Optimize this query selecting associated configurable products

Question

Given a configurable product ID (45535), I'm getting the IDs of other configurable products that are linked via a simple product. I'm trying to see if this query can be made faster.. Is it possible to make this query any faster?

SELECT l2.`parent_id`
FROM catalog_product_super_link AS l
    INNER JOIN catalog_product_super_link AS l2
        ON l.`product_id` = l2.`product_id`
WHERE l.`parent_id` = 45535 AND l2.`parent_id` != 45535 GROUP BY l2.`parent_id`;

When I run EXPLAIN, I get the following

id  select_type table   type    possible_keys   key key_len ref rows    Extra
1   SIMPLE  l   ref UNQ_CATALOG_PRODUCT_SUPER_LINK_PRODUCT_ID_PARENT_ID,IDX_CATALOG_PRODUCT_SUPER_LINK_PARENT_ID,IDX_CATALOG_PRODUCT_SUPER_LINK_PRODUCT_ID  IDX_CATALOG_PRODUCT_SUPER_LINK_PARENT_ID    4   const   30  Using temporary; Using filesort
1   SIMPLE  l2  ref UNQ_CATALOG_PRODUCT_SUPER_LINK_PRODUCT_ID_PARENT_ID,IDX_CATALOG_PRODUCT_SUPER_LINK_PARENT_ID,IDX_CATALOG_PRODUCT_SUPER_LINK_PRODUCT_ID  UNQ_CATALOG_PRODUCT_SUPER_LINK_PRODUCT_ID_PARENT_ID 4   test_db.l.product_id    1   Using where; Using index

Table catalog_product_super_link has about 42K rows.

Answer 1

I usually avoid direct SQL queries. Hopefully you're building some sort of reporting mechanism to generate some business intelligence. Please don't build a feature for your store based on the following recommendations.

In this case you probably would do well to create an in-memory temporary table which is populated by all configurable links that have 45535 as its' parent.

CREATE TABLE cpsl_memory ENGINE=MEMORY
SELECT * FROM catalog_product_super_link WHERE parent_id = 45535;

And then select from this table:

SELECT product_id FROM cpsl_memory 
WHERE parent_id != 45535
GROUP BY product_id;

The GROUP BY here collapses duplicates - you could probably use DISTINCT as well. Of course you want to tear down the temporary table afterward:

DROP TABLE cpsl_memory;

Alternative methods:

Same technique, different methods. Disclaimer: these may not be faster.

Local vars:

SET @instmt = (SELECT GROUP_CONCAT(DISTINCT product_id SEPARATOR ',') FROM catalog_product_super_link WHERE parent_id=45535);
SELECT * FROM catalog_product_super_link WHERE parent_id NOT IN (@instmt);

Subquery:

SELECT * FROM catalog_product_super_link cpsl
WHERE cpsl.parent_id <> 45535
AND cpsl.product_id IN (
    SELECT product_id FROM catalog_product_super_link cpslsq WHERE parent_id=45535;
)

Disclaimer:

Query optimization is probably off-topic for Magento.SE - but I spent the better part of 1.0-1.3CE creatively optimizing sales reports for EAV I thought I'd help you out. I'm not a DBA.

In absence of having some sample data from you I've cobbled together the above, largely untested, as to guide you into other methods (besides the self-join) to accomplish a similar result.