Re: Composite index planner issues Was: Re: Constraint exclusion oddity with composite index

"Joshua D. Drake" <jd@commandprompt.com> writes:
>> I guess where I got confused is:
>> 
>> http://www.postgresql.org/docs/8.1/static/indexes-multicolumn.html
>> 
>> And explicitly:
>> 
>> A multicolumn B-tree index can be used with query conditions that 
>> involve any subset of the index's columns, but the index is most 
>> efficient when there are constraints on the leading (leftmost) columns.

> Considering the paragraph from the documentation above, should we change 
> the documentation?

That statement seems perfectly accurate to me.
        regards, tom lane