[Monetdb-developers] The new "ws-API", Algebra & XRpc (& PFtijah)

Stefan Manegold Stefan.Manegold at cwi.nl
Fri Oct 6 15:42:02 CEST 2006


On Fri, Oct 06, 2006 at 03:08:00PM +0200, Stefan Manegold wrote:
> On Fri, Oct 06, 2006 at 02:39:19PM +0200, Jan Rittinger wrote:
> > If this wsid is a concept that is strictly necessary for the update 
> > support (and nobody except me thinks that this bit shifting might be not 
> > the nicest solution) we could also think about getting rid of the ws and 
> > replacing it with the wsid. I just do not like the fact that there are 
> > two variables underway that have some side effects on each other.
> 
> To be honest, I'm still in the process of analyzing trying to understand,
> what all the flavors, pros, cons, and ideas behind having/using wsid are;
> hence, I cannot tell, whether it is "strictly necessary" or not.
> 
> As far as I understand so far, the basic idea behind the "bit shifting" is
> merely to store both the id of (and hence reference to) BAT ws as well as a
> unique identifier --- that is still valid after a query/transaction (and hence
> cannot simply be the ws BAT id, which might be re-used for a subsequent
> query/transaction) --- in one single atomic value.
> 
> Further, I agree, that having two related variables that need to be kept in
> sync and treated accordingly is not very handy for maintenance --- my guess
> is, that the current situation resulted from lack of time and fear to
> implement (something like) your (d) proposal; which I agree is "nicer" &
> "cleaner", but requires quite a lot of possibly error-prone code changes ---
> nevertheless, I might give it a try during the weekend ...
> 
> Stefan
> 
> > So a fourth proposal (d) would be to replace the occurrences of ws by 
> > wsid. This would mean that *all* document accesses would have to include 
> > another indirection (even all path steps).

Well, I just realize that this actually only helps to save us from having
function interfaces that expect/use either ws or wsid or both --- it does
not help to get rid of the global ws variable: to exist throught the whole
query, the ws BAT must either be a global variable or be persistent --- the
latter is not possible, since ws is a BAT-of-BATs, and those cannot be
persistent...

... I just recall, that we have something like "session" BATs --- I'll check
whether that's an option (any help/hint is of course welcome ...)

Stefan

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| Dr. Stefan Manegold | mailto:Stefan.Manegold at cwi.nl |
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