Re: 2-phase commit

The world rejoiced as t-ishii(at)sra(dot)co(dot)jp (Tatsuo Ishii) wrote:
> I'm tired of this kind of "2PC is too slow" arguments. I think
> Satoshi, the only guy who made a trial implementation of 2PC for
> PostgreSQL, has already showed that 2PC is not that slow.

I'm tired of it for a different reason, namely that there are "use
cases" where speed is not _relevant_. The REAL problem that is taking
place is that people are talking past each other.

- Some say, "It's too slow; no point in doing it."

The fact that it may be too slow _for them_ means they probably
shouldn't use it. I somehow doubt that there are Vastly Faster
alternatives waiting in the wings.

- The other problem that gets pointed out: "2PC is inherently
fragile, and prone to deadlock."

Again, those that _need_ to use 2PC will forcibly need to address
those concerns in the way they manage their systems.

Those that can't afford the fragility are not 'customers' for use of
2PC. And, pointing back to the speed controversy, it is not at all
obvious that there is any other alternative for handling distributed
processing that _totally addresses_ the concerns about fragility.

Those that can't afford these costs associated with 2PC will simply
Not Use It.

Probably in much the same way that most people _aren't_ using
replication. And most people _aren't_ using PL/R. And most people
_aren't_ using any number of the contributed things.

If 2PC gets implemented, that simply means that there will be another
module that some will be interested in, and which many people won't
bother using. Which shouldn't seem to be a particularly big deal.
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