数据库问题

不太懂数据库，求解。。。


前置机，C的，还有个有个数据库，oracle 9.2.0的，一两个月数据库死一次，
不交易时，刷的listener.log如下：
28-JUL-2011 00:42:04 * service_update * pos * 0
28-JUL-2011 00:46:25 * service_update * pos * 0
28-JUL-2011 00:47:28 * service_update * pos * 0

交易时，刷的listener.log如下：
28-JUL-2011 10:49:26 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=pos)(CID=(PROGRAM=PToCtl)(HOST=localhost.localdomain)(USER=posp))) * (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=55039)) * establish * pos * 0
28-JUL-2011 10:49:26 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=pos)(CID=(PROGRAM=MPosSvr)(HOST=localhost.localdomain)(USER=posp))) * (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=55040)) * establish * pos * 0
28-JUL-2011 10:49:26 * (CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=pos)(CID=(PROGRAM=MPosBdg)(HOST=localhost.localdomain)(USER=posp))) * (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=55041)) * establish * pos * 0



现在就是数据库有可能死掉，就是数据库没反应，命令没用，C程序连不上去，DBSconnect等死那了，然后整个程序就不动了（没超时控制），每次要重启机器才行，看了一下listener.log，发现在凌晨3点多的时候（没交易的），
28-JUL-2011 03:42:04 * service_update * pos * 0
28-JUL-2011 03:46:25 * service_update * pos * 0
这种日志不刷了，正常应该一直刷，重启后就正常了，求可能的原因。。


另外，listener.log 里还有这个。。
Started with pid=3289

Started with pid=3287
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1)))
Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost.localdomain)(PORT=1521)))
Error listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-12542: TNS:address already in use
TNS-12560: TNS:protocol adapter error
TNS-00512: Address already in use
Linux Error: 98: Address already in use
Listener completed notification to CRS on start

TIMESTAMP * CONNECT DATA [* PROTOCOL INFO] * EVENT [* SID] * RETURN CODE