Re: best way to fetch next/prev record based on index - Mailing list pgsql-performance

"Merlin Moncure" <merlin.moncure@rcsonline.com> writes:
> So, for a table t with a three part key over columns a,b,c, the query to
> read the next value from t for given values a1, b1, c1 is

> select * from t where
>     a >= a1 and
>      (a >  a1 or b >= b1) and
>      (a >  a1 or b > b1 or c > c1)

> In about 95% of cases, the planner correctly selects the index t(a,b,c)
> and uses it.

I'm surprised it's that good.  Why not do

    select * from t where a >= a1 and b >= b1 and c >= c1
    order by a,b,c
    limit 1 offset 1;

which has a much more obvious translation to an indexscan.

            regards, tom lane