mysql5.6和mysql5.7分配undo復原段的區別，mysql5.6mysql5.7

mysql5.6和mysql5.7分配undo復原段的區別，mysql5.6mysql5.7

1、mysql5.7中分為2類：暫存資料表空間復原段和普通復原段。

2、mysql5.6中沒有區分。

As ofMySQL 5.7.2, 32 undo logs are reserved for use by temporary tables and are hosted in the temporary table tablespace (ibtmp1). To allocate additional undo logs for data-modifying transactions that generate undo records,innodb_undo_logs must be set to a value greater than 32 if undo logs are stored in the system tablespace only. If you have configured separate undo tablespaces, innodb_undo_logs must be set to a value greater than 33 to allocate additional undo logs for data-modifying transactions. Each undo log can host up to a maximum of 1024 transactions.

如果undo log儲存在系統資料表空間，innodb_undo_logs值必須大於32

否則隔離儲存區 (Isolated Storage)的話必須大於3。

參考：

http://www.tuicool.com/articles/IzQNRrz

http://dev.mysql.com/doc/refman/5.7/en/innodb-parameters.html#sysvar_innodb_undo_logs

http://dev.mysql.com/doc/refman/5.6/en/innodb-parameters.html#sysvar_innodb_undo_logs

http://bbs.aliyun.com/read/244045.html?spm=5176.7189909.0.0.AB00as

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