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Thread: Day Light Savings Problem

Day Light Savings Problem

From
Pallav Kalva
Date:
Hi,


    As per this article

http://people.planetpostgresql.org/greg/index.php?url=archives/96-Is-your-database-ready-for-the-Daylight-Savings-Times-change-of-2007.html&serendipity[cview]=linear#comments,
My postgres 8.0.2 database has a problem with the new day light savings
time change this month.

So, I upgraded it to the latest 8.0 version which is 8.0.12 and below
you will see the output of the case statement and also the timezone
file. As you can see the case statement says that timezone value is
fixed but where as the timezone file still has the old values.

    Is this a bug ? why cant it show the new timezone values in the
timezone file  ? I even looked at the 8.2.1 timezone file it also has
the old values.

    Can I use this postgres 8.0.12 version for the day light savings
problem.

===========================================================
postgres@pkalva:/var/lib/pgsql/bin> ./psql template1
Welcome to psql 8.0.12, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
       \h for help with SQL commands
       \? for help with psql commands
       \g or terminate with semicolon to execute query
       \q to quit

template1=# SET TIMEZONE = 'EST5EDT';
SET
template1=#
template1=# SELECT CASE WHEN
template1-#   timestamptz '20070401 0100'
template1-#   + interval '1 hour'
template1-#   >= '20070401 0300'
template1-#   THEN 'Wrong' ELSE 'Right' END;
 case
-------
 Right
(1 row)

template1=# \q
postgres@pkalva:/var/lib/pgsql/bin> cd ..
postgres@pkalva:/var/lib/pgsql> cd share
postgres@pkalva:/var/lib/pgsql/share> /usr/sbin/zdump -v EST5EDT | grep 2007
EST5EDT  Sun Apr  1 06:59:59 2007 UTC = Sun Apr  1 01:59:59 2007 EST
isdst=0 gmtoff=-18000
EST5EDT  Sun Apr  1 07:00:00 2007 UTC = Sun Apr  1 03:00:00 2007 EDT
isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 28 05:59:59 2007 UTC = Sun Oct 28 01:59:59 2007 EDT
isdst=1 gmtoff=-14400
EST5EDT  Sun Oct 28 06:00:00 2007 UTC = Sun Oct 28 01:00:00 2007 EST
isdst=0 gmtoff=-18000

Re: Day Light Savings Problem

From
Tom Lane
Date:
Pallav Kalva <pkalva@livedatagroup.com> writes:
> postgres@pkalva:/var/lib/pgsql/bin> cd ..
> postgres@pkalva:/var/lib/pgsql> cd share
> postgres@pkalva:/var/lib/pgsql/share> /usr/sbin/zdump -v EST5EDT | grep 2007
> EST5EDT  Sun Apr  1 06:59:59 2007 UTC = Sun Apr  1 01:59:59 2007 EST
> isdst=0 gmtoff=-18000

Are you sure that zdump looks into the current directory?  The man page
is not clear but it says the arguments are "zone names" not "file names",
so I'd sort of expect that it's looking into the system timezone
directory.  In which case this result means that your OS is in need of
a timezone update, not Postgres.

            regards, tom lane

Re: Day Light Savings Problem

From
Pallav Kalva
Date:
Hi Tom,

    You are right , I re reran the command now with the whole path it
worked.  It was looking at the OS time

========================================================================================
postgres@pkalva:/var/lib/pgsql/share/timezone> /usr/sbin/zdump -v
/var/lib/pgsql/share/timezone/EST5EDT | grep 2007
/var/lib/pgsql/share/timezone/EST5EDT  Sun Mar 11 06:59:59 2007 UTC =
Sun Mar 11 01:59:59 2007 EST isdst=0 gmtoff=-18000
/var/lib/pgsql/share/timezone/EST5EDT  Sun Mar 11 07:00:00 2007 UTC =
Sun Mar 11 03:00:00 2007 EDT isdst=1 gmtoff=-14400
/var/lib/pgsql/share/timezone/EST5EDT  Sun Nov  4 05:59:59 2007 UTC =
Sun Nov  4 01:59:59 2007 EDT isdst=1 gmtoff=-14400
/var/lib/pgsql/share/timezone/EST5EDT  Sun Nov  4 06:00:00 2007 UTC =
Sun Nov  4 01:00:00 2007 EST isdst=0 gmtoff=-18000
========================================================================================

Thanks!
Pallav




Tom Lane wrote:
> Pallav Kalva <pkalva@livedatagroup.com> writes:
>
>> postgres@pkalva:/var/lib/pgsql/bin> cd ..
>> postgres@pkalva:/var/lib/pgsql> cd share
>> postgres@pkalva:/var/lib/pgsql/share> /usr/sbin/zdump -v EST5EDT | grep 2007
>> EST5EDT  Sun Apr  1 06:59:59 2007 UTC = Sun Apr  1 01:59:59 2007 EST
>> isdst=0 gmtoff=-18000
>>
>
> Are you sure that zdump looks into the current directory?  The man page
> is not clear but it says the arguments are "zone names" not "file names",
> so I'd sort of expect that it's looking into the system timezone
> directory.  In which case this result means that your OS is in need of
> a timezone update, not Postgres.
>
>             regards, tom lane
>