Subject Re: Questions on concurrent updates
Author Sean
--- In, "Ann W. Harrison"
<aharrison@...> wrote:
> Sean wrote:
> >
> > 1. I have a table with 3 columns, {ID, A, B}.
> >
> > There are two transactions, TransA and TransB. TransA updates column A
> > of a row, and TransB updates column B of the *same* row. Both
> > transactions use READ COMMITTED isolation with RECORD_VERSION.
> >
> > Say, TransA comes in first and then TransB. TransA modifies the column
> > A and commits. TransB updates column B. Since TransB's TID is newer
> > than TransA's, TransB can commit the modification successfully, I
> TransB updates the version of the record that A committed, as long as
> it doesn't have to wait for A. If it waits, it will get an error when
> A commits.

Since both transactions use READ COMMITTED isolation with
RECORD_VERSION, even B waits for A to commit, B can still post and
commit over the newer version from A, right?