Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> I have been observing a case where the row count estimation for LIKE 'foo' is
> (much) higher than for LIKE 'foo%', the rest of the query being the same.
> This is a special case of the estimation for equality being higher than for a
> range query that includes the value used in the equality.
Not really --- LIKE estimation is only weakly related to range
estimation.
Relevant questions here include exactly which PG version is in use and
what's the database encoding/locale. If it's not C locale, the fixes
I made in selfuncs.c during November might be relevant.
regards, tom lane