Re: Optimizing queries

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If subquerys are not working I think you should try to create a view
with the subquery.

Maybe it will work.

Patrice Beliveau wrote:
> Tom Lane wrote:
>> Patrice Beliveau <pbeliveau@avior.ca> writes:
>>
>>>>> SELECT * FROM TABLE
>>>>> WHERE TABLE.COLUMN1=something
>>>>> AND TABLE.COLUMN2=somethingelse
>>>>> AND function(TABLE.COLUMN3,TABLE.COLUMN4) > 0;
>>>>>
>>
>>
>>> I find out that the function process every row even if the row should
>>> be rejected as per the first or the second condition.
>>> ... I'm using version 8.1.3
>>>
>>
>> PG 8.1 will not reorder WHERE clauses for a single table unless it has
>> some specific reason to do so (and AFAICT no version back to 7.0 or so
>> has done so either...)  So there's something you are not telling us that
>> is relevant.  Let's see the exact table schema (psql \d output is good),
>> the exact query, and EXPLAIN output for that query.
>>
>>             regards, tom lane
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 9: In versions below 8.0, the planner will ignore your desire to
>>        choose an index scan if your joining column's datatypes do not
>>        match
>>
>>
>>
> Hi,
>
> here is my query, and the query plan that result
>
> explain select * from (
>   select * from sales_order_delivery
>       where sales_order_id in (
>               select sales_order_id from sales_order
>               where closed=false
>       )
> ) as a where outstandingorder(sales_order_id, sales_order_item,
> date_due) > 0;
>
>
>                                                      QUERY PLAN
>
----------------------------------------------------------------------------------------------------------------------
>
> Hash IN Join  (cost=498.89..8348.38 rows=34612 width=262)
>   Hash Cond: (("outer".sales_order_id)::text =
> ("inner".sales_order_id)::text)
>   ->  Seq Scan on sales_order_delivery  (cost=0.00..6465.03 rows=69223
> width=262)
>         Filter: (outstandingorder((sales_order_id)::text,
> (sales_order_item)::text, date_due) > 0::double precision)
>   ->  Hash  (cost=484.90..484.90 rows=5595 width=32)
>         ->  Seq Scan on sales_order  (cost=0.00..484.90 rows=5595 width=32)
>               Filter: (NOT closed)
> (7 rows)
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
>               http://www.postgresql.org/docs/faq
>
>

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