bug in timestamp and out of range values

We found the problem on one of our production 8.1 servers; a big concern is
that it breaks dumps (allows you to dump a table with a value that can't be
restored). Seems to be a problem in 8.2 as well. Here is the test case:

pagila=# create table t1 (c1 timestamp);
CREATE TABLE
pagila=# select to_date('3232098', 'MM/DD/YYYY');
to_date
---------------
4568-06-26 BC
(1 row)

pagila=# insert into t1 select to_date('3232098', 'MM/DD/YYYY');
INSERT 0 1
pagila=# select * from t1;
ERROR: timestamp out of range
pagila=#
pagila=#
pagila=# truncate t1;
TRUNCATE TABLE
pagila=# alter table t1 add check (c1 > '1900-01-01'::timestamp and c1
< '2100-01-01'::timestamp);
ALTER TABLE
pagila=# insert into t1 select to_date('3232098', 'MM/DD/YYYY');
ERROR: new row for relation "t1" violates check constraint "t1_c1_check"
pagila=#
pagila=#

here are some relevant irc logs discussing this:

16:41 < xzilla_> anyone have a copy of 8.2 handy ?
16:42 < AndrewSN> xzilla: yes, but it's a couple of weeks old
16:42 < xzilla> AndrewSN: s'ok... can you try and reproduce the following
error http://rafb.net/paste/results/PsPZDf57.html
16:44 < AndrewSN> xzilla: yes, I get that same result
16:45 < xzilla> guess i am obligated to send it to -bugs now :-)
16:46 < Primer> indeed
16:46 < AndrewSN> xzilla: is it a bug in to_date, the date->timestamp cast, or
timestamp_out, or all three?
16:52 < xzilla> AndrewSN: i dont think it is in to_date
16:53 < xzilla> AndrewSN: nor date->timestamp cast
16:53 < AndrewSN> xzilla: the timestamp value actually being stored in the
table is: -214839043200
16:53 < xzilla> AndrewSN: was thinking that it should have tossed an error on
insert of the invalid timestamp value
16:54 < xzilla> AndrewSN: how did you determine that ?
16:54 < AndrewSN> postgres=# select encode(timestamp_send(c1),'hex') from x1;
16:54 < AndrewSN> encode
16:54 < AndrewSN> ------------------
16:54 < AndrewSN> c24902b3d2400000
16:55 < AndrewSN> compare:
16:55 < AndrewSN> postgres=# select encode(float8send(-214839043200),'hex')
from x1;
16:55 < AndrewSN> encode
16:55 < AndrewSN> ------------------
16:55 < AndrewSN> c24902b3d2400000
16:55 < AndrewSN> (1 row)
16:55 < xzilla> AndrewSN: interesting
16:56 < AndrewSN> xzilla: what do you think should have tossed the error if
not the date->timestamp cast function?
16:57 < xzilla> AndrewSN: a check constraint on a timestamp range will cause
an error to be raised, which made me think it wasnt the
date->timestamp cast
16:58 < AndrewSN> xzilla: the "timestamp out of range" error is coming from
timestamp_out
16:58 < xzilla> http://rafb.net/paste/results/cTLlv583.html
16:59 < AndrewSN> xzilla: well, of course, because the result you're getting
from to_date is not in that range
17:00 < xzilla> AndrewSN: sure, but it also implies the result i am getting is
a valid timestamp
17:02 < AndrewSN> xzilla: ok, I think I see
17:02 < AndrewSN> xzilla: what happens is that timestamp_out barfs if the
Julian day would be negative.
17:02 < AndrewSN> xzilla: but the internal representation of timestamp is
quite happy to represent values earlier than that
17:05 < AndrewSN> xzilla: so I think, in fact, the problem is in to_date
17:06 < AndrewSN> xzilla: because to_date should not be returning negative
julian dates
17:06 -!- leafw [n=Any(at)cbg-off-client(dot)mpi-cbg(dot)de] has joined #postgresql
17:08 < AndrewSN> xzilla: note that date_out's display of '4568-06-26 BC' is
bogus, the date value being returned is much earlier
17:09 < xzilla> AndrewSN: if the internal representation of timestamp is happy
to represent the value, then isnt the problem in timestamp_out
(and the effects of to_date are only a side effect of how i
got the data in there)
17:09 < AndrewSN> eevar: select * from pg_language;
17:10 < AndrewSN> xzilla: arguably all of to_date, the date->timestamp cast
and timestamp_out are broken
17:11 < xzilla> AndrewSN: ok, i could see that :-) btw, if i do create
table t2 as select * from t1 i now have a table with the bad
timestamp that didnt directly require to_date
17:12 < AndrewSN> xzilla: of course, nothing is stopping you passing that
un-displayable timestamp value around once you got it in from
anywhere
17:12 < xzilla> AndrewSN: right

--
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL