js(at)deriva(dot)de writes:
> It's Version 8.3.
> Both columns are of a user defined datatype which is a varchar(12)
> with a special check.
You mean a DOMAIN, or you mean a special datatype with custom C code?
If the latter, I'd suspect the C code. 8.3 has more stringent coding
rules for variable-length datatypes than prior releases did.
regards, tom lane