> Rather than replacing just the storage manager, you'd be replacing
> the access methods, buffer manager, transaction manager, and some
> of the shared memory plumbing with our stuff.  I wasn't sufficiently
> clear in my earlier message, and talked about "no-overwrite" as if
> it were the only component.
> 
> Clearly, that's a lot of work.  On the other hand, you'd have the
> benefit of an extremely well-tested and widely deployed library to
> provide those services.  Lots of different groups have used the
> software, so the abstractions that the API presents are well-thought
> out and work well in most cases.

True. But after replacement the system as whole would not be well-tested.
"A lot of work" means "a lot of bugs, errors etc".

> The group is interested in multi-version concurrency control, so that
> readers never block on writers.  If that's genuinely critical, we'd
> be willing to see some work done to add it to Berkeley DB, so that it
> can do either conventional 2PL without versioning, or MV.  Naturally,

This would be the first system with both types of CC -:)

Well, so, before replacing anything we would have to add MVCC to BDB.
I still didn't look at your sources, 'll do in a few days...

Vadim

Tue, 16 May 2000 09:26:28 -0700
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM>
RE: Berkeley DB license
> > The group is interested in multi-version concurrency control, so that
> > readers never block on writers.  If that's genuinely critical, we'd
> > be willing to see some work done to add it to Berkeley DB, so that it
> > can do either conventional 2PL without versioning, or MV.  Naturally,
> 
> This would be the first system with both types of CC -:)
> 
> Well, so, before replacing anything we would have to add MVCC to BDB.
> I still didn't look at your sources, 'll do in a few days...

Vadim, I thought you said you were going to be doing a new storage
manager for 7.2, including an over-write storage manager that keeps MVCC
tuples in a separate location.  Could SDB work in that environment
easier, without having MVCC integrated into SDB?

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Tue, 16 May 2000 13:54:21 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: Berkeley DB license