From: Tom Lane <tgl@sss.pgh.pa.us>
To: bruc@acm.org
Cc: pgsql-hackers@postgresql.org
Subject: Re: Are we losing momentum?
Date: Tue, 15 Apr 2003 19:18:24 -0400
Message-ID: <10857.1050448704@sss.pgh.pa.us> (raw)
In-Reply-To: <200304152254.h3FMsrwe047585@stone.congenomics.com>
References: <200304152254.h3FMsrwe047585@stone.congenomics.com>
"Robert E. Bruccoleri" <bruc@stone.congenomics.com> writes:
> I beg to differ with Tom Lane's opinion, but schemas do not solve the
> problem with multi-database queries because of the following reasons:
> 1) When dealing with large databases, the use of multiple databases
> reduces the risk of wiping out all the data, and reduces the recovery
> time in case of accidents.
> 2) Multiple databases allow for different management policies on each
> database, whereas schemas require some consistency across them all.
> In a heterogeneous working environment, this is a signficant issue.
> 3) PostgreSQL should strive for heterogeneous multi-database queries,
> so that applications currently using other systems could be slowly
> migrated to PostgreSQL by moving portions of a database from other
> vendors to PostgreSQL. In my work, the lack of PostgreSQL - Oracle
> connectivity is a disabling impediment to wider PostgreSQL usage.
Please keep in mind that I was replying to a poster who said "cross-db
queries on the same server (meaning same postmaster, for our purposes)
are trivial; why hasn't Postgres got them when everybody else does?"
Your above arguments are all good ones, but they presume a scenario that
is much different and *MUCH* harder to implement than local "cross
database" queries. My point is that schemas solve the same-server
problems that the original poster was interested in. I did not say,
nor mean, that there is no need for cross-server queries. But that is
a different problem. Today we can only offer dblink; maybe someday
SQL-MED.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, bruc@acm.org
Subject: Re: Are we losing momentum?
In-Reply-To: <10857.1050448704@sss.pgh.pa.us>
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