ignite-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From 胡永亮/Bob <hu...@neusoft.com>
Subject Re: Re: SQL join query return different result under the same data when having different ignite instance.
Date Wed, 27 Jul 2016 01:18:39 GMT
Hi  Val,

    My query is complex, I use another example to descripte my scenario.

    There are three objects: School, Class, Student.

    School:
    
id 
 name
 address
 1
 xxx
 aaa

  Class:
id 
 name
 number
 1
 yyy
 bbb

   Student:
id 
 name
 sex
 schoolID
 classID
 1
 zzz
 male
 1
 1

Now, the question is coming:
I want to query as the following sql: 
select * from school, class, student where student.id = school.id and student.id = class.id;

It means, the object student produced two affinity column: schoolID and classID, but as you
said:
"Generally that's right, you can collocate by a single field only, otherwise
the data will end up on different nodes"

How to do for this scenario? 



Bob
 
From: vkulichenko
Date: 2016-07-23 03:08
To: user@ignite.apache.org
Subject: Re: Re: SQL join query return different result under the same data when having different
ignite instance.
Hi Bob,
 
It's hard to tell how to collocate your data because it's not clear what
this query is doing. Can you describe?
 
Generally that's right, you can collocate by a single field only, otherwise
the data will end up on different nodes. If the data in two caches can't be
collocated, you can also switch one of the caches to REPLICATED mode.
Replicated caches don't need collocation, but they replicate all the data to
all nodes.
 
-Val
 
 
 
--
View this message in context: http://apache-ignite-users.70518.x6.nabble.com/SQL-join-query-return-different-result-under-the-same-data-when-having-different-ignite-instance-tp6433p6478.html
Sent from the Apache Ignite Users mailing list archive at Nabble.com.


---------------------------------------------------------------------------------------------------
Confidentiality Notice: The information contained in this e-mail and any accompanying attachment(s)
is intended only for the use of the intended recipient and may be confidential and/or privileged
of
Neusoft Corporation, its subsidiaries and/or its affiliates. If any reader of this communication
is
not the intended recipient, unauthorized use, forwarding, printing,  storing, disclosure or
copying
is strictly prohibited, and may be unlawful.If you have received this communication in error,please
immediately notify the sender by return e-mail, and delete the original message and all copies
from
your system. Thank you.
---------------------------------------------------------------------------------------------------
Mime
View raw message