David Fetter wrote:
> Kevin Grittner sent in four revisions of a patch to add a optimize
> and correct SERIALIZABLE so that it doesn't switch from READ ONLY
> DEFERRABLE mode to READ WRITE.
Correction: this is a patch to prevent the READ ONLY property of any
transaction from being changed after a transaction (of any isolation
level) acquires its first snapshot, except that a subtransaction can
set its level to READ ONLY when the parent transaction level is READ
WRITE. I was motivated to do so largely because it allows certain
optimizations in the Serializable Snapshot Isolation patch, but also
because of standards compliance issues.
-Kevin