好奇怪的问题，付费求解决。

情况是这样。
wordpress 对象缓存 查询缓慢。
首先，我停用所有插件，切换到wordpress默认主题。
使用memcached对象缓存插件，php执行时间长达22秒才完成。

使用apcu对象缓存插件，PHP执行时间长达3秒完成。
使用redis对象缓存插件倒是正常了，但是使用时间一长也会出现超长php执行时间。
这个时间一长可能是1天，可能是1星期。

一个页面需要长达十几几十秒才能完成就导致CPU直接100%。

我在服务器上安装的其他wordpress博客均无此问题。

下面是PHP慢查询日志

[31-May-2017 01:40:45] [pool www] pid 20573
script_filename = /data/wwwroot/wordpress/index.php
[0x00007ff4f0613240] add() /data/wwwroot/wordpress/wp-content/object-cache.php:900
[0x00007ff4f0613150] add() /data/wwwroot/wordpress/wp-content/object-cache.php:18
[0x00007ff4f06130a0] wp_cache_add() /data/wwwroot/wordpress/wp-includes/option.php:197
[0x00007ff4f0612fd0] wp_load_alloptions() /data/wwwroot/wordpress/wp-includes/option.php:83
[0x00007ff4f0612eb0] get_option() /data/wwwroot/wordpress/wp-includes/theme.php:293
[0x00007ff4f0612d90] get_template() /data/wwwroot/wordpress/wp-includes/theme.php:328
[0x00007ff4f0612c00] get_template_directory_uri() /data/wwwroot/wordpress/wp-content/themes/twentyfifteen/functions.php:263
[0x00007ff4f0612aa0] twentyfifteen_scripts() /data/wwwroot/acg18/wp-includes/class-wp-hook.php:298
[0x00007ff4f06129c0] apply_filters() /data/wwwroot/wordpress/wp-includes/class-wp-hook.php:323
[0x00007ff4f0612950] do_action() /data/wwwroot/wordpress/wp-includes/plugin.php:453
[0x00007ff4f0612850] do_action() /data/wwwroot/wordpress/wp-includes/script-loader.php:1221
[0x00007ff4f06127f0] wp_enqueue_scripts() /data/wwwroot/wordpress/wp-includes/class-wp-hook.php:298
[0x00007ff4f0612710] apply_filters() /data/wwwroot/wordpress/wp-includes/class-wp-hook.php:323
[0x00007ff4f06126a0] do_action() /data/wwwroot/wordpress/wp-includes/plugin.php:453
[0x00007ff4f06125a0] do_action() /data/wwwroot/wordpress/wp-includes/general-template.php:2574
[0x00007ff4f0612550] wp_head() /data/wwwroot/wordpress/wp-content/themes/twentyfifteen/header.php:21
[0x00007ff4f06124e0] [INCLUDE_OR_EVAL]() /data/wwwroot/wordpress/wp-includes/template.php:684
[0x00007ff4f0612390] load_template() /data/wwwroot/wordpress/wp-includes/template.php:643
[0x00007ff4f06122b0] locate_template() /data/wwwroot/wordpress/wp-includes/general-template.php:45
[0x00007ff4f0612210] get_header() /data/wwwroot/wordpress/wp-content/themes/twentyfifteen/404.php:10