java - commit-interval is not working as expected -

let say,we have 1000 items in db,and try fetch , delete 10 items,at time.for have implemented spring batch.

as per below configuration.

<batch:chunk reader="tokenreader" writer="tokenwriter" commit-interval="10"></batch:chunk> 

we have itemreader class,which fetch 10 item @ time db , passes list of 10 token itemwriter.

so after processing 10 items,it should commit ideally.

but facing below issue.

with commit-interval = 10,joblauncher launching 10 threads,and each thread fetching same 10 tokens database,and once itemreader passes list of 10 token itemwriter,we receive exception("the token marked deleted" jpa exception).

however if set commit-interval = 1,it starts 1 thread , execute fetch , delete 10 items @ time.