解决更新后的查询结果仍然是旧值的问题--gunicorn

最新推荐文章于 2025-08-15 09:35:33 发布

原创最新推荐文章于 2025-08-15 09:35:33 发布 · 244 阅读

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今天遇到了一个现象：前端更新完一个值后，立刻调用列表接口，得到的数据是更新前的旧数据。

排查了数据库的隔离级别，是 READ COMMITTED，没问题，不会导致脏读。后来把项目的debug级别日志全开启，日志如下：

# 列表的查询sql
[2025-05-07 11:23:55] [DEBUG] [django.db.backends:151] (0.000) SELECT COUNT(*) AS `__count` FROM `zz_certification` WHERE `zz_certification`.`stat` = 1; args=(True,); alias=default
[2025-05-07 11:23:55] [DEBUG] [django.db.backends:151] (0.001) SELECT `zz_certification`.`id`, `zz_certification`.`created`, `zz_certification`.`updated`, `zz_certification`.`stat`, `zz_certification`.`name`, `zz_certification`.`cpu`, `zz_certification`.`server`, `zz_certification`.`os`, `zz_certification`.`app`, `zz_certification`.`certification_date`, `zz_certification`.`expiration_date`, `zz_certification`.`pdf_file` FROM `zz_certification` WHERE `zz_certification`.`stat` = 1 ORDER BY `zz_certification`.`id` DESC LIMIT 2; args=(True,); alias=default
# 更新数据的执行sql
[2025-05-07 11:23:55] [DEBUG] [django.db.backends:151] (0.002) UPDATE `zz_certification` SET `created` = '2025-04-30 09:02:50.702621', `updated` = '2025-05-07 03:23:55.867630', `stat` = 1, `name` = 102, `cpu` = 2, `server` = 7, `os` = 4, `app` = 'tttttttr56', `certification_date` = '2025-04-15', `expiration_date` = '2025-05-11', `pdf_file` = '' WHERE `zz_certification`.`id` = 3; args=('2025-04-30 09:02:50.702621', '2025-05-07 03:23:55.867630', True, 102, 2, 7, 4, 'tttttttr56', '2025-04-15', '2025-05-11', '', 3); alias=default

从这两个sql的先后顺序可以看到，更新数据的sql 晚于列表的查询sql。可我的操作明明是先更新数据，后查询列表数据。

解决：
我想到了我的项目服务层–gunicorn，问题的原因也确实是它。gunicorn的配置文件里有一项：worker_class = 'gevent' 这里我设置的是 gevent，当初是为了高I/O性能，但需要考虑实际的使用场景，下面是各种情况的比较：
在这里插入图片描述
我改成sync之后就正常了，sql执行的顺序没有问题了。

# 更新数据的执行sql
[2025-05-07 11:39:24] [DEBUG] [django.db.backends:151] (0.002) UPDATE `zz_certification` SET `created` = '2025-04-30 09:02:50.702621', `updated` = '2025-05-07 03:39:24.118264', `stat` = 1, `name` = 102, `cpu` = 2, `server` = 7, `os` = 4, `app` = 'tttttttr567', `certification_date` = '2025-04-15', `expiration_date` = '2025-05-11', `pdf_file` = '' WHERE `zz_certification`.`id` = 3; args=('2025-04-30 09:02:50.702621', '2025-05-07 03:39:24.118264', True, 102, 2, 7, 4, 'tttttttr567', '2025-04-15', '2025-05-11', '', 3); alias=default
# 列表的查询sql
[2025-05-07 11:39:24] [DEBUG] [django.db.backends:151] (0.001) 
                SELECT VERSION(),
                       @@sql_mode,
                       @@default_storage_engine,
                       @@sql_auto_is_null,
                       @@lower_case_table_names,
                       CONVERT_TZ('2001-01-01 01:00:00', 'UTC', 'UTC') IS NOT NULL
            ; args=None; alias=default
[2025-05-07 11:39:24] [DEBUG] [django.db.backends:151] (0.000) SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED; args=None; alias=default
[2025-05-07 11:39:24] [DEBUG] [django.db.backends:151] (0.001) SELECT COUNT(*) AS `__count` FROM `zz_certification` WHERE `zz_certification`.`stat` = 1; args=(True,); alias=default
[2025-05-07 11:39:24] [DEBUG] [django.db.backends:151] (0.001) SELECT `zz_certification`.`id`, `zz_certification`.`created`, `zz_certification`.`updated`, `zz_certification`.`stat`, `zz_certification`.`name`, `zz_certification`.`cpu`, `zz_certification`.`server`, `zz_certification`.`os`, `zz_certification`.`app`, `zz_certification`.`certification_date`, `zz_certification`.`expiration_date`, `zz_certification`.`pdf_file` FROM `zz_certification` WHERE `zz_certification`.`stat` = 1 ORDER BY `zz_certification`.`id` DESC LIMIT 2; args=(True,); alias=default