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Asked: 2026-06-04T03:25:01+00:00

How is it possible to have a good plan in EXPLAIN like below and

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How is it possible to have a good plan in EXPLAIN like below and have a slow query. With few rows, using index, no filesort.

The query is running in 9s. The main table has around 500k rows.

When I had 250k rows in that table, the query was running in < 1s.

Suggestions plz?

explain

Query (1. fields commented can be enabled according user choice. 2. Without FORCE INDEX I got 14s. 3. SQL_NO_CACHE I use to prevent false results):

    SELECT SQL_NO_CACHE
          p.property_id
        , lct.loc_city_name_pt
        , lc.loc_community_name_pt
        , lc.loc_community_image_num_default
        , lc.loc_community_gmap_longitude
        , lc.loc_community_gmap_latitude
    FROM property as p FORCE INDEX (ix_order_by_perf)
    INNER JOIN loc_community lc 
        ON lc.loc_community_id = p.property_loc_community_id
    INNER JOIN loc_city lct FORCE INDEX (loc_city_id)
        ON lct.loc_city_id = lc.loc_community_loc_city_id
    INNER JOIN property_attribute pa
        ON pa.property_attribute_property_id = p.property_id        
    WHERE p.property_published = 1
        AND (p.property_property_type_id = '1' AND p.property_property_type_sale_id = '1') 
        AND p.property_property_housing_id = '1' 
--      AND p.property_loc_community_id = '36'  
--      AND p.property_bedroom_id = '2'
--      AND p.property_price >= '50000' AND p.property_price <= '150000'
--      AND lct.loc_city_id = '1'
--      AND p.property_loc_subcommunity_id IN(7,8,12) 
    ORDER BY 
          p.property_featured DESC
        , p.property_ranking_date DESC
        , p.property_ranking_total DESC
    LIMIT 0, 15

Query Profile

query profile

The resultset always outputs 15 rows. But the table property and property_attribute has around 500k rows.

Thanks all,

Armando Miani

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1 Answer

  1. Editorial Team

    There’s a moment when your query will be optimized around a model which might not be anymore valid for a given need.

    A plan could be great but, even if the filters you are using in the where clause respect indexes definitions, it doesn’t mean the parser doesn’t parse may rows.

    What you have to analize is how determinating are your indexes. For instance, if there’s an index on “name, family name” in a “person” table, the performances are going to be poor if everybody has the same name and family name. The index is a real trap pulling down performances when it doesn’t manage to be enough describing a certain segment of your datasets.

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