The Java Virtual Machine's boot and extension class loaders have been enhanced to improve the cold-start time of Java applications. Prior to Java SE 6, opening the system jar file caused the Java Virtual Machine to read a one-megabyte ZIP index file that translated into a lot of disk seek...
1、使用磁盘Cache的时候非常占用磁盘空间:这是因为DiskCache的算法简单,该算法简单也导致Cache的效率非常高。它只是对元素直接追加存储。因此搜索元素的时候非常的快。如果使用DiskCache的,在很频繁的应用中,很快磁盘会满。 2、 不能保证数据的安全:当突然kill掉java的时候,可能会产生冲突,EhCache的解决方法是如果文件...
disk={true|false} Specifies whether to write temporary data to the disk repository. By default, this parameter is set to false. To enable it, set the parameter to true. dumponexit={true|false} Specifies whether a dump file of JFR data should be generated when the JVM terminates in a co...
There are several classes of applications where using 64-bit addressing can be useful. For example, those that store very large data sets in memory. Applications can now avoid the overhead of paging data from disk or extracting it from a RDBMS. This can lead to dramatic performance improvement...
Performance optimization 性能优化 Persistence 持久化 Resource pooling 资源池 Synchronization 同步 Transactions 事务 三、Mybatis MyBatis 是支持普通 SQL查询,存储过程和高级映射的优秀持久层框架。MyBatis 消除了几乎所有的JDBC代码和参数的手工设置以及结果集的检索。MyBatis 使用简单的 XML或注解用于配置和原始映射,...
Create a performance baseline. Make one change at a time. Be careful not to lose a winning tune because it's hidden by a bad tune made at the same time. Record all aspects of the system (app/component/version/version date/dependent software/CPU/Numbers of CPUs/RAM/Disk space/patches/OS...
the longer a GC cycle will take. The more classes that have to be loaded from disk into the JVM, the longer it will take for a program to start. The more code that is executed, the less likely that it will fit in the hardware caches on the machine. And the more code that has to...
disk with the Unix fsync() call (which InnoDB uses by default) and similar methods is surprisingly slow. If database write performance is an issue, conduct benchmarks with the innodb_flush_method parameter set to O_DSYNC. 其他刷出方式参考: optimization.html#optimizing-innodb-storage-layout ...
提供Hibernate的缓存实现缺点：1、使用磁盘Cache的时候非常占用磁盘空间：这是因为DiskCache的算法简单，...
计算机硬件经过25年的发展,内存与处理器虽然都在进步,但是内存延迟与处理器执行性能之间的冯诺依曼瓶颈(Von Neumann Bottleneck)不仅没有缩减,反而还在持续加大,“RAM Is the New Disk”已经从嘲讽梗逐渐成为了现实。 一次内存访问(将主内存数据调入处理器Cache)大约需要耗费数百个时钟周期,而大部分简单指令的执行只需...