系統(tǒng)性能相關(guān)的MySQL變量

Memory-Related Variables
    內(nèi)存相關(guān)變量
    These server variables control the amount of memory allocated to the various buffers and caches within MySQL.
    以下這些服務(wù)器變量控制這MySQL分配給各種緩沖或者換緩存的內(nèi)存總數(shù)。
    join_buffer_size
    (PER SESSION) Controls the amount of memory allocated to perform joins on tables that have no keys which can be used to perform a condition filter. Allocated for each table joined without necessary filter conditions
    (會(huì)話變量) 控制在對(duì)沒有索引的表連接時(shí)分配的內(nèi)存總數(shù)，它可以用做條件過濾器。為連接中的每個(gè)表分配而無需必要的過濾條件。
    key_buffer_size
    (GLOBAL) (MyISAM-only) Controls the amount of memory allocated to the MyISAM index key cache
    (全局變量) (只針對(duì)MyISAM表) 空置分配給MyISAM索引緩存的內(nèi)存總數(shù)。
    innodb_buffer_pool_size
    (GLOBAL) (InnoDB-only) Controls the amount of memory allocated to the InnoDB cache containing both clustered data and secondary index pages
    (全局變量) (只針對(duì)Innodb) 控制分配給包括集群數(shù)據(jù)以及次要索引頁的Innodb緩存的內(nèi)存總數(shù)。
    innodb_additional_mem_pool_size
    (GLOBAL) (InnoDB-only) Controls the amount of memory allocated to the buffer storing the InnoDB internal data dictionary
    (全局變量) (只針對(duì)Innodb) 控制分配給對(duì)Innodb內(nèi)部數(shù)據(jù)字典進(jìn)行排序所需的緩沖。
    innodb_log_buffer_size
    (GLOBAL) (InnoDB-only) Controls the amount of memory allocated to the buffer storing InnoDB write-ahead log entries
    (全局變量) (只針對(duì)Innodb) 控制分配給對(duì)Innodb存儲(chǔ)提前寫日志記錄所需的緩沖。
    query_cache_size
    (GLOBAL) Controls the amount of memory allocated to the Query Cache
    (全局變量) 控制分配給查詢緩存的內(nèi)存總量。
    read_buffer_size
    (PER SESSION) Controls the amount of memory allocated to the connecting thread in order to process a table scan
    (會(huì)話變量) 控制分配給處理掃描表的連接線程內(nèi)存總數(shù)。
    read_rnd_buffer_size
    (PER SESSION) Controls the amount of memory allocated to the buffer used to read previously sorted results