Kostas Papadopoulos <kostas@methodosit.com.cy> writes:
> I cannot see how it can be configuration since the two databases are in the same
> Postgres instance.
There is such a thing as ALTER DATABASE ... SET to install different
settings at the per-database level.
In general, the answer to your question is that the databases are
*not* identical. You just haven't figured out how yet. I'm wondering
if it has something to do with the dump/reload having compacted out
bloat in the tables or indexes, causing cost estimates to change.
regards, tom lane