Fine. The rest documentation says:" For now, the test only uses restriction clauses (those in restrictinfo_list). --Nels, Dec '92", however, I understand it as being overridden by the
followup, which is:"XXX as of 7.1, equivalence class info *is* available. Consider
improving this code as foreseen by Nels."
improving this code as foreseen by Nels."
Therefore, equivalence class should be detected and used for index selection... or anyone
could tell me if after 7.1 Postgresql has determined not to use equi-join for index selection...
On 1/16/06, Tom Lane <[EMAIL PROTECTED]> wrote:
uwcssa <[EMAIL PROTECTED]> writes:
> I am using postgres 8.1. In indxpath.c, it says " Note: if Postgres tried
> to optimize queries by forming equivalence
> classes over equi-joined attributes (i.e., if it recognized that
> aqualification such as "where
> a.b=3Dc.d and a.b=3D5" could make use of
> an index on c.d), then we could use that equivalence class info here with
> joininfo_list to do more complete tests for the usability
> of a partial index. ..... XXX as of 7.1, equivalence class info *is*
> available."
Are you deliberately ignoring the rest of the comment?
regards, tom lane
