【IT168技术文档】项目组反应数据库有问题，
检查发现sga还用的默认参数，缓冲区命中率很低。根据系统内存调整后，好像系统正常了。数据库调整就算是结束了
一天后，我再登这个数据库的时候，发现一个提示说线程已经超过限制，不允许再登录。然后我去修改了process到250，增加并发连接数。然后重启了数据库。当天没发生什么事情，第二天，发现250又被撑满了，这个时候，我就开始换衣中间件有问题，登入中间件那边看了下日志，一直报错，提示无法打开新的连接。一般来说，中间件连接数据库能开10个都算可以了。至少websphere是这样，weblogic应该差不多。然后修改了一下，调整了weblogic的连接池，修改最大连接到100.
1、 报错信息
<2008-4-22 上午04时33分18秒 CST>
hread: '1' for queue: 'weblogic.kernel.Default' has been busy for "102" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时33分18秒 CST>
hread: '7' for queue: 'weblogic.kernel.Default' has been busy for "178" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时34分18秒 CST>
hread: '0' for queue: 'weblogic.kernel.Default' has been busy for "111" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时34分18秒 CST>
hread: '1' for queue: 'weblogic.kernel.Default' has been busy for "162" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时35分18秒 CST>
hread: '0' for queue: 'weblogic.kernel.Default' has been busy for "171" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时35分18秒 CST>
hread: '12' for queue: 'weblogic.kernel.Default' has been busy for "111" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
<2008-4-22 上午04时36分18秒 CST>
hread: '12' for queue: 'weblogic.kernel.Default' has been busy for "171" seconds
working on the request "Http Request: /guestAction.jsp", which is more than the
configured time (StuckThreadMaxTime) of "60" seconds.>
2、判断 可能存在部分sql语句未优化，造成执行时间过长(request超时)造成挂死
3、解决
开发模式和产品模式的一些参数的默认值不同，可能会对性能造成影响，下面是对性能有影响的参数列表：
参数 开发模式默认值 产品模式默认值
Execute Queue: Thread Count 15 threads 25 threads
JDBC Connection Pool: MaxCapacity 15 connnections 25 connections
通过启动管理控制台，在域(如：mydomain)> 配置 > 常规选择产品模式。
修改了server-myserver参数中的threadcount参数，按照cpu数量，修改为100
修改jdbc数据库连接池，修改为初始15，最大100。
晚间进行跟踪，系统运行正常，高峰时段，尤其是早晨的高峰时段，系统没有再出现挂死的问题。
早晨点击页面查询发现有时会出现页面无法访问的情况。
跟踪发现weblogic最高时有100多并发，同时注意到内存占用比较高，检查发现，原来内存配置较低。
检查原配置文件：
:bea
if "%PRODUCTION_MODE%" == "true" goto
bea_prod_mode
set JAVA_VM=-jrockit
set MEM_ARGS=-Xms96m -Xmx256m
set
JAVA_OPTIONS=%JAVA_OPTIONS% -Xverify:none
goto
continue
:bea_prod_mode
set JAVA_VM=-jrockit
set MEM_ARGS=-Xms128m
-Xmx256m
goto continue
:sun
if "%PRODUCTION_MODE%" == "true" goto sun_prod_mode
set
JAVA_VM=-client
set MEM_ARGS=-Xms32m -Xmx200m -XX:MaxPermSize=128m
set
JAVA_OPTIONS=%JAVA_OPTIONS% -Xverify:none
goto
continue
:sun_prod_mode
set JAVA_VM=-server
set MEM_ARGS=-Xms32m
-Xmx200m -XX:MaxPermSize=128m
goto continue
很明显配置为96m，最高256m。修改后的参数：
修改后结果为
:bea
if "%PRODUCTION_MODE%" == "true" goto
bea_prod_mode
set JAVA_VM=-jrockit
set MEM_ARGS=-Xms256m -Xmx768m
set
JAVA_OPTIONS=%JAVA_OPTIONS% -Xverify:none
goto
continue
:bea_prod_mode
set JAVA_VM=-jrockit
set MEM_ARGS=-Xms256m
-Xmx768m
goto continue
:sun
if "%PRODUCTION_MODE%" == "true" goto sun_prod_mode
set
JAVA_VM=-client
set MEM_ARGS=-Xms256m -Xmx768m -XX:MaxPermSize=128m
set
JAVA_OPTIONS=%JAVA_OPTIONS% -Xverify:none
goto
continue
:sun_prod_mode
set JAVA_VM=-server
set MEM_ARGS=-Xms256m
-Xmx768m -XX:MaxPermSize=128m
goto continue
:continue
最低256，最高768.查看跟踪信息比较调整前后性能：
调整前内存
调整后情况：
现在垃圾回收不那么频繁了，整体稳定性应该有好处。再频繁打开一个页面的情况下，页面仍然能正常显示。
