Thread

1. pg_dump and psql disagree on numerical precision (powerpc)

   Christof Petig <christof@petig-baender.de> — 2003-11-14T09:55:42Z

   I didn't believe it at first:
   
   create table test ( x double precision);
   
   insert into test values (0.3);
   
   test=# select * from test;
      x
   -----
     0.3
   
   --
   -- Data for TOC entry 3 (OID 53248)
   -- Name: test; Type: TABLE DATA; Schema: public; Owner: christof
   --
   COPY test (x) FROM stdin;
   0.29999999999999999
   \.
   
   psql --version
   psql (PostgreSQL) 7.4RC1
   
   \set
   VERSION = 'PostgreSQL 7.4RC1 on powerpc-unknown-linux-gnu, compiled by 
   GCC powerpc-linux-gcc (GCC) 3.3.2 (Debian)'
   
   pg_dump --version
   pg_dump (PostgreSQL) 7.4RC1
   
   
   

2. Re: pg_dump and psql disagree on numerical precision (powerpc)

   Tom Lane <tgl@sss.pgh.pa.us> — 2003-11-14T14:50:32Z

   Christof Petig <christof@petig-baender.de> writes:
   > COPY test (x) FROM stdin;
   > 0.29999999999999999
   > \.
   
   This is not a bug; it's pg_dump trying to recreate the actual floating
   point value as accurately as it can.  See the discussion of
   extra_float_digits from six months or a year back.
   
   			regards, tom lane
   
   

3. Re: pg_dump and psql disagree on numerical precision (powerpc)

   Christof Petig <christof@petig-baender.de> — 2003-11-14T15:47:10Z

   Tom Lane schrieb:
   > Christof Petig <christof@petig-baender.de> writes:
   > 
   >>COPY test (x) FROM stdin;
   >>0.29999999999999999
   >>\.
   > 
   > 
   > This is not a bug; it's pg_dump trying to recreate the actual floating
   > point value as accurately as it can.  See the discussion of
   > extra_float_digits from six months or a year back.
   
   Oh, I see (and generally appreciate). Thank you for reminding me.
   
   Commenting out "set extra_float_digits=2" in pg_dump.c gives me the old 
   behaviour. Is it only me wishing for a command line parameter for 
   pg_dump to set desired precision?
   
       Christof
   
   
   

4. Re: pg_dump and psql disagree on numerical precision (powerpc)

   Tom Lane <tgl@sss.pgh.pa.us> — 2003-11-14T16:25:07Z

   Christof Petig <christof@petig-baender.de> writes:
   > Commenting out "set extra_float_digits=2" in pg_dump.c gives me the old 
   > behaviour. Is it only me wishing for a command line parameter for 
   > pg_dump to set desired precision?
   
   It seems to me that you should be using type NUMERIC if you think there
   is a difference between 0.3 and 0.29999999999999999.
   
   			regards, tom lane
   
   

5. Re: pg_dump and psql disagree on numerical precision (powerpc)

   Christof Petig <christof@petig-baender.de> — 2003-11-14T22:07:46Z

   Tom Lane schrieb:
   > Christof Petig <christof@petig-baender.de> writes:
   > 
   >>Commenting out "set extra_float_digits=2" in pg_dump.c gives me the old 
   >>behaviour. Is it only me wishing for a command line parameter for 
   >>pg_dump to set desired precision?
   > 
   > 
   > It seems to me that you should be using type NUMERIC if you think there
   > is a difference between 0.3 and 0.29999999999999999.
   
   Touché. (you score)
   
      Christof