The minimum number of buffer pages is 18 and the maximum is 4096.
缓冲区页面最少为18,最大为 4097。
You would want to do this on situations where frequent backups are not possible, or to force changed pages off buffer pools before performing copy activities outside DB2.
在不需要进行频繁备份的情况下可以这么做,或者在DB2之外执行复制活动之前强制发生变更的页面离开缓冲池。
Thus, the read operations compete with log writing and the write operation for data pages from the buffer pool.
因而,读操作与日志写和缓冲池中的数据页的写操作之间存在竞争。
This requires the appropriate index pages to be in the buffer pool.
这要求在缓冲池中存在适当的索引页。
Increase the log buffer size to 256 pages or larger.
将日志缓冲区大小增加到256个页面或更大。
This recovery process instantly begins to prefetch dirty pages from the centralized buffer pool into its own local buffer pool.
这个恢复进程立即开始将脏页从集中式缓冲池预取到它自己的本地缓冲池。
If rows are accessed randomly, then the smaller page size enables DB2 to make better use of the buffer, because more pages fit into the same storage area.
如果随机访问行,那么较小的页大小让db2可以更好地利用缓冲区,因为同样的存储区域可以容纳更多页。
This parameter determines the threshold percentage of dirty pages in the buffer pool at which page cleaning will be initiated.
这个参数决定缓冲池中脏页的阈值百分比,当脏页达到这个百分比时,就会启动页清除。
Virtual segment also contains dictionary cache, stored procedures cache, and big buffer pools used for writing large block of pages to disk at once.
虚拟内存段还包含字典缓存器,存储过程缓存器,以及在向磁盘一次性写入大块页面时使用到的较大的缓冲池。
If this is the case, a larger buffer pool is the best solution, but adding more free space to index pages may also help.
如果的确是上述情况,那么使用更大的缓冲池是最好的解决办法,但是为索引页增加更多的自由空间也有所帮助。
This calculation takes into account all of the pages (index and data) that are cached by the buffer pool.
这个计算考虑了缓冲池高速缓存的所有页(索引和数据)。
You might also have a query that runs against a very large table that USES the same buffer pool and involves reading more pages than the total buffer size.
假设有一个针对非常大的表运行的查询,它使用同一个缓冲池并且需要读取比总的缓存区大小还多的页。
The hit ratios for data and index pages reflect the number of times a page request was handled by the buffer pool directly without requiring disk I/O.
数据和索引页面的击中率反映了缓冲池在不需要磁盘I/O的情况下直接处理一个页面请求的时间量。
Transactions requiring disk I/O, such as flushing dirty pages from the buffer pool or flushing logs from the log buffer, may wait.
要求磁盘I/O 的事务,例如刷新缓冲池中的脏页或者刷新日志缓冲区中的日志,可能需要等待。
Pagination is the process of breaking a single page into multiple pages in order to fit the page size within acceptable limits of the device buffer.
分页是为了使页面大小适合设备缓冲可接受的限制而将单个页面分解成多个页面的过程。
With the bigger buffer pool of 12000 4k pages, the performance result improves from 43 completed transactions per 10 seconds to 66 completed transactions, as shown in Figure 4.
通过12000个4K页面的更大缓冲池,性能结果从每10秒完成43个事务增加到完成66个事务,如图4中所示。
These page cleaners write changed pages from the buffer pool to disk before the space in the buffer pool is required by a database agent.
在数据库代理程序需要缓冲池中的空间之前,这些页清除程序将缓冲池中已更改的页写到磁盘。
Once fetched into DB2 buffer pools, records in these pages are scanned and the stage-1 predicate is applied.
一旦提取到DB2 的缓冲池,将扫描在这些页面上的记录并应用阶段 1 谓词。
For other platforms, the buffer pool size is 250 pages with a 4k pagesize.
而在其他平台上,缓冲池大小为250个页大小为4k的页。
If the small tables have their own buffer pool, thereby making it necessary for them to have their own table space, their pages cannot be overwritten by the large query.
如果小型表拥有自己的缓冲池,那么它们就必须拥有自己的表空间,因此大型查询就不能覆盖它们的页。
Whenever an application posts a send or receive, and AFD.SYS's buffering is disabled, all pages in the buffer are locked into physical memory.
如果你把AFD . SYS的缓冲关闭,当应用程序收发数据时,应用程序缓冲区的所有页面将被锁定到物理内存中。
Page cleaners, on the other hand, write changed pages from the buffer pool to disk before the space in the buffer pool is required by a database agent.
另一方面,数据库代理需要缓冲池中的空间之前,页面清洗器将已修改的页面从缓冲池写入磁盘。
If the hit ratio is low, increasing the number of buffer pool pages may improve performance.
如果命中率较低,则可以增加缓冲池页数来提高性能。
With the buffer pool size of 250 pages, the application test run experienced very poor buffer pool hit ratio of 48.69%.
通过250个页面的缓冲池大小,应用程序测试运行呈现了48.69%的糟糕的缓冲池命中率。
What happens if you increase the buffer pool size to 20,000 4K pages and run PERFORMER again?
如果将缓冲池大小增加到 20,000 个4K页面并重新运行 PERFORMER,那将会发生什么情况呢?
The qualifying RIDs are then taken by the fetch node to fetch the corresponding records and data pages from the table space into the DB2 buffer pool.
然后通过FETCH节点获取合格的RID以提取来自表格空间的相应记录和数据页面到db2缓冲池。
Furthermore, compressed pages of a DB2 table space remain compressed in the DB2 buffer pool in main memory.
而且DB 2表空间的压缩页在主内存的db2缓冲池中仍保持压缩。
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.
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。
For example, if you had a 2 GB buffer pool, when 60% of changed pages is reached, 1.2 GB (60% of 2 GB) would be written to disk as page cleaners are triggered.
例如,如果您具有一个2GB的缓冲池,当达到60%的修改页面时,在触发页面清洗器时就有1.2 GB (2 GB的60%)将写入磁盘。
By default, JSP pages have an 8kb buffer, which is flushed automatically when it's full of the dynamically generated HTML.
默认状态下,jsp页面具有一个8kb的缓冲区,满载动态生成的HTML后,它会自动刷新。
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