这意味着DB2按顺序在表空间上提取每一个数据页面到缓冲池。
This means that DB2 fetches every data page in the table space sequentially into the buffer pool.
如果是使用大型数据集,可考虑用专用的缓冲池来代替表空间。
If you are working with large data sets, consider using a dedicated buffer pool for the table space.
然而,过多地分配空余空间可能会产生浪费的DASD 空间,导致每次I/O 只能传输更少的数据,缓冲池的利用效率更低,并且要扫描更多的页。
However, over-allocating free space may result in wasted DASD space, less data transferred per I/O, less efficient use of buffer pools and more pages to scan.
当从硬盘驱动器读写表和索引数据时,DB 2使用缓冲池来缓存它们。
DB2 USES buffer pools to cache the table and index data as they are being read or written to the hard disk drive.
通过将来自filemon、iostat和DB 2快照监视的数据与缓冲池监视开关相结合,可以得到以下信息。
By combining data from filemon, iostat, and DB2 snapshot monitoring with a buffer pool monitoring switch, you can develop the following information.
perl buffhitratio . pl dbrun. snap——该脚本提供了每个缓冲池的数据和索引页命中率。
Dbrun.snap - This script provides the hit ratio for the data and index pages of every buffer pool.
步骤 1:使用-l选项收集db2look,以收集表空间/缓冲池/数据库节点组信息。
Step1: Collect the db2look with the -l option to gather the tablespace/bufferpoo/database node group information.
缓冲池数据物理读数(以表空间页宽为单位定义)。
Buffer pool data physical reads (defined in units of tablespace page size).
每个数据库都至少需要一个缓冲池。
如果数据库没有启动,那么就不能连接到数据库,也就不能更改缓冲池的大小。
If the database is not started, you cannot connect to the database and change the buffer pool sizes.
当创建表空间时,可以将它与特定的缓冲区池(数据库缓存)关联起来,并关联到特定的容器。
When you create a table space, you can associate it with a specific buffer pool (database cache) as well as to specific containers.
当您设计缓冲池时,您应该考虑数据库的内存需求。
When you design buffer pools, you should consider the database memory requirements.
另一个极大影响性能的配置参数是数据库缓冲池大小。
Another configuration parameter that dramatically affects performance is the database buffer pool size.
这是用于数据库分区组、缓冲池和表空间的布局。
This is the layout for database partition groups, buffer pools and tablespaces.
数据库记录是在内存的缓冲池区域里被读取和更新的。
Database records are read and updated in the buffer pool area of memory.
与其他内存缓冲区相比,缓冲池对数据库性能的影响最为显著。
Compared to other memory buffers, buffer pools have the most significant impact on database performance.
除了缓冲池,排序是影响数据库性能的另一重要因素。
Besides the buffer pool, sort is another significant factor that impacts the database performance.
使用数据库系统监视器,利用有关从缓冲池进行写操作的快照数据(或事件监视器)信息来帮助您调优该配置参数。
Use the database system monitor to help you tune this configuration parameter using information from the snapshot data (or event monitor) about write activity from a buffer pool.
缓冲池竞争可以成为数据库性能中的重要因素。
Buffer pool contention can be a significant factor in database performance.
一个数据库必须至少有一个缓冲池,并且可以有多个缓冲池,这要视工作负载的特征、数据库中使用的数据库页面大小等因素而定。
A database must have at least one buffer pool, and can have a number of buffer pools depending on the workload characteristics, database page sizes used in the database, etc.
您将发现,与用于关系数据和索引的已有的计数器相对应,DB 29为XML数据提供了新的缓冲池快照监视器元素。
You will find that DB2 9 offers new buffer pool snapshot monitor elements for XML data that match the existing counters for relational data and indexes.
一个数据库必须至少有一个缓冲池,并且可以有多个缓冲池,具体要视工作负载的特征、数据库中使用的数据库页面大小等因素而定。
A database must have at least one buffer pool, and can have a number of buffer pools depending on such things as the workload characteristics and database page sizes used in the database.
有了从监控任务中收集的缓冲池运行时统计数据,您就可以知道是否任何性能获益都可以从缓冲池调优实现。
With the buffer pool runtime statistics gathered from the monitoring tasks, you can see whether any performance gain can be achieved from buffer pool tuning.
但是请记住,缓冲池是数据库共享内存集中的一部分。
However, keep in mind that buffer pools are part of the database Shared memory set.
数据库缓冲池通常是数据库共享内存中最大的一块内存。
The database buffer pool(s) area is normally the largest component of the database shared memory.
而所有的缓冲池是在数据库被激活时被分配的。
All buffer pools are allocated when the database is activated.
这样,一旦主缓冲池无法启动,DB 2还可以使用这些小型的缓冲池来启动数据库。
Should the main buffer pools fail to start, DB2 will start the database with the small buffer pools.
例如,缓冲池和数据库堆是数据库内存集内的两个不同的内存池。
For example, the buffer pools and the database heaps are two separate memory pools within the database memory set.
尽管在大型数据库测试中缓冲池从不超过1GB,但在并发性程度很高的小型数据库中,缓冲池的容量得到了充分的利用。
Although the buffer pool did not exceed 1 GB in the large-database tests, the smaller database and greater concurrency tests used every Megabyte possible.
预定义的ROT功能组织在缓冲池、数据库、表空间和SQL活动集群中。
The predefined ROT functions are organized in a buffer pool, database, table space and SQL activity cluster.
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