[Zope] Re: updating catalog takes forever (never really completes)

Andreas Kostyrka andreas@kostyrka.priv.at
28 Sep 2002 13:10:46 +0200


Am Die, 2002-09-24 um 16.05 schrieb Luca Olivetti:

> > Basically: Yes it's reduant data. And yes we all learned that reduant
> > data is bad at University. Well, and some of us learned in the
> > real-world that sometimes reduant data is not bad at all :)
> > Especially in this case, as it is just an cache, that can be
> > automatically validated.
> 
> Automatically validated, yes, automatically generated/maintained, no, 
> it's an additional burden to the programmer.
That depends upon your objects. If you store your data in the right data
container, it's maintained automatically. If you intend to catalog your
data, I'd consider to store it in something CatalogPathAware, like my
FlexDatas (http://www.zope.org/Members/yacc/FlexData/)

> 
> > 
> > Well, OTOH, perhaps your are that pure in your thinking, ...
> > But then you should turn of the CPU caches off too, that is reduant data
> > too. (And with write back caches it's not even reduant data that is NOT
> > IN SYNC!)
> 
> In an ideal world these would be considered as ugly workarounds for 
> something that's either too slow or to expensive to achieve (and, BTW, 
> most of these are transparent to the programmer, while the addition and 
Not really. That's quite inexact. Take a class about Numerics and you
will discover that caches are not transparent at all.
Or take a look at the Linux kernel which has to deal with different
kinds of caches, ...

So talking about caches as being transparent is an oversimplification
that is ok for an introduction, but it can bite you quite awesome if you
forget about it.

> use of metadata to the index is not).
> OTOH I know we don't live in an ideal world, though I like to dream ;-)
Well, that's the nice thing about university. :)
And well, it's the unnice thing about real world :(

Andreas
-- 
Andreas Kostyrka <andreas@kostyrka.priv.at>