"Joshua D. Drake" <jd@commandprompt.com> writes:
> I just read a rather disturbing post....
> PostgreSQL does not support read uncommited and repeatable read
> isolation levels? If that is so... then PostgreSQL is NOT ACID compliant?
Why do you find that disturbing? Read uncommitted is the very
definition of "not ACID".
> What is the real deal on this?
We don't support read uncommitted because it's not ACID, and we don't
support repeatable read because it doesn't map to any useful behavior in
an MVCC model. It is legal to omit support for these isolation levels
per spec. (I think the spec actually wants implementations to silently
treat them as the next higher isolation level rather than complaining,
but that seems to me like it'd just add confusion.)
Anyone who tries to paint this as a big deal is just trolling.
regards, tom lane