RE: Secondary Indexes

[moshe.kranc]

I do not think this is a good use case for Cassandra alone, assuming the 
queries can be any combination of the 18 columns.
I would consider using some combination of Cassandra and Solr, where Solr 
provides the indexing/search, and Cassandra provides the bulk store.

From: Andy Stec [mailto:andys...@gmail.com]
Sent: Saturday, March 16, 2013 12:10 AM
To: user@cassandra.apache.org
Subject: Secondary Indexes

We need to provide search capability based on a field that is a bitmap
combination of 18 possible values. We want to use secondary indexes to
improve performance. One possible solution is to create a named column for
each value and have a secondary index for each of the 18 columns.
Questions we have are:


- Will that result in Cassandra creating 18 new column families,
one for each index?

- If a given column is not specified in any rows, will Cassandra
still create an index column family?

- The documentation says that indexes are rebuilt with every
Cassandra restart. Why is that needed? What does the rebuild do? Does it
read the whole column family into memory at once?
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Reading a counter column value

[Chidambaran Subramanian]

I created a CounterColumnType column family .

create column family counter1 with
 default_validation_class=CounterColumnType and replicate_on_write=true;

Unfortunately I could not figure out a way to read the column value. I am
using the Thrift API , and I couldn't make out any sense. I can't use
anything else right now, since I have a bunch of stuff already written
using Thrift. Any help is really appreciated.

Regards
Chiddu

MultiInput/MultiGet CF in MapReduce

[Alicia Leong]

Hi All

I have 2 tables

Data Table
-
RowKey: 1
= (column=name, value=apple)
RowKey: 2
= (column=name, value=orange)
RowKey: 3
= (column=name, value=banana)
RowKey: 4
= (column=name, value=mango)


Index Table (MMDDHH)

RowKey: 2013030114
= (column=1, value=)
= (column=2, value=)
= (column=3, value=)
RowKey: 2013030115
= (column=4, value=)


I would like to know, how to implement below in MapReduce
1) first query the Index Table by RowKey: 2013030114
2) then pass the Index Table column names  (1,2,3) to query the Data Table

Thanks in advance.

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[Jeffrey Fass]

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