While studying this I noticed a number of potential buffer overruns in
the 7.2.3 version of describeTableDetails(). They were mostly fixed
already in 7.3, and I just committed a fix for one more. However,
I do not believe that any of these overruns could have occurred in the
example you give, so there's still something fishy going on. On the
whole, I'd still bet that it's a 64-bit-platform issue. But where?
Good luck digging...
regards, tom lane