Elapsed Time in Statspack report

Question

There is a java process that made updates to 1 millon rows in the oracle database table. A commit was issued after each update statement in the code. There were 10 java threads(processes) involved in updating the 1 million rows and the total time took 3 hours and 40 minutes. However, in the statspack report pulled for that time period, it indicates that the total elapsed time was 4 hours and 3 minutes. What may be the cause for this difference ?

Answer 1

Thanks to all. I was also reading the same site. ALso what does these mean in case of session details.
memory sorts, table scans, physical reads, logical reads, cursors.
In some of the sessions I have these figures. What can I figure out from this.
(giving the output in vertical way)
ID 105
Status - INACTIVE
Machine- ebank_prd
User Name - EVENT
Elapsed Time- 16,237
CPU Used     -645
Memory Sorts-25
Table Scans - 7866
Physical Reads -134
Logical Reads- 115249
Commits     7981
Cursor 104     
Buffer Cache Hit Ratio 100
Another one :
26,INACTIVE,ebank_prd,CAIORA, 239,105, 31,093, 9,636, 67,032, 56,334 45,543, 860     0     8     100
Here the epalsed time is 239,105,
cpu used is 31,093
memory sorts is 9,636
table scans is 67,032
physical read 56,334
logical reads 45,543,860
The figures are so high
I performance is slow and what shall I do next to find out whats wrong by looking at the values.
Waiting for your answer.
Thanks again
SL