Re: Regression in IN( field, field, field ) performance

Decibel! <decibel@decibel.org> writes:
> On Oct 21, 2008, at 12:06 PM, Tom Lane wrote:
>> "Jim 'Decibel!' Nasby" <jnasby@cashnetusa.com> writes:
>>> Filter: ('xxxxxxxxxxx'::text = ANY ((ARRAY[home_phone, mobile_phone,
>>> work_phone])::text[]))
>> 
> Which means automatic seqscan.
>> 
>> It means no such thing.

> It won't use an index scan on this query while it's in that form  
> (even with enable_seqscan=off), but if I change it to a bunch of OR'd  
> conditions it will switch to bitmap scans.

Works fine for me, eg

regression=# explain select * from tenk1 a, tenk1 b where
regression-# b.unique2 = any(array[a.unique1,a.ten,a.hundred]);                                   QUERY PLAN
                      
 
--------------------------------------------------------------------------------
--Nested Loop  (cost=0.79..49047.50 rows=29997 width=488)  ->  Seq Scan on tenk1 a  (cost=0.00..458.00 rows=10000
width=244) ->  Bitmap Heap Scan on tenk1 b  (cost=0.79..4.82 rows=3 width=244)        Recheck Cond: (b.unique2 = ANY
(ARRAY[a.unique1,a.ten, a.hundred]))        ->  Bitmap Index Scan on tenk1_unique2  (cost=0.00..0.79 rows=3 width=0
 
)              Index Cond: (b.unique2 = ANY (ARRAY[a.unique1, a.ten, a.hundred])
)
(6 rows)

You'll need to provide a concrete test case if you think there's
something broken here.
        regards, tom lane