[Deploying Sakai] Time zone mismatch on sakai 2.8

[Yzelle, Sonette]

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Hi,

We experienced the same problem at Unisa, we also came to the conclusion that it was Oracle related.
We ended up adding an oracle trigger on insert/update to the sakai_session and sakai_event tables to add 2 hours to the time to be written away so that correct time reflects in the tables.

Sonette


Sonette Yzelle
Portal and Academic Solutions
ICT
UNISA
(012) 429-6259

From: production-bounces at collab.sakaiproject.org [mailto:production-bounces at collab.sakaiproject.org] On Behalf Of Matthew Jones
Sent: 29 November 2011 06:28 PM
To: Mike De Simone
Cc: production at collab.sakaiproject.org; Eduardo
Subject: Re: [Deploying Sakai] Time zone mismatch on sakai 2.8

Yea, mysql Might do some background processing on the field that Oracle isn't

"TIMESTAMP<http://dev.mysql.com/doc/refman/5.0/en/datetime.html> values are converted from the current time zone to UTC for storage, and converted back from UTC to the current time zone for retrieval." - http://dev.mysql.com/doc/refman/5.0/en/timestamp.html

Timestamp for Oracle has TIMESTAMP, TIMESTAMP WITH TIMEZONE and TIMESTAMP WITH LOCAL TIMEZONE. http://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements001.htm

I think most of the fields are TIMESTAMP WITH TIMEZONE. Super confusing!
Internally MyTime returns all UTC from the Java call System.currentTimeMillis().

It probably is only a problem if you try to convert after the system is running, or if you're not familiar with what your system is setup as. This all sounds super confusing to me, especially the 3 different Oracle version. This page agrees. ;)

"This data type is very confusing and is to be avoided at all costs." - http://puretech.paawak.com/2010/11/02/how-to-handle-oracle-timestamp-with-timezone-from-java/

-Matthew

On Tue, Nov 29, 2011 at 10:42 AM, Mike De Simone <michael.desimone at rsmart.com<mailto:michael.desimone at rsmart.com>> wrote:
This might be an oracle thing.  I just checked MySQL that's running Sakai 2.8 and events & session times are in the local time rather than GMT.  I do actively set the timezone as a java system property, so maybe that overrides something?

e.g., in setenv.sh: JAVA_OPTS="$JAVA_OPTS -Duser.timezone=US/Pacific"


Thanks,

-------------------------------
Mike DeSimone
Lead Systems Engineer
rSmart | 602-490-0473<tel:602-490-0473>


On Tue, Nov 29, 2011 at 08:37, Matthew Jones <jonespm at umich.edu<mailto:jonespm at umich.edu>> wrote:
FYI: Sakai Events (and other fields that store the date/time like session) are stored in GMT. This is because it will be the only time that is ever constant. It's possibly your data center could relocate, you could have daylight savings time. GMT never changes with seasons and is always a constant.

Here's some additional information from a post a few years ago.
http://collab.sakaiproject.org/pipermail/sakai-dev/2009-September/003731.html

-Matthew

On Tue, Nov 29, 2011 at 8:46 AM, Eduardo <eduzav at hotmail.com<mailto:eduzav at hotmail.com>> wrote:
Hy, we're using Sakai 2.8 on Argentina and we have difference time between application and database ( three hours mismatch)
Example: when a user logs on application at 17hs the sesión_start field on table is 20hs


The time zone of Argentina is GMT -3.

All servers (backend and frontends) are synchronizing the hour using ntp protocol (ar.pool.ntp.org<http://www.pool.ntp.org/zone/ar>) and the time zone configurated is GMT+3 (the operating systems are OEL 5.5)

On backend we're using Oracle 10g release 4 and the time configurated on instance is OK.

select systimestamp from dual;
29/11/2011 10:32:06,241764 AM -03:00
select current_timestamp from dual;
29/11/2011 10:29:39,827614 AM -03:00

The time on application layout is Ok but the time on oracle table is incorrect.
The table we're monitoring is sakai.session and the fields are SESSION_START and SESSION_END.

On the other hand catalina evironment is:

CATALINA_OPTS='-server -Xms512m -Xmx3072m -XX:PermSize=128m -XX:MaxPermSize=512m -XX:NewSize=192m -XX:MaxNewSize=384m -Djava.awt.headless=true -Dhttp.agent=Sakai -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Dsun.lang.ClassLoader.allowArraySyntax=true -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=33331 -Dcom.sun.management.jmxremote.ssl=false  -Dcom.sun.management.jmxremote.authenticate=false -Duser.language=es -Duser.region=ES'

I don't know how can I fix that error, what do you suggest me?

Thanks,
Eduardo Zavala




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