Thread

1. date_part returns wrong day for 1974-04-28

   PostgreSQL Bugs List <pgsql-bugs@postgresql.org> — 2001-04-09T18:21:11Z

   Phil Steinke (lintec@clarkhall.ca) reports a bug with a severity of 2
   The lower the number the more severe it is.
   
   Short Description
   date_part returns wrong day for 1974-04-28
   
   Long Description
   The date_part function is returning the wrong value for the date 1974-04-28.  It seems to work with other similar dates (+/- a day, +/- a year).
   
   I'm using:
                               version                            
   ---------------------------------------------------------------
    PostgreSQL 7.0.3 on i686-pc-linux-gnu, compiled by gcc 2.95.2
   
   Specifically, the postgresql_7.0.3-4 package from Debian unstable (sid), on a Pentium 100 with 32 megs of RAM (10MB still free though).
   
   Feel free to contact me for more information.
   
   
   Sample Code
   select date_part('day', date('1974-04-28'));
   
   
   No file was uploaded with this report
   
   
   

2. Re: date_part returns wrong day for 1974-04-28

   Thomas Lockhart <lockhart@alumni.caltech.edu> — 2001-04-09T20:40:47Z

   > Short Description
   > date_part returns wrong day for 1974-04-28
   > Long Description
   > The date_part function is returning the wrong value for the date 1974-04-28.  It seems to work with other similar dates (+/- a day, +/- a year).
   > Feel free to contact me for more information.
   
   You are likely running across a "known feature" in PostgreSQL for
   versions before the almost-here v7.1. I do not know which time zone you
   are running in (need that info!) but in the US Pacific Time Zone
   1973-1975 have variations due to the first energy crisis resulting from
   the war in the Middle East. April 28 is not a significant date in my
   time zone, but may be in yours.
   
                           - Thomas
   
   

3. Re: date_part returns wrong day for 1974-04-28

   Phil Steinke <lintec@clarkhall.ca> — 2001-04-09T22:30:17Z

   * Thomas Lockhart was mumbling about..
   > You are likely running across a "known feature" in PostgreSQL for
   > versions before the almost-here v7.1. I do not know which time zone you
   > are running in (need that info!) but in the US Pacific Time Zone
   
   Aha..  I'm in Eastern (Canada), and doing this for any switch from EST to
   EDT causes the problem.. e.g. April 1st of this year:
   
   => select timestamp(date('2001-04-01'));
          timestamp
   ------------------------
    2001-03-31 23:00:00-05
   (1 row)
   
   This skewed timestamp then gives the wrong day for the date_part.  I think
   that time switches in EST/EDT are supposed to happen at 2am, not midnight,
   to help avoid this kind of thing.
   
   Phil