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Subject: Re: "select * from A join B using(common_id) where A.id == a and B.id
 == b "
From: aaron morton <aaron@thelastpickle.com>
In-Reply-To: 
 <CAAnh3_-bhgmMqM5v75Tx64FHrT1B4_jjnxk1RjEv05dd+1Z7Hg@mail.gmail.com>
Date: Mon, 25 Jul 2011 10:42:12 +1200
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References: 
 <CAAnh3_-bhgmMqM5v75Tx64FHrT1B4_jjnxk1RjEv05dd+1Z7Hg@mail.gmail.com>
To: user@cassandra.apache.org

> my fall-back approach is, since A and B do not change a lot, I'll
> pre-generate the join of A and B (not very large) keyed on A.id +
> B.id,
> then do the get(a+b)

+1 materialise views / joins you know you want ahead of time. Trade =
space for time.=20

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 23 Jul 2011, at 10:41, Yang wrote:

> this is a common pattern used in RDMS,
> is there some existing idiom to do it in cassandra ?
>=20
>=20
> if the size of "select * from A where id =3D=3D a " is very large, and
> similarly for B, while the join of A.id =3D=3D a and B.id=3D=3Db is =
small,
> then doing a get() for both and then merging seems excessively slow.
>=20
>=20
> my fall-back approach is, since A and B do not change a lot, I'll
> pre-generate the join of A and B (not very large) keyed on A.id +
> B.id,
> then do the get(a+b)
>=20
>=20
> thanks
> Yang