Re: logical column order and physical column order - Mailing list pgsql-hackers

From David Johnston
Subject Re: logical column order and physical column order
Date
Msg-id 1383491412523-5776784.post@n5.nabble.com
Whole thread Raw
In response to logical column order and physical column order  (David Rowley <dgrowleyml@gmail.com>)
List pgsql-hackers
David Rowley wrote
> I'm sure in the real world there are many cases where a better choice in
> column ordering would save space and save processing times, but is this
> something that we want to leave up to our users?

Right now there is little visibility, from probably 99% of people, that this
is even something to be concerned with.  I have no qualms with making a
person run a routine to change the physical ordering of their tables - and
if they really care about logical order in the output it is best to list the
column names anyway - so the problem that is worth solving is providing a
way for the system to tell the user, for a given table, what the most
efficient physical order would be - ideally in the form of a CREATE TABLE AS
statement - and let the user manually effect the change.

So invent the algorithm to identify the best physical order and make it
accessible to users for manual use.  If the benefits seem great enough after
its use for a couple of releases a more informed decision can be made as to
whether to try and automate its application.

David J.



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