Re: simple query with radically different plan after 9.0 -> 9.2 upgrade

Now, the only way to get to a zero selectivity estimate for var = const
is if the planner believes that the pg_stats most-common-values list
for the column is complete, and the constant is nowhere in the list.
So one plausible explanation for the change in behavior is that you
jacked up the statistics target for the date column enough so that
it includes all of the date values you keep in that column.  

Am I right
in guessing that you drop old data from this table?  How far back?