Our first major problem is that we are scanning the full bills table every time we want a row out of it and locking every row we read.
我们的第一个主要问题是,当我们想要一行的内容时,我们会扫描整个账单表,并锁定我们读取的每一行。
This reduces the amount of locking within the database manager and reduces the processing cost of the read.
这样可减少数据库管理器中的锁定量,从而减少线程的处理成本。
This will reduce the amount of locking that the database manager has to perform and result in better read performance.
这将减少数据库管理器必须执行的锁定量从而提高读的性能。
Locking occurs on two levels (see Listing 7) : The list has a read-write lock, while individual nodes contain a mutex.
在两个级别上执行锁定(见清单7):链表有一个读写锁,各个节点包含一个互斥锁。
However, for entity beans this rule has to be relaxed; due to the nature of the model, most pessimistic locking access intents require at least Repeatable Read.
但是,对于实体Bean则可不遵循此规则,由于该模型本身的特性,多数悲观锁定访问都需要至少RepeatableRead。
Read-Committed is the minimum level required for optimistic locking to work.
Read-Committed是乐观锁工作所需的最低级别。
A newly added "currently committed" locking syntax eliminates the conflict between read and write workloads so the database can deliver a true point-in-time response.
新增的“currentlycommitted”锁语法可以消除读和写工作负载之间的冲突,让数据库实现真正的时间点响应。
Supports table and row level locking and 4 isolation levels, RR (repeatable read), rs (read stability), CS (default - cursor stability) and ur (uncommitted read).
支持表级和行级锁以及4个隔离级别:RR(可重复读)、RS(读可靠)、CS(默认——游标可靠)和UR(未提交读)。
This script will read the Informix system tables, find out which tables have page-level locking, and then generate another SQL script to change those tables to row-level locking.
此脚本将读取Informix系统表,找出哪些表具有页面级锁定,然后生成另一段sql脚本来将这些表更改为行级别锁定。
In fact, the only row-level locking that remains during INSERT is the next-key locks that are required to protect an INSERT from adding keys to repeatable read scanners.
实际上,在INSERT期间惟一保持的行级锁是next - key锁,这个锁用于使INSERT不会添加键到可重复的读扫描器。
If the workload is a read mostly workload, then solutions like caching with optimistic locking work well.
如果工作负荷主要是读取,那么诸如使用最优锁定进行缓存的解决方案可以很有效。
However, you can use volatile to ensure the visibility of the current value when reading, so you use locking for all mutative operations and volatile for read-only operations.
然而,您可以在读操作中使用volatile确保当前值的可见性,因此可以使用锁进行所有变化的操作,使用volatile进行只读操作。
Optimistic Locking is a strategy where you read a record, take note of a version number and check that the version hasn't changed before you write the record back.
乐观锁是这样一种策略,你可以读取记录,记录版本号并检查,在你写回之前该版本没有改变。
Optimistic Locking is a strategy where you read a record, take note of a version number and check that the version hasn't changed before you write the record back.
乐观锁是这样一种策略,你可以读取记录,记录版本号并检查,在你写回之前该版本没有改变。
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