Database corrupted?

We have a ORACLE 8.0.5 database on NT4 served as data source for an Intergraph GIS system. The size of database is ~2gb, the drive the database residing is 4 gb. In past three days, I have had the following problems

-some times when I try to connect database I got messages "ORA-03113:
end-of-file on communication channel" and " DBW0:terminating instance due to error 1092". Then after a while I can connect with either sqlplus or svrmgr30. However, connection is much slower, taking 20-30 seconds.

-queries generally runs slower than before, especially count(*) query, maybe
10 times slower.

-When I run snap8.sql usually take less than 2 minutes. It hangs when I run
it at retrieving datafile information. I checked the query, seems like dba_extents was the key of slowdown. I queried dba_extents alone and noticed that it stopped at four or five segments for a long time before moving forward again (total rows retrieved by the query is 2987). Query of user_extents with a login of a user also run very slow.

-The GIS system has real performance problem, some task used to take less
than a minute may take more than a hour now.

I checked V$datafile looks like all datafiles are online. I'm not sure all above symptoms were related to the same problem. Please help me to diagnose.

Thanks.

Al Received on Wed Jan 09 2002 - 16:02:38 CST