Re: Tuple concurrency issue in large objects

Justin  writes:
> I have a question reading through this email chain.   Does Large Objects
> table using these functions work like normal MVCC where there can be two
> versions of a large object in pg_largeobject .

Yes, otherwise you could never roll back a transaction that'd modified
a large object.

> My gut says no as
> moving/copying potentially 4 TB of data would kill any IO.

Well, it's done on a per-chunk basis (normally about 2K per chunk),
so you won't do that much I/O unless you're changing all of a 4TB
object.

			regards, tom lane