Strange sybase behavior around daylight savings time (DST) - sap-ase

I've got a strange sybase behavior which I do not understand.
Situation
I have a table (MY_TABLE) with several columns of type smalldatetime. For illustration purposes let's assume the following table and data:
MY_TABLE||ID |TS_INIT |TS_LASTCHANGE |MY_TEXT |
||4711|3/31/2013 12:00:00 AM|3/31/2013 3:00:00 AM|someText|
TS_INIT and TS_LASTCHANGE are of type smalldatetime.
When executing the following statement I get the above result:
SELECT ID, TS_INIT, TS_LASTCHANGE MY_TEXT
FROM MY_TABLE
WHERE ID = 4711
go
My client is running in UTC+1 (Berlin) and has daylight savings time (DST) enabled.
I am not sure in what time zone the server is running and whether or not DST is enabled.
Problem
When I execute this (note that it is 03:00h):
SELECT ID, TS_INIT, TS_LASTCHANGE MY_TEXT
FROM MY_TABLE
WHERE ID = 4711 AND TS_LASTCHANGE = "2013-03-31 03:00:00:000"
go
I get NO results but when I execute this (note that it is 02:00h this time):
SELECT ID, TS_INIT, TS_LASTCHANGE MY_TEXT
FROM MY_TABLE
WHERE ID = 4711 AND TS_LASTCHANGE = "2013-03-31 02:00:00:000"
go
I do again get the above result which is saying TS_LASTCHANGE is
3/31/2013 3:00:00 AM
Note that the result prints 03:00h, even though I queried for 02:00h.
Why Is the first query returning no results even though there should be a match and why is the second query returning a result even though there should be no match?!
Note also that 3/31/2013 3:00:00 AM is the first moment in DST (at least in the year 2013) and 3/31/2013 2:00:00 AM should never ever exist at all because when transitioning from winter to summer time, the clock switches from 01:59:59 to 03:00:00 (as per this site).
Database: Adaptive Server Enterprise V15.0.3
Client: Aqua Data Studio V16.0.5
EDIT:
When querying whit the TS_INIT everything works as one would expect (only a result for 3/31/2013 12:00:00 AM)

Aqua Data Studio is written in Java.
The problem you are having has to do with the fact that Java is aware of timezones and databases don't have a concept of timezone when they store date and times. When the time comes back from the database, the database's JDBC driver puts it in a Java date and just assumes the timezone is irrelevant. The problem happens when you try to display a time which the JVM thinks is invalid, so a valid date is presented, which basically pushes the time by an hour. Daylight savings for 2015 started on March 08 2.00 AM and one of your rows contains a date which is invalid according to JVM.
This has been a known design issue with Java, and they are trying to fix this with JSR-310 for inclusion in Java SE 8. With this, they will have LocalDate, OffsetDate and ZonedDate. You can read more about it here ...
https://today.java.net/pub/a/today/2008/09/18/jsr-310-new-java-date-time-api.html#jsr-310-datetime-concepts
https://jcp.org/en/jsr/detail?id=310
http://docs.google.com/View?id=dfn5297z_8d27fnf
Workaround
The only workaround, is to probably trick the JVM by setting the timezone in the JVM to GMT. If you are running ADS 16 on Windows, and you launch ADS with the shortcut icon on the desktop (which runs datastudio.exe), then you need to modify the datastudio.ini file in your folder. Add a new entry for vmarg.5=-Duser.timezone=gmt
This link explains the location of where to find the data studio.ini
https://www.aquaclusters.com/app/home/project/public/aquadatastudio/wikibook/Documentation14/page/50/Launcher-Memory-Configuration#windows
Once you have made the change, Restart ADS. Then go to Help->About->System: and double check your user.timezone setting and make sure it is GMT. Then give it a try.
With the above change there might be side effects in the application where timezone are involved, For e.g. in the Table Data Editor->Insert Current Date&Time, which would display a GMT time ... so there would be an offset.

Related

Dialogflow console returning different result to when sent through the API (Where the wrong timezone is used)

I have a DialogFlow agent set up where one intent is used to schedule reminders. I can say something like:
"At 5pm remind me to go for a run"
And it returns the sentence to remind (in this case 'go for a run') as well as the time to set the reminder using #sys.date-time.
This works as intended, I am able to get the correct time because it just sends the time without a timezone attached.
When I use a command such as:
"In 15 minutes remind me to go for a run"
it sends the result as the time using the timezone, in this case, the incorrect one.
So right now, a result for the date-time using the API was:
2020-11-09T14:20:33+01:00
which is an hour more than it should be.
I have checked the DialogFlow agent's default time zone where it is set to:
(GMT0:00) Africa/Casablanca
Which I am fairly certain is the correct one for London time. However moving to a different timezone changes it and actually gives the correct one for the timezone (Just not my timezone)
Leaving me to wonder if this time zone is broken?
Regardless though, the Dialogflow console on the webpage returns the correct date-time but in a different format using 'startDateTime' and 'endDateTime', something that the agent does not do when sent using the API.
I have checked all configurations within the program and cannot find any evidence of any code giving a new timezone and in fact have tried to add the London timezone when a query is sent but this does not resolve the issue.
Does anyone have any advice on how to solve this?
EDIT:
After receiving a good suggestion from a user I am reminded of the most puzzling part of this issue. Chaning the timezone to GMT -1:00 vs 0:00 actually having a difference of two hours.
Around 1pm I queried it to get the time in 15 minutes.
When it was set to GMT-1:00 Atlantiv/Cape_Verde the time returned is:
2020-11-10T12:21:15-01:00
When it was set to GMT0:00 Africa/Casablanca the time returned is:
2020-11-10T14:22:07+01:00
Neither is the correct time and despite the timezone suggesting a 1 hour difference, it is actually 2 hours apart.
For London the correct timezone should be GMT -1, Casablanca Africa is GMT+1, I used this web page to determine this.
If you are in London is recommended to configure your agent to sue the correct time zone (GMT-1).

Understanding GTFS service times

I have a problem with the understanding of the gtfs file format. Or maybe there is an error in that data. There is a gtfs file from a public transportation agency called "Verkehrsverbund Mittelthüringen" (VMT). This data is accessible at https://transitfeeds.com/p/verkehrsverbund-mittelth-ringen/1080/latest/routes.
For example: I have taken the trip with the ID 9782458 (trips.txt).
2841_0,45,9782458,"Erfurt, Thüringenhalle","",0,,,,
This has the service ID 45 with the specification
45,0,0,0,0,0,0,0,20191101,20200229
Additionally here are the entries for the celendar_dates.txt
45,20191104,1
45,20191111,1
45,20191118,1
45,20191125,1
45,20191202,1
45,20191209,1
45,20191216,1
45,20191105,1
45,20191112,1
45,20191119,1
45,20191126,1
45,20191203,1
45,20191210,1
45,20191217,1
45,20191106,1
45,20191113,1
45,20191120,1
45,20191127,1
45,20191204,1
45,20191211,1
45,20191218,1
45,20191107,1
45,20191114,1
45,20191121,1
45,20191128,1
45,20191205,1
45,20191212,1
45,20191219,1
45,20191101,1
45,20191108,1
45,20191115,1
45,20191122,1
45,20191129,1
45,20191206,1
45,20191213,1
45,20191220,1
Does this mean, that the service is available all times, except from the 1st November 2019 to the 29th February 2020? My Problem now is the output of the search engine tansitfeeds.com. It says the trip with the ID 9782458 is available at the 14th November 2019. Which is contary to my understanding of the data: the trip won't be available in November. Where is the clue I missed? Or is there an error in the data?
The line you pasted indicates that service ID 45 runs on zero days of the week (that's what all those zeros mean), so the start and end dates in the same line don't really mean anything.
If this service actually does run on Nov. 14, this could be represented in the calendar_dates.txt file, which is usually used to represent service changes for special dates.
EDIT: the data you added from calendar_dates.txt does indeed show that service 45 has been added for date 20191114.

TZD database missing transitions?

I'm using version 'TZDB: 2018c (mapping: 13290)' of the TZD db however when I ask for Pacific/Auckland timezone information using either
VTimeZone.FromTzId(tzdbId);
or
VTimeZone.FromTzId(tzdbId, earliestDateTimeToSupport, true);
If I use 2008-01-01 as earliestDateTimeToSupport I'll get the current daylight saving details and recurrence rules. If however I use any date after that or NO date I'll get UTC -11 (WHEN was that rule last in play??? not while I've been alive.) and the recurrence rule looks all wrong. Can anyone advise if this is the DB or something I'm likely to be doing?
Australia/Sydney seems to behave properly... they've had a timezone change during 2008 and that rule comes through... and I'm not going to test them all but I think this is just a fault with NZDST for dates post (ish) 2009-1-1.

How to set date time format in Logic App

I have created an API which creates an excel having Date columns too. When I execute the code from local it works well and displays the date as expected.
When I try executing API via Logic App, it changes the date format of that field. How can I set date time in Logic App?
When you have a fixed DateTime-Format you can use the Logic App function "formatDateTime" as follow:
formatDateTime(triggerBody()?['myDate'], 'yyyy-MM-dd')
You can find it under Expressions - Date and Time - "See more" - formatDateTime
I found some useful documentation on Microsoft's site here:
https://learn.microsoft.com/en-us/azure/kusto/query/format-datetimefunction
Here it is .. in action:
Try this to get the current date in GMT format:
The problem is your local machine is running a different Locale than the machine running your code when it is deployed.
You could either set the CultureInfo.CurrentCulture to make sure the right CultureInfo is used.
CultureInfo...
Provides information about a specific culture (called a locale for unmanaged code development). The information includes the names for the culture, the writing system, the calendar used, the sort order of strings, and formatting for dates and numbers.
You could also use the appropriate DateTimeFormatInfo, when writing the date to Excel, it
Provides culture-specific information about the format of date and time values.
Logic apps time zone base on UTC. So, it needs conversion between UTC to your local time.
In my case, 'SE Asia Standard Time', (UTC+07:00); Bangkok, Hanoi, Jakarta. So, you need to convert it as your local time. Here's in my case:
Date convertTimeZone(utcNow(), 'UTC', 'SE Asia Standard Time', 'MMMM dd, yyyy');
Time convertTimeZone(utcNow(), 'UTC', 'SE Asia Standard Time','hh:mm:ss.ff tt')

Records get skipped Due to timeZone difference between Server and cllients in Nodejs Rethinkdb?

iam filtering some records from my Rethinkdb . the code works just fine when i use the following code . but it works with date only
(new Date(filter.fromdate+' 00:00 GMT+00:00'));
the line above works perfect even after the server is on different region. By using above . It wont skipp any records and time and date just works fine .
but when i use date with time it throws error of rangeError invalid time
I am saving date in rethink in the following format Mon Feb 20 2017 07:25:27 GMT+00:00
SomeHow i just need time with my date to work with the above mentioned code or may be other method can also be used .
Ok, so you need to check if filter.fromdate is with time:
If with time don't add your time and modify it with the proper method of Date , otherwise if is a date without time add your time. And remember you can use momentjs instead of Date to handle dates. Hope help you man.

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