我有一个群集的WordPress webapp，它使用一个由六个节点组成的Memcached群集来存储WordPress的对象缓存，但我似乎遇到了某种零星的Memcached设置/替换循环或缓存踩踏，偶尔会导致单个Memcached集群中的节点完全使Memcached和数据库网络链接饱和。
设置/替换循环或踩踏似乎是由于尝试“添加”WordPress“wp_：options：alloptions”键的大量尝试引起的，Memcached使用NOT_STORED回复所有这些特定查询。与此同时，大多数MySQL查询都是这样的：
SELECT option_name, option_value
FROM wp_options
WHERE autoload = 'yes'
我对Memcached Object Cache插件（http://wordpress.org/extend/plugins/memcached/）所做的唯一更改是默认的到期设置。
#var $default_expiration = 0; //original
var $default_expiration = 1800;
到目前为止，我已经能够通过增加Memcached守护程序最大连接限制来缓解此问题。我还将数据库存储引擎从MyISAM更改为InnoDB，并将APC shm_size从128M增加到1536M。
对象缓存是否设置/替换循环或踩踏不可避免，还是我当前设置的结果？
环境：
Memcached 1.4.14-1
PORT="11211"
USER="nobody"
MAXCONN="10240"
CACHESIZE="4096"
OPTIONS=""
PHP 5.3.28
memcache版本3.0.8 memcache support =＆gt;启用 memcache.allow_failover =＆gt; 0 =＆gt; 0 memcache.chunk_size =＆gt; 32768 =＆gt; 32768 memcache.compress_threshold =＆gt; 20000 =＆gt; 20000 memcache.default_port =＆gt; 11211 =＆gt; 11211 memcache.hash_function =＆gt; fnv =＆gt; FNV memcache.hash_strategy =＆gt;一致=＆gt;一贯 memcache.lock_timeout =＆gt; 15 =＆gt; 15 memcache.max_failover_attempts =＆gt; 20 =＆gt; 20 memcache.protocol =＆gt; ascii =＆gt; ASCII memcache.redundancy =＆gt; 1 =＆gt; 1 memcache.session_redundancy =＆gt; 2 =＆gt; 2 已注册的保存处理程序=＆gt;文件用户memcache
APC Version =＆gt; 3.1.9 APC调试=＆gt;残 MMAP支持=＆gt;启用 MMAP文件掩码=＆gt; 锁定类型=＆gt; pthread互斥锁 序列化支持=＆gt;破碎 指令=＆gt;本地值=＆gt;掌握价值 apc.cache_by_default =＆gt; On =＆gt;上 apc.canonicalize =＆gt; On =＆gt;上 apc.coredump_unmap =＆gt; Off =＆gt;离 apc.enable_cli =＆gt; Off =＆gt;离 apc.enabled =＆gt; On =＆gt;上 apc.file_md5 =＆gt; Off =＆gt;离 apc.file_update_protection =＆gt; 2 =＆gt; 2 apc.filters =＆gt;没有价值=＆gt;没有价值 apc.gc_ttl =＆gt; 3600 =＆gt; 3600 apc.include_once_override =＆gt; Off =＆gt;离 apc.lazy_classes =＆gt; Off =＆gt;离 apc.lazy_functions =＆gt; Off =＆gt;离 apc.max_file_size =＆gt; 1M =＆gt; 1M apc.mmap_file_mask =＆gt;没有价值=＆gt;没有价值 apc.num_files_hint =＆gt; 1000 =＆gt; 1000 apc.preload_path =＆gt;没有价值=＆gt;没有价值 apc.report_autofilter =＆gt; Off =＆gt;离 apc.rfc1867 =＆gt; Off =＆gt;离 apc.rfc1867_freq =＆gt; 0 =＆gt; 0 apc.rfc1867_name =＆gt; APC_UPLOAD_PROGRESS =＆gt; APC_UPLOAD_PROGRESS apc.rfc1867_prefix =＆gt; upload_ =＆gt; upload_ apc.rfc1867_ttl =＆gt; 3600 =＆gt; 3600 apc.serializer =＆gt;默认=＆gt;默认 apc.shm_segments =＆gt; 1 =＆gt; 1 apc.shm_size =＆gt; 1536M =＆gt; 1536M apc.slam_defense =＆gt; On =＆gt;上 apc.stat =＆gt; On =＆gt;上 apc.stat_ctime =＆gt; Off =＆gt;离 apc.ttl =＆gt; 0 =＆gt; 0 apc.use_request_time =＆gt; On =＆gt;上 apc.user_entries_hint =＆gt; 4096 =＆gt; 4096 apc.user_ttl =＆gt; 0 =＆gt; 0 apc.write_lock =＆gt; On =＆gt;上
答案 0 :(得分：0)