Thread

Re: [GENERAL] Joins and links

Herouth Maoz <herouth@oumail.openu.ac.il> — 1999-07-05T13:49:58Z

At 15:46 +0300 on 05/07/1999, Leon wrote:


> ow can we radically improve performance in such cases? There
>  is a simple and quite obvious way. (For you not to think that
>  I am hallucinating I will tell you that there exist some
>  real servers that offer such features I am talking about)
>  We should make a real reference in one table to another! That
>  means there could be special data type called, say, "link",
>  which is a physical record number in the foreign table.
>
>  Queries could look like this:
>
>  table1:
>  a int4
>  b link (->table2)
>
>  table2:
>  c int4
>  recnum (system auxiliary field, really a record number in the table)
>
>  select * from table2 where table1.a > 5 and table1.b = table2.recnum
>
>  Such joins can fly really fast, as practice shows :)

If you are interested in such a feature, I would send it to the hackers
list and not the general list, which is not intended for development
issues, but for general problems and issues with existing versions.

The best would be, of course, to get hold of CVS and develop the needed
code yourself. That's what open software is all about. Perhaps if it's so
important to you, you could pay PostgreSQL incorporated, buying programmer
time for this feature.

In any case, a message to the hackers list may help you understand how
things are implemented in Postgres and how much work will be needed for
such a development. On the face of it, I can see several problems with this
idea, namely inefficiency in deletions, the need for fixed-length records
with no ability to add or drop columns or have variable-length fields
without maximum length, and needing to know all the tables that reference
a table for the sake of vacuuming. But maybe the hackers (who write
Postgres) would think differently. Ask them.

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma