重复 1.repeat; duplicate; reduplicate; iterate 他把那个词重复了几遍。 he repeated the word several times.2.repetition; reiteration; gemination; rerun; duplication; replication; palin-; pali- 避免不必要的重复 avoid needless duplication; 经过无数次的重复 after numerous repetitions; 任何历史现象都不会是简单的重复。 no historical phenomenon is a mere repetition of the past
Second lost updates problem ? a special case of an unrepeatable read 两次更新问题无法重复读取的特例。
If you need a moment to think , repeat the question 如果你需要时间思考如何用口语表达出来,重复读这个问题。
This leaves you a choice between read committed and repeatable read 剩下的也就是在“授权读取”和“可重复读取”之间选择了。
Repeatable read - rr 可重复读rr
Non repeatable read 不可重复读
Incorrect concurrency can lead to problems such as dirty reads , phantom reads , and non - repeatable reads 不正确的并发可能导致脏读、幻读和不可重复读等问题。
This is an important issue , but using repeatable read isn ' t the only way to resolve it 这是一个非常重要的问题,但是使用可重复读取并不是解决问题的唯一途径。
For example , reading from a read - only look up table doesn t require repeatable read , and uncommitted read is sufficient 比如,读取只读的查找表不需要可重复读级别,未提交读级别就足够了。
If the transaction isolation mode is repeatable read , then the optimizer would base its choice purely on the estimated costs 如果事务隔离模式是可重复读( repeatable read ) ,那么优化器会将其选择完全基于估算成本。
For the four levels of isolation supported , table 6 shows whether phantom , dirty , or non - repeatable read is possible from strongest to weakest 针对受支持的四种隔离级别,表6列出了出现幻像读、脏读或不可重复读的可能性(从高到低) 。