Taijicoder Wiki

本页面只读。您可以查看源文件，但不能更改它。如果您觉得这是系统错误，请联系管理员。
## 移除Wordpress的Revision

wordpress的的revision功能 会产生慢查询
```
Count: 637684  Time=19.43s (12387815s)  Lock=0.04s (23212s)  Rows_sent=6.0 (3825972), Rows_examined=129548.8 (82611224762), fagaodata[fagaodata]@localhost
  # Rows_affected: N
  SET timestamp=N;
  SELECT SQL_CALC_FOUND_ROWS  wp_posts.ID FROM wp_posts  LEFT JOIN wp_term_relationships ON (wp_posts.ID = wp_term_relationships.object_id) WHERE N=N  AND wp_posts.ID NOT IN (N) AND (
  wp_term_relationships.term_taxonomy_id IN (N)
  ) AND wp_posts.post_type = 'S' AND (wp_posts.post_status = 'S') GROUP BY wp_posts.ID ORDER BY wp_posts.post_date DESC LIMIT N, N
```

如果需要去除这个慢查询，并且你的网站不依赖revisions功能。可以做如下操作

### 1. 禁止掉revision

在wp-config.php中添加
```
define ('WP_POST_REVISIONS', 0); 
```

### 2. 删除旧的revision数据

在mysql中执行
```
DELETE a,b,c
FROM wp_posts a
LEFT JOIN wp_term_relationships b ON (a.ID = b.object_id)
LEFT JOIN wp_postmeta c ON (a.ID = c.post_id)
WHERE a.post_type = 'revision'
```

### 3. 如果你还想提高wordpress的运行内存的话

在wp-config.php 的开头添加

```
define('WP_MEMORY_LIMIT', '512M'); //你可以改成你想要的大小
```

[参考资料：Wordpress 移除revision，提高性能](https://serverfault.com/questions/217008/how-do-i-optimize-a-high-traffic-wordpress-website/217052#217052)