Thread: Trying to create multi db query in one large queries
Hi,
I am not sure if this is the place to ask this question, but since the
question is trying to improve the performance.. i guess i am not that
far off.
My question is if there is a query design that would query multiple
server simultaneously.. would that improve the performance?
To make it clear.. let's say we have 3 db servers. 1 server is just
designed to take the queries while the other 2 server is the ones that
actually
holds the data. let's say we have a query of 'select * from
customer_data' and we change it to
select * from
(
dblink('db1','select * from customer_data where timestamp between
timestamp \'01-01-2004\' and timestamp \'06-30-2004\'')
union
dblink('db2','select * from customer_data where timestamp between
timestamp \'01-07-2004\' and timestamp \'12-31-2004\'')
)
Would the subquery above be done simultaneously by postgres before doing
the end query? or would it just execute one at a time?
If it does execute simultaneously.. it's possible to create code to
convert normal queries to distributed queries and requesting data from
multiple
database to improve performance. This would be advantageous for large
amount of data.
Thanks,
Hasnul
Hasnul, > My question is if there is a query design that would query multiple > server simultaneously.. would that improve the performance? Not without a vast amounts of infrastructure coding. You're basically talking about what Oracle has spent the last 3 years and $100 million working on. Would be nice, though. -- Josh Berkus Aglio Database Solutions San Francisco
The world rejoiced as josh@agliodbs.com (Josh Berkus) wrote: > Hasnul, > >> My question is if there is a query design that would query multiple >> server simultaneously.. would that improve the performance? > > Not without a vast amounts of infrastructure coding. You're > basically talking about what Oracle has spent the last 3 years and > $100 million working on. I recall a presentation from folks from Empress Software <http://www.empress.com/> back in about '94 or '95 offering this very feature as part of the "base functionality" of their product. I'm not sure it's quite fair to assess things as "more or less preposterous" simply because they prove ludicrously expensive to develop on a particular platform that happens to be targeted by even more ludicrous quantities of development dollars... On the other hand, it seems unlikely that "improved performance" would be one of the merits of this approach... -- let name="cbbrowne" and tld="gmail.com" in String.concat "@" [name;tld];; http://www3.sympatico.ca/cbbrowne/ Rules of the Evil Overlord #92. "If I ever talk to the hero on the phone, I will not taunt him. Instead I will say that his dogged perseverance has given me new insight on the futility of my evil ways and that if he leaves me alone for a few months of quiet contemplation I will likely return to the path of righteousness. (Heroes are incredibly gullible in this regard.) <http://www.eviloverlord.com/>