Re: Idea for concurrent transactions

From: Ed Prochak <ed.prochak_at_magicinterface.com>
Date: Thu, 18 Mar 2004 08:03:45 -0500
Message-ID: <AJg6c.1183$%m4.177@fe03.usenetserver.com>

Paul wrote:

> mspight_at_dnai.com says...
>
>

>>>That sounds like it's much the same as MVCC, with the possible caveat
>>>of adding vulnerability to "dirty reads."

>
>
>
>

>>Anyone have any references to papers that describe MVCC? I've
>>never been able to dig up something that describes the approach
>>in enough detail that I could implement it. (I've read plenty of
>>gloss-over-the-details descriptions.)

>
>
>
> Two database systems that I know a bit about use MVCC (also called
> record shadowing or record versioning - I like the shadowing term
> myself).
>
> The two systems are Interbase/Firebird and PostgreSQL - if you look on
> www.ibphoenix.com at the docs section, you should be able to find stuff
> that is a bit more than "gloss-over-the-details". Also, on the
> PostgreSQL site, the docs there might be of help.
>
> I believe that Informix uses it, and also Oracle some of the time.
>
>
>
> Paul...
>
>
>

>>Marshall

>
>

Just an FYI, ORACLE has used Multiversioning for a LONG time. I believe they were the first to do it. At the time I first studied this, interbase was the only other DBMS to also used MV.

MV is why ORACLE is much better with large transaction volumes and many simultaneous sessions/connections than most other products. Locking is just a painful way of controlling access.

-- 
Ed Prochak
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--
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I took the one less travelled by
and that has made all the difference."
robert frost

Received on Thu Mar 18 2004 - 07:03:45 CST