The following bug has been logged online: Bug reference: 5806 Logged by: Leslie Satenstein Email address: lsatenst...@yahoo.com PostgreSQL version: 8.4 + 9.0 Operating system: Linux 64bit Description: Julian Date routine miscalculates. Details:
I found the Julian date code that is programmed in Postgres, to be accurate and fast except for one situation. But, I do have one or two questions. 1) Which calendar is being used? In the Gregorian Calendar, January 1, 0001 is lowest > positive date. The day before 1/1/0001, according to the Gregorian calendar is December 31,-0001 in which the year has a value of negative one --- there is no zero year in the Gregorian Calendar. (zero year is an error) I tested and found the algorithm in Postgres to have the day before January 1,0001 calculating as December 31,0000 even though the world calculates the day before January 1,0001 as December 31,-0001. 2) Is the algorithm in Postgres correct? I think not, as the calculations for the difference in days between January 1, 0001 and December 31,-0001 is not 367 days, but just the value 1. To convert the code to work with the Gregorian calendar takes two fixes to two sub-routines. Each fix is two lines of C code. I have tested the PG Date C language routines with/without my fix, starting with the year around -4713 to several centuries into the future. As long as both versions do not deal with negative dates both calculate identically. 3) Does PG want to fully follow the Gregorian Calendar rule? If so, 4) Would you want my one patch with two fixes that would allow calculating any two dates later in time than -4711. -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
