系統(tǒng)性能相關(guān)的MySQL變量

系統(tǒng)性能相關(guān)的MySQL變量 原文摘錄自：http://forge.mysql.com/wiki/ServerVariables 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

系統(tǒng)性能相關(guān)的MySQL變量

原文摘錄自：http://forge.mysql.com/wiki/ServerVariables

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
(會話變量) 控制在對沒有索引的表連接時分配的內(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Innodb) 控制分配給對Innodb內(nèi)部數(shù)據(jù)字典進行排序所需的緩沖。

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Innodb) 控制分配給對Innodb存儲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
(會話變量) 控制分配給讀取當前排序完的結(jié)果所需的緩沖總數(shù)。

sort_buffer_size
(PER SESSION) Controls the amount memory allocated to the buffer used to sort result sets before returning the set to the calling client
(會話變量) 控制在把結(jié)果返回給調(diào)用的客戶端之前需要對結(jié)果集進行排序所需的緩沖總數(shù)。

thread_stack
(PER SESSION) Controls the default stack memory allocated for each connecting thread
(會話變量) 控制分配給每個連接線程的默認堆棧內(nèi)存總數(shù)。

tmp_table_size
(GLOBAL) Controls the maximum memory to allocate to a temporary table before MySQL converts it into an on-disk MyISAM table
(全局變量) 控制MySQL在把一個臨時表轉(zhuǎn)換成磁盤存儲的MyISAM表時所需的最大內(nèi)存總數(shù)。

Thread-Related Variables
線程相關(guān)變量

thread_cache_size
(GLOBAL) Determines the number of thread connection objects that MySQL keeps in a cache to mitigate resource creation costs
(全局變量) 確定MySQL在緩存中保持的連接線程數(shù)量，這能減少創(chuàng)建連接時所需的系統(tǒng)資源。

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