select of partial inserted rows possible?

[ovms]

Hi,
We are using IBM DB2 in linux platform version 9.7.
We use default CS isolation level and have two programs running
concurrently, one insert records and commit every 200 rows while
another select those inserted records based on a unique sequence
number, from the last obtained sequence number. (select from T1 where
sequence number = last sequence number, fetch 50 rows each time. )

We found that some of the rows inserted was missed by the select
program.

Any idea why this happen and how to prevent it , if RR isolation level
is not prefered.

PC

[ovms]

Further clarify, the reason we found some of the rows inserted was
missed was because the select start from the last sequence number for
50 rows, we suspect that some row of higher sequence number was seen
by the select statement before some with lower sequence number when
they are both committed within same unit of work by the inserting
program.
The question is: is it normal to have inserted rows partially revealed
to another selected program running currently and anyway to avoid
this?