Enqueue and DB File Sequential Read Waits Problem

We have a batch job taking a long time to process. Querying the v$session_wait view, I discovered there have been over 1200 enqueue waits, with an average wait of just over 307 and a max wait of 308. The total time waited is 370081 (just over one hour if these figures are in centiseconds). The batch job has been running about 6 hours.

I also see that db file sequential read has waited almost 4 hours. This sounds like 4 hours waiting on index access requests. What could cause these long waits?

I am not sure how to troubleshoot this problem further (Reading the Performance 101 Book is on My To Do List). This is Oracle 81630 on Windows NT server.

Any suggestions or advice on how to troubleshoot this further is much appreciated. Here is my query and the output:

SQL> l
  1 select substr(event, 1,30), total_waits, time_waited, average_wait, max_wait
  2 from v$session_event
  3* where sid=18
SQL> / SUBSTR(EVENT,1,30) TOTAL_WAITS TIME_WAITED AVERAGE_WAIT MAX_WAIT

------------------------------ 		----------------------
-------------------- 	-----------------------
---------------------
latch free                              	 5           	0
0         		 	0
enqueue                               	1204      	370081
307.376246      		308
buffer busy waits                       	45           	0
0          			0
log file switch completion            2          	27         	13.5
17
log file sync                            	4           	0
0          			0
db file sequential read            	7269278     	1375000


.18915221       		29

direct path read                         	4          		10
2.5         		10
direct path write                     	1098         	112


.102003643        	2

file open                                	4           	0
0          			0
SQL*Net message to client        555           	0            	0
0
SQL*Net more data to client       11           	1   		.090909091
1
SQL*Net message from client     555		3256   		5.86666667

Thanks again for any pointers and suggestions.

Sam Bootsma, OCP
Technical Support Analyst

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