Kovacs Zoltan <kovacsz(at)pc10(dot)radnoti-szeged(dot)sulinet(dot)hu> writes:
> It means that the 21st line of the result is problematic, because writing
> 20 instead of 21 I got no problem.
I think not. The current implementation of LIMIT fetches one more row
than is really needed, IIRC.
regards, tom lane