> The rowcount estimates from 9.2 seem greatly different from the 8.4 plan.
> Did you remember to ANALYZE all the tables after migrating? Maybe there
> were some table-specific statistics targets that you forgot to transfer
No, I did not. Honestly I though everything would be transfered with a
dump/restore procedure. Unfortunatly running ANALYZE VERBOSE on all
involved tables did not really improve anything.
> In any case, the 9.2 plan looks like garbage-in-garbage-out to
> me :-( ... without estimates at least a little closer to reality, the
> planner is unlikely to do anything very sane.
> (BTW, I wonder why you are moving only to 9.2 and not something more
Well, 9.2.15 is what comes bundled with RHEL 7, so I decided to go with
that to avoid dependency issues. But I could install a more fresh
version from scratch if that would solve my problem.