Обсуждение: Is TimeZone applied with TIMESTAMP WITHOUT TIME ZONE and Extract( EPOCH ...)?

I'm noticing some interesting behavior around timestamp and extract epoch, and it appears that I'm getting a timezone applied somewhere.

Specifically, If I do:
select EXTRACT( EPOCH FROM '2010-01-31 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1264924800
select EXTRACT( EPOCH FROM '2010-04-01 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1270105200

Now if I do something similar in Java.. using a GregorianCalendar, with "GMT" TimeZone.
I get
Hello:2010-01-31 00:00:00.000 (UTC)
Hello:1264896000000

Hello:2010-04-01 00:00:00.000 (UTC)
Hello:1270080000000

Which gives a difference of 8 and 7 hours respectively, so both a timezone and a DST shift are at work here.

Is this the expected behavior of extract epoch, is there a way to get it to always be in GMT?

Looks like a quick search says I need to specify the timezone...

On Thu, Mar 17, 2011 at 11:22 AM, bubba postgres <bubba.postgres@gmail.com> wrote:

I'm noticing some interesting behavior around timestamp and extract epoch, and it appears that I'm getting a timezone applied somewhere.

Specifically, If I do:
select EXTRACT( EPOCH FROM '2010-01-31 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1264924800
select EXTRACT( EPOCH FROM '2010-04-01 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1270105200

Now if I do something similar in Java.. using a GregorianCalendar, with "GMT" TimeZone.
I get
Hello:2010-01-31 00:00:00.000 (UTC)
Hello:1264896000000

Hello:2010-04-01 00:00:00.000 (UTC)
Hello:1270080000000

Which gives a difference of 8 and 7 hours respectively, so both a timezone and a DST shift are at work here.

Is this the expected behavior of extract epoch, is there a way to get it to always be in GMT?

no.. still confused.
I assume it's storing everythign in UTC.. did I need to specify a timezone when I inserted?

On Thu, Mar 17, 2011 at 11:24 AM, bubba postgres <bubba.postgres@gmail.com> wrote:

Looks like a quick search says I need to specify the timezone...

On Thu, Mar 17, 2011 at 11:22 AM, bubba postgres <bubba.postgres@gmail.com> wrote:

I'm noticing some interesting behavior around timestamp and extract epoch, and it appears that I'm getting a timezone applied somewhere.

Specifically, If I do:
select EXTRACT( EPOCH FROM '2010-01-31 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1264924800
select EXTRACT( EPOCH FROM '2010-04-01 00:00:00'::TIMESTAMP WITHOUT TIME ZONE ); == 1270105200

Now if I do something similar in Java.. using a GregorianCalendar, with "GMT" TimeZone.
I get
Hello:2010-01-31 00:00:00.000 (UTC)
Hello:1264896000000

Hello:2010-04-01 00:00:00.000 (UTC)
Hello:1270080000000

Which gives a difference of 8 and 7 hours respectively, so both a timezone and a DST shift are at work here.

Is this the expected behavior of extract epoch, is there a way to get it to always be in GMT?