Re: Lets get physical

From: Cimode <>
Date: 15 Jun 2006 12:12:21 -0700
Message-ID: <>

J M Davitt wrote:
> Cimode wrote:
> > paul c wrote:
> >
> >>Like some others here (as best as I can recall), I've puzzled over
> >>comments such as the TRM not being a physical layer.
> > Anybody who stated has not a clue about RM...What a stupid
> > comment...who advocated that? I certainly did'nt...
> >
> > Also, I noticed
> >
> >>recently that the last of the LZW patents is about to expire. Not that
> >>they're related but along with the latest jibe about physical matters,
> >>it gets me to thinking about implementations again.
> >
> >>From reading the patents information and observation, I have not found
> > anything related to hardware issues and their impact on implementation.
> > Only algoryhtmics explanations about representation and operations
> > have been exposed to the public...
> Are you referring to the TRM patent or the LZW patent?

What a stupid question...Since when a compression technology (LZW) is relevant to physical implementation in data management...I am speaking of TRM patent because paul brought it up...Duhh...

> >>I can accept the assertion about TRM as being a kind of indirection as
> >>long as I can envisage direct structures and algorithms for implementing
> >>it. TRM's ideas may well go deeper than I can express but what stuck
> >>with me about trying to implement it is that as far as deleting and
> >>insert are concerned the nature of OS storage allocation, whether on
> >>disk or in ram is such that lots of pointer chasing or re-allocation
> >>seems to be needed, if one avoids a "row-image" mapping. (When I say
> >>pointers, I don't necessarily mean the familiar 32 or 64 bit ones.)
> >
> > The problem is much more complex then simple mapping. It's about
> > faitful physical representation of a multidimensional relvars when
> > limits are imposed by current computing scheme involving
> "...involving" what?
Sorry typo meant "involved".

> >>In blunt terms, I couldn't see how a physical implementation of TRM
> >>could avoid having two values for some equivalent of pointers for each
> >>"row-column intersection", one to associate a value within a "row" or
> >>"tuple" and another to place it within some ordering. Not counting the
> >>values themselves, all those pointers seem to me to result in a physical
> >>size that is probably similar to one that used, say, a btree index for
> >>every column of a row-image table.
> >
> > That's my point...Anyway you turn it, physical implementation limit the
> > representation of a relvar...
> > Indexes are a secondary irrelevant issue. Building a better relational
> > DBMS supposes you just ignore that concept...
> >
> > Whether the indexes are sparse or
> >
> >>dense or whether they have shortcuts to avoid repeating identical values
> >>seemed irrelevant as far as comparing a TRM implementation with say, a
> >>so-called column-based store.
> >>
> >>What I read about TRM seemed to echo my impression, if only because of
> >>the two logical structures it gives.
> >>
> >>At the level or disk or ram, it seems to me that for a db of
> >>unpredictable size the usual fragmentation wastage will arise. (Also,
> >>depending on the number of columns, insert and delete time could be
> >>quite lengthy for an implementation that tries to minimize storage.)
> >>
> >>Finally, I wonder whether anybody has thought of implanting an LZW or
> >>other compression variation in conventional indexes
> >
> > A true relational DBMS has not indexes. Just ignore them. You think
> > too much in function of the SQL implementation and not enough in
> > function of RM?

> Who? paul? paul is thinking of SQL implementations?
Not only paul c but all the people who delude themselves thinking SQL is the same thing as RM. Indexes are just one consequence of SQL lack of support for RM concepts...

> >>Whether TRM is fundamentally a new idea or not doesn't seem to be a
> >>question that its proponents are going to give us an answer for. If
> >>somebody could show that at a physical level, it has no overriding
> >>advantages, I think that would be useful as I suspect there are others
> >>besides me for whom it would save time. Of course if somebody could
> >>show the opposite, that might be even more useful.
> >
> > TRM has brought some interesting insights on programmatics of
> > representation but not sufficiently about physical architecture
> > prerequisites. He has not dealt to the relatonship between
> > programmatic handling of datum and its efficiency on computing
> > architecture (CPU to RAM to Disk). Maybe these should be reconsidered
> > first...
> Okay, I'll bite: what are "programmatics of representation?"

The programmatic and computational mechanisms by which datum is represented and operated physically by some programming interface. On the information I had access to TRM has brought extensive innovation on that part but not enough on the relationship with the actual physical architecture. check discussion with paul c for further explanations...

> >>p
Received on Thu Jun 15 2006 - 21:12:21 CEST

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