Re: SQL/MED spec for cross-database linkages

Tom Lane wrote:
> Joe, have you heard of a standard called SQL/MED?  I came across a
> description of it the other day.  You might think it's got some medical
> connotation, but actually the acronym is Management of External Data,
> and what it is is a standard spec for shipping chunks of SQL queries to
> remote servers.  For instance, given
> 
>     SELECT * FROM a.foo, b.bar WHERE ...
> 
> where a.foo is on a remote machine, the spec lays down how the local and
> remote servers can cooperate to execute this query intelligently ---
> including deciding where to execute various WHERE clauses to minimize
> the amount of data shipped.  (The article I found was actually about
> how the new draft version of SQL/MED improves the protocol to let this
> sort of thing be done better; it seems the original spec only allowed
> retrieval of a whole table's contents.)
> 
> This looks like it might be a great long-term replacement for dblink,
> and if it is standard, so much the better.

Great! Thanks for the heads up. I see that Rod provided the reference in his 
post -- I'll go find it.

The idea of expanding dblink to other RDBMSs is picking up steam. I've been 
conversing off list with someone who has a semi-working hacked version of 
dblink that uses JDBC in place of libpq.

Do you think a proposal based on the SQL/MED spec would be entertained for 
7.4, or would the release after be a safer bet? I'm not sure (since I haven't 
seen it yet) what I'm getting myself into ;-), but I might like to take it on 
since there seems to be a lot of interest.

Joe


Joe