Understanding Innodb History Length – Part 2
NOTE : Please read Part 1 before proceeding further . Part 1 discusses isolation levels , roll ptr and other basic concepts . This article has advanced content and is hard to understand unless you grasp the concepts from Part 1 Read-view computation CREATE TABLE `t` ( `id` int(11) DEFAULT NULL, `c` char(30) DEFAULT […]
Understanding Innodb History Length – Part 1
Introduction: InnoDB has concept of history length that represents number of undo logs (or rollback segments) that has pending purge. It is necessary to understand why this variable should be tracked and what effect it has on overall transaction processing. But just tracking history length is not enough. Once user discovers that is is higher […]