Subject: Re: ingres and atomicity
To: None <>
From: James K. Lowden <>
List: tech-userlevel
Date: 06/13/2005 21:07:04
Christos Zoulas wrote:
> In article <>,
> James K. Lowden <> wrote:
> >Back to the future: Ingres is free again.  If you google "ingres
> >" you get a lot of messages about the group, and some
> >ancient ones about the original RDBMS from Berkeley.  You may know CA
> >released it as open source.  I thought I'd try my hand at porting it. 
> >Since going commercial, Ingres grew threads, about which it seems I'll
> >have to learn.  
> >
> >My first real difficulty has to do with "atomic clear".  The build
> >requires it:
> >
> >ingres/src/cl/hdr/hdr_unix_win/csnormal.h:2621:11: 
> >	#error : must define an atomic clear
> I think that the best way to make progress is to follow what Linux
> does, and mark it XXX:jkl or something where you need to re-visit it.

Ah, I did that, and the waters got immediately murkier.  So I backed off
and decided to *understand* the issues, however hard that might be.  

Does the term "atomic clear" have some generally accepted meaning, or is
it  Ingrespeak?  

Do we support, anywhere, the idea of changing a word (4 bytes) of memory
atomically, meaning that no other thread can intervene?