Re: Query Plan - Index Scan & Seq Scan

code data type is int2.

I am sorry that I did not mention the version number

I am using 7.4.7.

Thanks,
-Prasanth.

Tom Lane wrote:
> Prasanth <dbadmin(at)nqadmin(dot)com> writes:
>
>>A where condition I always use is shown below. This is bringing down the number
>>of rows from 6.5m to 1210. I have an index on code also. Even here it is going
>>for seq scan.
>
>
>>EXPLAIN ANALYZE SELECT count(*) fROM a where Code >2;
>> QUERY PLAN
>>-------------------------------------------------------------------------------------------------------------------------------
>> Aggregate (cost=141321.09..141321.09 rows=1 width=0) (actual
>>time=6454.063..6454.064 rows=1 loops=1)
>> -> Seq Scan on a (cost=0.00..141318.40 rows=1076 width=0) (actual
>>time=15.687..6453.292 rows=1210 loops=1)
>> Filter: (code > 2)
>> Total runtime: 6454.140 ms
>>(4 rows)
>
>
> I'm going to hazard a guess that "code" is not of type integer, and that
> you're using a pre-8.0 PG release. Cross-type comparisons are not
> indexable before 8.0, so you need to cast the integer constant 2 to
> whatever type "code" is.
>
> regards, tom lane
>
>