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Date: Mon, 24 Feb 2014 10:20:07 -0500
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Subject: Are indexes replicated to all nodes?
From: Peter Lin <woolfel@gmail.com>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
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I was looking at the indexing code in Cassandra server and couldn't
determine if the indexes use the same replication factor as the keyspace.
When I print out the details of the keyspace, it correctly show the
replication factor, which "suggests" the index for a given partition only
lives on the same node.

I ask for a couple of reasons. Sometimes, users may want to be able to run
queries like these.

select * from MyColumnFamily where Column1='some1' or Column4='other1'

select * from MyColumnFamily where Column2 like '%OOP%' and Column5 like
'%architect%'

In our tooling, we've integrated Solr, so that we can do queries like this
with our query API. The query API looks like JPA/Hibernate, so we off load
the work to Solr when needed. If the indexes were replicated to all nodes
(aka partitions), Cassandra server could then use index joins and return
the results to the client.  The client can then merge the results.

What we do now is we query Solr to get the list of keys and then query
cassandra for the records by key.

anyone know the answer off hand?

thanks

peter

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<div dir=3D"ltr"><div><div><div><div><div><br></div>I was looking at the in=
dexing code in Cassandra server and couldn&#39;t determine if the indexes u=
se the same replication factor as the keyspace. When I print out the detail=
s of the keyspace, it correctly show the replication factor, which &quot;su=
ggests&quot; the index for a given partition only lives on the same node.<b=
r>
<br>I ask for a couple of reasons. Sometimes, users may want to be able to =
run queries like these.<br><br>select * from MyColumnFamily where Column1=
=3D&#39;some1&#39; or Column4=3D&#39;other1&#39;<br><br></div>select * from=
 MyColumnFamily where Column2 like &#39;%OOP%&#39; and Column5 like &#39;%a=
rchitect%&#39;<br>
<br></div>In our tooling, we&#39;ve integrated Solr, so that we can do quer=
ies like this with our query API. The query API looks like JPA/Hibernate, s=
o we off load the work to Solr when needed. If the indexes were replicated =
to all nodes (aka partitions), Cassandra server could then use index joins =
and return the results to the client.=A0 The client can then merge the resu=
lts.<br>
<br></div><div>What we do now is we query Solr to get the list of keys and =
then query cassandra for the records by key.<br></div><div><br></div>anyone=
 know the answer off hand?<br><br></div>thanks<br><br>peter<br></div>

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