Hello ShaoFeng Shi,
I tested this:
1) Joint Dimensions AB and joint dimensions AC -> while saving UI gives
error:
Error Message
Aggregation group 0 a dim exist in more than one joint
- Doesn’t say which dimension, but okay
I would raise question whether this is valid restriction, maybe this is too
strong limitation … ?? I can have i.e. one joint-dimension (date / customer)
and 2nd joint dimension (date / store) -> this way I am saying that I would
always analyze customers over time (or vice versa) and stores over time (and
vice versa) BUT never store over customer (or customer over store) – so to me
this seems to be beneficial to be able to improve the dimension pruning even
better …. Or ???
2) I also tried to put dimension A into mandatory dimension and then add
one joint dimension AC (I know it should mean that C is also mandatory), I got
this error while saving:
Error Message
Failed to deal with the request: null
Some some NPE occurred I guess – this seems to
be a bug for sure.
Thanx, Richard.
From: ShaoFeng Shi [mailto:[email protected]]
Sent: Friday, July 01, 2016 2:01 AM
To: [email protected]
Cc: Richard Calaba (Fishbowl) <[email protected]>
Subject: Re: Joint VS Derived
"joint" just tell Kylin to prune certain combinations; for example, "joint AB"
will prune all combinations that only has A or only has B; the order in "joint"
doesn't matter;
for case 3), it should not be allowed on Kylin's GUI, can you verify?
2016-07-01 14:47 GMT+08:00 Richard Calaba (Fishbowl) <[email protected]
<mailto:[email protected]> >:
Ok, so AB are joined, if:
1) Both A and B have to be specified in either in WHERE-clause or GROUP
BY-clause ; or one in WHERE and the other in GROUP-BY
2) The order of the Joint Dimension is or is NOT important ??? If AB is
joint, then BA is also joint, right?
Meaning "select ... group by B, A" or "select ... where B = xx group by A" is
also valid for AB as joint-dimension ???
3) If AB is joint and AC is joint:
a. It does NOT mean that ABC is necessarily joint group, right ???
b. Also BC doesn’t have to be joint, correct ??
Thanx, Richard.
From: ShaoFeng Shi [mailto:[email protected]
<mailto:[email protected]> ]
Sent: Thursday, June 30, 2016 7:45 PM
To: [email protected] <mailto:[email protected]>
Subject: Re: Joint VS Derived
This slide has introduction on the Derived Dim:
http://www.slideshare.net/YangLi43/design-cube-in-apache-kylin
"Joint" is introduced since 1.5.1; Using "joint" to combine multiple dimensions
into "one" ; Say if you have Dim A, B, C; among them AB are always appeared
together, e.g, "select ... group by A, B" or "select ... where A = xx group by
B"; in this case you can declare AB as "joint"; for Kylin it looks like a 2 dim
cube: AB, C, the combinations are decreased from 2^3 to 2^2;
2016-06-30 6:56 GMT+08:00 Alberto Ramón <[email protected]
<mailto:[email protected]> >:
Hi
I don't understand the difference between:
- Joint Dim (from Dimension Step )
- Derived Dim (from Advance Setings Step)
Some example ? :)
--
Best regards,
Shaofeng Shi
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Best regards,
Shaofeng Shi
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