
Redwood City | CA | 94063 | USA  +1 650-587-5523 | fax: +1 650-587-5550 

  _____  

From: openroad-users-bounces at peerlessit.com
[mailto:openroad-users-bounces at peerlessit.com] On Behalf Of Darren Harvey
Sent: Wednesday, April 09, 2008 7:17 PM
To: 'International OpenROAD Users'
Subject: [Openroad-users] eClient & Timezones

I have a question re the handling of Timezones within an eClient
environment.  

Assume the time in NSW is 11:00 and Western Australia is 09:00.

We have built the Cab file through the OR Web-Publisher and specified an
environment parameter of 'II_TIMEZONE_NAME=AUSTRALIA-NSW'.  This works fine
in NSW, however when users in Western Australia run the eClient, they see
the 'current' time as 11:00 instead of the correct local time of 09:00.  (I
assume this is correct from an OR point of view? But unfortunately it isn't
what we require.)

Does this mean we need to build a separate Web application for Western
Australian users, that specifies a parameter of
'II_TIMEZONE_NAME=AUSTRALIA-WEST'? And that this would then show the
'current' time as 09:00.

I hope this makes sense.

Thanks

Darren

Regards

Darren Harvey

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