Re: Explain-lite (Explain discussion)

Bob,

> 
> EXPLAIN is for clients.  My hope for EXPLAIN was that servers would be asked
> to populate fields that it had no idea why a client would want, and thus
> support client functionality beyond the common.   But even without this hope
> I wonder how you defined "common" - I only use 7 or 8 fields, I hope all and
> only those are "commonly used".
>   Z39.50 does have this ongoing problem of appearing complex - but in
> EXPLAIN like Z39.50 you can ignore all but what you actually need or care
> about - the rest is noise, and easy in this case to ignore...

but you still have the Explain search/retreival database model to create -
in most cases where  Z39.50 servers have only a single database this
model is a significant, complex overhead that is time consuming to add
after an Init. Explain lite is aimed at the cases where servers have
between 1 and several databases.

> 
> > I think that to re-invent explain in the context of its current model is
> > essentially a waste of time - the current model has been around for over 5
> > years now, it was seriously pushed by the ONE project, it was pushed
> > by the explain test bed and the number of implementations as far as I 
> > know is minimal. I dont see that changing the query syntax or
> > the ASN.1 definition of the record syntax is going to encourage a majority
> > of folk to think differently about implementing.
> 
> And XML is going to be different why??  TO me that is no different than a
> change to the ASN.1 definiton.
Because working in ASN.1 is not what our partners want to do  - people
want to work in XML - they dont want to work in ASN.1. XML by comparison
is easy, readable, flexible, has a wide range of supportting tools and it 
fits into corporate business and training models.

> 
> 
> > - our proposed use is to carry this as an XML external on the Init
> >   service means that none of the explain database or the explain querying
> >   has to be supported;
> 
> 
> I have alot of trouble with this.  So I have approx 300 databases, all with 
> their own layout.  I send this everytime to every client? CHecked - it is
> 12 Meg.  And note my "common" is probably smaller than yours - certainly
> BER/ASN.1 is smaller than XML.  And no caching - since doing it in init?
>   I always thought this was a clever part of the EXPLAIN model - clients
> ask for just what they need.

It is a negotiated model - the content is what our cliehnts need, and as
Sebastian mentioned, is date stamped.

But, I would gauge that the amount of data to transfer regarding a 300
database system in the explain model with search/present requests and
responses is going to be very significant as well.

By comparison, the amount of data on a single database system, or a system
with a few databases is very similar.

Rob

Received on Friday, 17 November 2000 06:25:58 UTC