Not sure if it helps, but it's apparently not a very rare thing. Quick analysis on data from explain.depesz.com showed that > 12% of plans with nested loop have such estimate.
Couple of examples: http://explain.depesz.com/s/Qm4 http://explain.depesz.com/s/qmW http://explain.depesz.com/s/qnG http://explain.depesz.com/s/QO http://explain.depesz.com/s/qov http://explain.depesz.com/s/qqb http://explain.depesz.com/s/QqF http://explain.depesz.com/s/qQO http://explain.depesz.com/s/qrI http://explain.depesz.com/s/QRK http://explain.depesz.com/s/QUX9 http://explain.depesz.com/s/QvN http://explain.depesz.com/s/QWL http://explain.depesz.com/s/r4F http://explain.depesz.com/s/R7q http://explain.depesz.com/s/r8 http://explain.depesz.com/s/R8 http://explain.depesz.com/s/RaB http://explain.depesz.com/s/RbV http://explain.depesz.com/s/Rc7 all these plans are public and not anonymized. depesz -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
