免费下载资源
今天在一台配置很低的机器上运行批量更新的程序~~~
大概跑了三十分钟~~~这配置~~~这程序~~~
然后华丽丽的报异常了~~~
具体异常是这样的,
|
1
2
3
4
5
6
7
8
9
10
11
12
13
|
DEBUG: (BaseJdbcLogger.java:
132
) ooo Using Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl
@4d4e22e1
]
[
2014
-
07
-
17
15
:
19
:
35
]
5363945354
[Druid-ConnectionPool-Destory-
1422598563
] com.alibaba.druid.pool.DruidDataSource:
1132
WARN : (DruidDataSource.java:
1132
) get/close not same thread
ERROR: (DruidDataSource.java:
1815
) abandon connection, open stackTrace
at java.lang.Thread.getStackTrace(Thread.java:
1588
)
at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:
942
)
at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:
4534
)
at com.alibaba.druid.filter.stat.StatFilter.dataSource_getConnection(StatFilter.java:
661
)
at com.alibaba.druid.filter.FilterChainImpl.dataSource_connect(FilterChainImpl.java:
4530
)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:
880
)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:
872
)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:
97
)
|
这个是最初的异常, 后面还有一大批异常,
|
1
2
3
4
5
|
Caused by: java.sql.SQLException: connection holder is
null
at com.alibaba.druid.pool.DruidPooledConnection.checkState(DruidPooledConnection.java:
1085
)
at com.alibaba.druid.pool.DruidPooledConnection.getMetaData(DruidPooledConnection.java:
825
)
at org.springframework.jdbc.support.JdbcUtils.extractDatabaseMetaData(JdbcUtils.java:
285
)
...
70
more
|
说什么holder为空
第一眼看到holder就像到Spring的源码, 里面到处是holder(笑)
但是这里的holder不是Spirng里面的,是Druid的
这个holder大概是用来hou住连接池里面的连接的.
然后为什么为空了呢? 目测是哪个链接坏了, 或者被意外的关闭了...
根据异常调源码 at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:942)
|
1
2
3
4
5
6
7
8
9
10
|
941
if
(isRemoveAbandoned()) {
942
StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
943
poolalbeConnection.setConnectStackTrace(stackTrace);
poolalbeConnection.setConnectedTimeNano();
poolalbeConnection.setTraceEnable(
true
);
synchronized
(activeConnections) {
activeConnections.put(poolalbeConnection, PRESENT);
}
}
|
看不出啥来. 只能将日志继续看看, 还是看不出啥来
然后看了上面代码几遍后, 老觉得 isRemoveAbandoned() 这个方法有鬼.
查看调用处,:
恩, 这个DestroyConnectionThread非常可疑, 跳
|
1
2
3
|
if
(isRemoveAbandoned()) {
removeAbandoned();
}
|
继续
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
|
public
int
removeAbandoned() {
int
removeCount =
0
;
long
currrentNanos = System.nanoTime();
List<DruidPooledConnection> abandonedList =
new
ArrayList<DruidPooledConnection>();
synchronized
(activeConnections) {
Iterator<DruidPooledConnection> iter = activeConnections.keySet().iterator();
for
(; iter.hasNext();) {
DruidPooledConnection pooledConnection = iter.next();
if
(pooledConnection.isRunning()) {
continue
;
}
long
timeMillis = (currrentNanos - pooledConnection.getConnectedTimeNano()) / (
1000
*
1000
);
if
(timeMillis >= removeAbandonedTimeoutMillis) {
iter.remove();
pooledConnection.setTraceEnable(
false
);
abandonedList.add(pooledConnection);
}
}
} ....略
}
|
擦, 这里不对头, timeMillis >= removeAbandonedTimeoutMillis timeMillis 这个是getConnection()被调用时的时间
意思就是一个连接被get后, 超过了 removeAbandonedTimeoutMillis这么久我就弄死你.
然后继续找removeAbandonedTimeoutMillis 这玩意在哪里设置的 ,最后发现是在
<property name="removeAbandoned" value="true" />
<property name="removeAbandonedTimeout" value="1800" />
初始化配置的这里设置的, 这两个参数的大概意思就是,
通过datasource.getConnontion() 取得的连接必须在removeAbandonedTimeout这么多秒内调用close(),要不我就弄死你.(就是conn不能超过指定的租期)
然后调成2个小时~~~
然后程序成功跑完~~~华丽丽的等了50分钟
总结:
连接池为了防止程序从池里取得连接后忘记归还的情况, 而提供了一些参数来设置一个租期, 使用这个可以在一定程度上防止连接泄漏
但是如果你的业务真要跑这么久~~~~那还是注意下这个设置.
http://my.oschina.net/haogrgr/blog/224010
27.83 K
8.56 K
已为社区贡献8条内容
所有评论(0)