Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!postnews.google.com!e56g2000cwe.googlegroups.com!not-for-mail
From: "vc" <boston103@hotmail.com>
Newsgroups: comp.databases.theory
Subject: Re: MV Keys
Date: 3 Mar 2006 14:34:09 -0800
Organization: http://groups.google.com
Lines: 38
Message-ID: <1141425249.779277.68060@e56g2000cwe.googlegroups.com>
References: <440185c0$0$11076$e4fe514c@news.xs4all.nl>
   <1140963712.820976.72300@u72g2000cwu.googlegroups.com>
   <4401cd8b$0$11062$e4fe514c@news.xs4all.nl>
   <1140981916.897576.34490@u72g2000cwu.googlegroups.com>
   <1141000908.277461.101140@t39g2000cwt.googlegroups.com>
   <MPG.1e6e1c576dad2a0298976b@news.ntnu.no>
   <1141180942.125742.288830@j33g2000cwa.googlegroups.com>
   <MPG.1e6f9e5a3f96c28d98976c@news.ntnu.no>
   <1141239957.788010.239620@j33g2000cwa.googlegroups.com>
   <1141260473.796686.131530@u72g2000cwu.googlegroups.com>
   <MPG.1e710d32cc86fa77989770@news.ntnu.no>
   <1141324828.479189.199000@i40g2000cwc.googlegroups.com>
   <MPG.1e72083e15dbf5e598977b@news.ntnu.no>
   <1141399209.093211.14150@z34g2000cwc.googlegroups.com>
   <4408783f$0$11076$e4fe514c@news.xs4all.nl>
   <1141406548.689358.288430@p10g2000cwp.googlegroups.com>
   <4408a6c7$0$11067$e4fe514c@news.xs4all.nl>
NNTP-Posting-Host: 24.91.127.140
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
X-Trace: posting.google.com 1141425254 12102 127.0.0.1 (3 Mar 2006 22:34:14 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Fri, 3 Mar 2006 22:34:14 +0000 (UTC)
In-Reply-To: <4408a6c7$0$11067$e4fe514c@news.xs4all.nl>
User-Agent: G2/0.2
X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50215),gzip(gfe),gzip(gfe)
Complaints-To: groups-abuse@google.com
Injection-Info: e56g2000cwe.googlegroups.com; posting-host=24.91.127.140;
   posting-account=thIdtgwAAAAhUVpIR1L4IFjCXWRKlxtG
Xref: dp-news.maxwell.syr.edu comp.databases.theory:37224


mAsterdam wrote:
> vc wrote:
> > mAsterdam wrote:
> >
> >>Marshall Spight wrote:
> >>
> >>>Jon Heggland wrote:
> >>>
> >>>The relational operators don't handle lists very well.
> >>>
> >>>myList.removeAt(3)
> >>>
> >>>vs.
> >>>
> >>>BEGIN
> >>>delete from MyList where Index = 3;
> >>>update MyList set Index = Index - 1 where Index > 3;
> >>>COMMIT
> >>
> >>
> >>Aside (the example surely illustrates your point)
> >>could this removeAt operation possibly be useful
> >>in a concurrent environment?
> >>
> >>You'ld never know which item you are going to scratch -
> >>somebody else could have just done myList.removeAt(2).
> >
> >
> > What happened to concurrency contro in your hypothetical system ?
>
> Assuming MVCC the item which was the third item
> in MyList at transaction time would be removed.
> Results may be very unpleasant - that was my point -
> but would this constitute a CC failure?

Sure it would.  It would mean that your database CC is broken.