Question

糟糕的搜索查询导致我们的网站崩溃。写入计数每个子类别的人，然后将它们加在一起以获得主要类别的总数。对于分页Next，Last，Pages，然后使用JOIN / INNER JOIN（该页面的所有产品）编写查询。它创造了太多的步骤，从而减慢了所有的速度，直到它超时。救命！

查询摘要：

SELECT COUNT(DISTINCT node.nid) AS cnt FROM 
content_type_product cp 
LEFT JOIN node node ON node.nid = cp.nid 
LEFT JOIN uc_products uc_products ON node.nid = uc_products.nid 
LEFT JOIN users users ON users.uid = node.uid 
LEFT JOIN files ON files.fid = cp.field_product_image_1_value 
LEFT JOIN content_type_product_tags ct ON ct.field_product_product_id_value = cp.nid 
WHERE 
    (
    node.status <> N
    ) 
AND 
    (
    ct.field_product_tag_id_value = N
    ) 
AND 
    (
    cp.field_deleted_value <> N
    ) 
AND 
    (
    cp.field_stock_level_value > N
    ) 
AND EXISTS 
    (
    SELECT scp.nid FROM content_type_store scp 
    LEFT JOIN node snode ON snode.nid = scp.nid 
    LEFT JOIN users susers ON susers.uid = snode.uid 
    WHERE susers.name = users.name 
        AND scp.field_shop_activated_value = 'S' 
        AND scp.field_shop_suspended_value = 'S') 
ORDER BY cp.field_product_last_changed_value DESC;

查询示例：

SELECT count(Distinct node.nid) as cnt 
FROM content_type_product cp 
LEFT JOIN node node ON node.nid = cp.nid 
LEFT JOIN uc_products uc_products ON node.nid = uc_products.nid 
LEFT JOIN users users ON users.uid = node.uid 
LEFT JOIN files ON files.fid = cp.field_product_image_1_value 
LEFT JOIN content_type_product_tags ct ON ct.field_product_product_id_value = cp.nid
WHERE 
    (
    node.status <> 0
    ) 
    AND 
        (
        ct.field_product_tag_id_value = 478
        ) 
    AND 
        (
        cp.field_deleted_value <> 1
        ) 
    AND 
        (
        cp.field_stock_level_value > 0
        ) 
    AND EXISTS 
        (
        SELECT scp.nid FROM content_type_store scp 
        LEFT JOIN node snode on snode.nid = scp.nid 
        LEFT JOIN users susers on susers.uid = snode.uid 
        WHERE susers.name = users.name 
            AND scp.field_shop_activated_value = '1' 
            AND scp.field_shop_suspended_value = '0'
        ) 
    ORDER BY cp.field_product_last_changed_value DESC

Answer 1

在主表和连接表中添加索引将固定您的查询。

Answer 2

以下步骤需要遵循以避免慢查询

首先从节点开始，而不是从内容表开始。
对于与vid而非nid
无需在查询中使用distinct和group by。如果您使用它，您的查询有一些加入问题。

SELECT count(Distinct node.nid) as cnt 
FROM node node 
LEFT JOIN content_type_product cp ON cp.vid = node.vid 
LEFT JOIN uc_products uc_products ON node.vid = uc_products.vid 
LEFT JOIN users users ON users.uid = node.uid 
LEFT JOIN files ON files.fid = cp.field_product_image_1_value 
LEFT JOIN content_type_product_tags ct ON ct.field_product_product_id_value = cp.vid
WHERE 
    (
    node.status <> 0
    ) 
    AND 
        (
        ct.field_product_tag_id_value = 478
        ) 
    AND 
        (
        cp.field_deleted_value <> 1
        ) 
    AND 
        (
        cp.field_stock_level_value > 0
        ) 
    AND EXISTS 
        (
        SELECT scp.nid FROM content_type_store scp 
        LEFT JOIN node snode on snode.nid = scp.nid 
        LEFT JOIN users susers on susers.uid = snode.uid 
        WHERE susers.name = users.name 
            AND scp.field_shop_activated_value = '1' 
            AND scp.field_shop_suspended_value = '0'
        ) 
    ORDER BY cp.field_product_last_changed_value DESC

慢搜索查询 - 编码错误，（LEFT JOIN）

2 个答案: