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(at)avior(dot)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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