如果我将生产数据库导出到.sql文件然后将其导入本地计算机，那么在生产数据库上运行速度非常快（90毫秒）的完全相同的查询在本地运行速度非常慢（100秒或更长）。 / p>
制作mysql版本：5.7.18 本地mysql版本：5.7.21
我检查过，看起来两个数据库中的所有索引都是相同的。唯一的区别是基数值在索引上是不同的。这会有所作为吗？
以下是一个缓慢的查询示例：
SELECT DISTINCT v0.`id`
FROM `visibility__slugs` AS v0
INNER JOIN `visibility__business_type_slug` AS v5 ON v5.`slug_id` = v0.`id`
INNER JOIN `visibility__business_types` AS v1 ON (v5.`business_type_id` = v1.`id`) AND (v1.`type_name` != 'Other')
INNER JOIN `visibility__business_type_page` AS v6 ON v6.`business_type_id` = v1.`id`
INNER JOIN `visibility__pages` AS v2 ON v6.`page_id` = v2.`id`
INNER JOIN `visibility__page_postal_code` AS v7 ON v7.`page_id` = v2.`id`
INNER JOIN `visibility__postal_codes` AS v3 ON v7.`postal_code` = v3.`postal_code`
WHERE (v2.`is_live`)
这是EXPLAIN
1 SIMPLE v0 NULL index PRIMARY,visibility__slugs_slug_unique visibility__slugs_slug_unique 767 NULL 1 100.00 Using index; Using temporary
1 SIMPLE v3 NULL index visibility__postal_codes_postal_code_unique,visibility__postal_codes_postal_code_index visibility__postal_codes_postal_code_index 767 NULL 1 100.00 Using index; Distinct; Using join buffer (Block Nested Loop)
1 SIMPLE v5 NULL ref visibility__business_type_slug_slug_id_business_type_id_unique,visibility__business_type_slug_slug_id_index,visibility__business_type_slug_business_type_id_index visibility__business_type_slug_slug_id_index 4 zipbooks_development.v0.id 1 100.00 Using index; Distinct
1 SIMPLE v1 NULL eq_ref PRIMARY PRIMARY 4 zipbooks_development.v5.business_type_id 1 90.00 Using where; Distinct
1 SIMPLE v6 NULL ref visibility__business_type_page_page_id_business_type_id_unique,visibility__business_type_page_page_id_index,visibility__business_type_page_business_type_id_index visibility__business_type_page_business_type_id_index 4 zipbooks_development.v5.business_type_id 15 100.00 Using index; Distinct
1 SIMPLE v2 NULL eq_ref PRIMARY PRIMARY 4 zipbooks_development.v6.page_id 1 90.00 Using where; Distinct
1 SIMPLE v7 NULL eq_ref visibility__page_postal_code_page_id_postal_code_unique,visibility__page_postal_code_page_id_index,visibility__page_postal_code_postal_code_index visibility__page_postal_code_page_id_postal_code_unique 771 zipbooks_development.v6.page_id,zipbooks_development.v3.postal_code 1 100.00 Using index; Distinct
这是慢查询日志：
Time Id Command Argument# Time: 2018-02-14T18:12:40.968206Z
# User@Host: root[root] @ localhost [127.0.0.1] Id: 2
# Query_time: 191.781505 Lock_time: 0.000142 Rows_sent: 0 Rows_examined: 183768270
SET timestamp=1518631960;
SELECT DISTINCT v0.`id`
FROM `visibility__slugs` AS v0
INNER JOIN `visibility__business_type_slug` AS v5 ON v5.`slug_id` = v0.`id`
INNER JOIN `visibility__business_types` AS v1 ON (v5.`business_type_id` = v1.`id`) AND (v1.`type_name` != 'Other')
INNER JOIN `visibility__business_type_page` AS v6 ON v6.`business_type_id` = v1.`id`
INNER JOIN `visibility__pages` AS v2 ON v6.`page_id` = v2.`id`
INNER JOIN `visibility__page_postal_code` AS v7 ON v7.`page_id` = v2.`id`
INNER JOIN `visibility__postal_codes` AS v3 ON v7.`postal_code` = v3.`postal_code`
WHERE (v2.`is_live`);
有趣的是，它有时会起作用。有时我导入备份，查询和生产一样快。我没有看到它在工作时和导入后查询非常慢之间的模式，但这是值得注意的。它可能与我们使用--single-transaction --quick转储生产有关吗？
有人能想到我可以尝试的一些事情吗？配置值？这可能有什么问题？
答案 0 :(得分：1)
我的索引已损坏。我找到了违规的桌子并跑了
ALTER TABLE visibility__postal_codes ENGINE = InnoDB;
重建索引，现在已经修复了。