Hello all,

While testing Index scan,I found the following phonomenon.
 
	SELECT id from xxxxxx
	where id=10 or id=11;

is very fast.

But 
	SELECT id from xxxxxx
	where (id>=10 and id<=10)
	or (id>=11 and id<=11);

is very slow.
Why ?

The EXPLAIN(not verbose) output of both SQL are same 
except cost and size.

	NOTICE:  QUERY PLAN:

	Index Scan using xxxxxx_pkey, xxxxxx_pkey on xxxxxx 
	 (cost=1136.17 size=197 width=4)


It seems that (id>=..) is included in indexqual but (id<=.. )
is not.

Thanks.

Hiroshi Inoue
Inoue@tpf.co.jp

Fri, 19 Mar 1999 18:26:23 +0900
"Hiroshi Inoue" <Inoue@tpf.co.jp>
indexes with OR clauses is slow ?