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缓冲池的疑问
看牛博士的关于调优db配置参数的内容，关于缓冲池有很多疑问，希望高人帮们解释一下
书上说默认情况下应用程序使用缓冲池IBMDEFAULTBP，当 syscat.bufferpools目录表中该
缓冲池的NPAGES为-1时，DB2数据库配置参数BUFFPAGE控制着缓冲池的大小，否则会
忽略BUFFPAGE参数，并且用NPAGES参数指定的页数创建缓冲池。
以下是我的环境中buffpools的参数：
db2 "select bpname,npages,pagesize from syscat.bufferpools"
BPNAME NPAGES PAGESIZE
----------------------------------------------------------------------------------
IBMDEFAULTBP -2 4096
DB_BP32K -2 32768
DB_LOG_BP32K -2 32768
书上说默认情况下应用程序使用缓冲池IBMDEFAULTBP，当 syscat.bufferpools目录表中该
缓冲池的NPAGES为-1时，DB2数据库配置参数BUFFPAGE控制着缓冲池的大小，否则会
忽略BUFFPAGE参数，并且用NPAGES参数指定的页数创建缓冲池。
以下是我的环境中buffpools的参数：
db2 "select bpname,npages,pagesize from syscat.bufferpools"
BPNAME NPAGES PAGESIZE
----------------------------------------------------------------------------------
IBMDEFAULTBP -2 4096
DB_BP32K -2 32768
DB_LOG_BP32K -2 32768
9同行回答
当self tuning被激活时，相应bufferpool的npages就是-2
牛博书上的这段话其实来自于SQL1482W的解释
dv01 {/home/dhost} > db2 ? sql1482
SQL1482W The BUFFPAGE parameter will only be used if one of the buffer
pools is defined with a size of -1.
Explanation:
This is a warning that the BUFFPAGE database configuration parameter
will be ignored if none of the database's buffer pools is defined with a
size of -1. -1 indicates that the buffer pool is to use the BUFFPAGE
parameter as the number of buffer pool pages.
User response:
You can select from the SYSCAT.BUFFERPOOLS to review the buffer pool
definitions. If none of the buffer pools are defined with size -1
(NPAGES), then setting the BUFFPAGE parameter will not change the size
of the buffer pools for the database.收起
牛博书上的这段话其实来自于SQL1482W的解释
dv01 {/home/dhost} > db2 ? sql1482
SQL1482W The BUFFPAGE parameter will only be used if one of the buffer
pools is defined with a size of -1.
Explanation:
This is a warning that the BUFFPAGE database configuration parameter
will be ignored if none of the database's buffer pools is defined with a
size of -1. -1 indicates that the buffer pool is to use the BUFFPAGE
parameter as the number of buffer pool pages.
User response:
You can select from the SYSCAT.BUFFERPOOLS to review the buffer pool
definitions. If none of the buffer pools are defined with size -1
(NPAGES), then setting the BUFFPAGE parameter will not change the size
of the buffer pools for the database.收起
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