Questions about sender JDBC adapter

Question

Normally we use sender jdbc adapter in this way:
query statement:
SELECT * FROM table WHERE processed = 0
update statement:
UPDATE table SET processed = 1 WHERE processed = 0;
The update statement will be executed after the message has been successfully sent to XI.
My questions is that what will happen in this scenario:
A new record (processed=0) is added to the database table when a message is sent to XI with query statement but not finished?
After the message is sent to XI successfully, XI will execute the update statement. Then  the new added reocrd will also be updated to 1 although it hasn't been sent to XI.
Does XI have some control or special check for this issue?
Regards
Hui

Answer 1

Hi,
this can be handled by the ISOLATION LEVEL FOR TRANSACTION  setting of the sender Jdbc adapter.
make the transaction handling to SERIALIZABLE  or REPEATABLE READ and then until the data is not read from the JDBC adapter and it is not updated by the UPDATE statement , no new rows will be allowed to be inserted into the database. The database will be write locked.
http://help.sap.com/saphelp_nw04/helpdata/en/7e/5df96381ec72468a00815dd80f8b63/content.htm
<i>Isolation Level for Transaction
There are different levels of database transactions known as isolation levels. The isolation level determines how transactions running in parallel influence each other. The options correspond to the JDBC constants:
   Default (default setting of the respective database)
     None
    read_uncommitted (weakest setting)
    read_committed
     repeatable_read
     serializable (strongest setting)</i>
Regards,
Bhavesh