Join on incompatible types

>>>>> "scott" == scott marlowe <scott.marlowe@ihs.com> writes:

[...]

  scott> Note here:

  scott> Merge Join (cost=1788.68..4735.71 rows=1 width=85) (actual
  scott> time=597.540..1340.526 rows=20153 loops=1) Merge Cond:
  scott> ("outer".id = "inner".id)

  scott> This estimate is WAY off.  Are both of those fields indexed
  scott> and analyzed?  Have you tried upping the statistics target on
  scott> those two fields?  I assume they are compatible types.

Should I understand that a join on incompatible types (such as integer
and varchar) may lead to bad performances ?

--
Laurent Martelli
laurent@aopsys.com                                Java Aspect Components
http://www.aopsys.com/                             http://jac.aopsys.com