3.table_open_cache_instances The number of open tables cache instances. To improve scalability by reducing contention among sessions, the open tables cache can be partitioned into several smaller cache instances of size table_open_cache / table_open_cache_instances . A session needs to lock only...
the open tables cache can be partitioned into several smaller cache instances of size table_open_cache / table_open_cache_instances . A session needs to lock only one instance to access it for DML statements. This segments cache access among instances, permitting higher performance...
the open tables cache can be partitioned into several smaller cache instances of size table_open_cache / table_open_cache_instances . A session needs to lock only one instance to access it for DML statements. This segments cache access among instances, permitting higher performance...
void adjust_table_cache_size(ulong requested_open_files) limit=max((requested_open_files - 10 - max_connections) / 2, TABLE_OPEN_CACHE_MIN); if (limit { sql_print_warning("Changed limits: table_open_cache: %lu (requested%lu)",limit, table_cache_size); table_cache_size= limit; } 对...
本文根据我自己的一点经验,讨论了Mysql服务器优化中两个非常重要的参数,分别是table_cache,key_buffer_size。 table_cache指示表高速缓存的大小。当Mysql访问一个表时,如果在Mysql表缓冲区中还有空间,那么这个表就被打开并放入表缓冲区,这样做的好处是可以更快速地访问表中的内容。一般来说,可以通过查看数据库运行峰...
adjust_table_cache_size(*requested_open_files); adjust_table_def_size(); } 由于这四个设置函数存在严格的顺序调用关系,下文将依次对各个函数进行拆分说明。 1、open_files_limit 该参数作用为限定了MySQL实例进程能打开的文件描述符最大值。关于该参数设置函数的声明: ...
query_cache_size = 20M #缓存大小 query_cache_type = ON #开启缓存 table_cache=256 #用于限制缓存表的最大数目,如果当前已经缓存的表未达到table_cache,则会将新表添加进来;若已经达到此值,MySQL将根据缓存表的最后查询时间、查询率等规则释放之前的缓存 ...
Alter table tableName engine =engineName 备注:设置完后把以下几个开启: # Uncomment the following if you are using InnoDB tables innodb_data_home_dir = /var/lib/mysql #innodb_data_file_path = ibdata1:1024M;ibdata2:10M:autoextend(要注释掉,否则会创建一个新的把原来的替换的。) ...
由于该参数首先被设置,所以这部分计算逻辑所取用的变量均来自配置文件中的设置值(源码中的table_cache_size对应配置文件中的table_open_cache),根据计算后得出的limit_1,2,3将取最大值存放在变量request_open_files中。 PS:此处需注意的是,request_open_files和requested_open_files是不同的。