Thread

1. Numeric modulo operator is incorrect.

   Ken-ichi Yamasaki <yama@yuzu.gr.jp> — 2001-04-07T09:33:36Z

   Dear sir,
   
   I build PostgreSQL 7.0.3 with jumbo-20010318.patch.gz on Vine Linux2.1.5.
   
   Following result are incorrect. Am I under an illusion?
   
   test=# select '34666624082'::numeric % '34666671'::numeric;
    ?column? 
   ----------
      -46918
   (1 row)
   
   test=# select '34666624082'::numeric - '34666671'::numeric
   	* trunc('34666624082'::numeric / '34666671'::numeric);
    ?column? 
   ----------
    34619753
   (1 row)
   
   
   

2. Re: Numeric modulo operator is incorrect.

   Tom Lane <tgl@sss.pgh.pa.us> — 2001-04-13T19:54:46Z

   Ken-ichi Yamasaki <yama@yuzu.gr.jp> writes:
   > I build PostgreSQL 7.0.3 with jumbo-20010318.patch.gz on Vine Linux2.1.5.
   
   > Following result are incorrect. Am I under an illusion?
   
   > test=# select '34666624082'::numeric % '34666671'::numeric;
   >  ?column? 
   > ----------
   >    -46918
   > (1 row)
   
   This is a bug; looks like mod_var() is using a rather silly estimate
   of how many digits of precision it needs to keep in the division step.
   
   I have a fix but I'm not sure if it will get into 7.1 or be held
   for 7.1.1 ...
   
   			regards, tom lane