Aaron Stannard and Caglar Oner, founding engineers at MarkedUp Analytics (www.markedup.com), on how they use Cassandra, Hive, and Solr to create real-time reports for hundreds of customers under burst loads. Learn how to take advantage of Cassandra schema design, counter columns, Hive analysis, and Solr indexing to create robust, scalable analytics solutions. This talk was presented at the Los Angeles Cassandra Users meetup (http://www.meetup.com/Los-Angeles-Cassandra-Users/events/104649892/) on March 12, 2013

1. Real Time Analytics
LA Cassandra User’s Group
with Cassandra, Hive,
and Solr
By Aaron Stannard
and Caglar Oner March 2013

2. What is MarkedUp?
2
MarkedUp: powerful analytics
tools for native apps.
Understand your Monitor your Drive
audience. app’s health. more sales.
Gain valuable data on Log errors and crashes Better data = more
your users. remotely. revenue.

3. What Our Customers See
3

4. The Analytics CAP Theorem - SCV
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5. SCV Examples
5

6. The Truth about Analytics
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Real time analytics isn’t
inherently superior or
necessary.

7. Analytic Speed is a Business Decision
7

8. MarkedUp is a Blend of Both
8

9. Why Cassandra for Real Time?
9

10. Our Technology Stack
10

11. Cassandra Setup on EC2
11

12. Schema Strategy
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13. Write Strategy
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14. Read Strategy
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15. Time Series Schema 0: All Knowns
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16. Time Series Schema 1: Bounded Number of Unknowns
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17. Time Series Schema 2: Unbounded Number of Unknowns
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18. Schema Design Considerations
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19. Data, data and more data
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More Data = More Problems
• Every day is our peak day.
• Every day we sign up more apps and our apps sign up more users.

20. How Do We Manage this Data?
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TM
TM
TM
TM
TM

21. Managing a Cluster
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22. Hadoop Overview
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TM
• Two components:
• HDFS
• Map / Reduce
• Mimics Google File System and Map / Reduce
TM
• Started by Yahoo!
TM
• Part of Apache Foundation
• Mature and has rich ecosystem
• Scalable
• Highly available
• SLOOOOOWW

23. Hive Overview
23
TM
• A SQL Map / Reduce abstraction
• Originally developed as a BI tool for data warehousing @ Facebook
TM
• Rich data types (structs, lists and maps)
• Efficient implementation of joins, group-by's
• Scalable – easy to shard across nodes
• Tunable performance
• Extensible

24. Hive in Production
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• Simple Aggregations
SELECT applicationId, COUNT(1) AS dataPoints FROM
ApplicationTable
GROUP BY applicationId WHERE date = “2013-03-12”
• Data Mining
User Retention
User Engagement
• Ad hoc Analysis
How many sales by X?

25. Hive Syntax
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Query: count the number items where “key” is greater than 100
RDBMS> select key, count(1) from kv1
where key > 100 group by key;
Hive> select key, count(1) from kv1
where key > 100 group by key;

26. Hive Tables vs. Cassandra Column Families
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• When working with Cassandra, Hive still requires its own tables
• These are stored in HDFS typically
• In DataStax Enterprise Edition it’s implemented into a dedicated
TM
Cassandra key space
• Hive tables are mapped directly onto Cassandra column families

27. Mapping Hive to Cassandra
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CREATE EXTERNAL TABLE AverageTime (rowkey binary, dates bigint, total bigint)
STORED BY 'org.apache.hadoop.hive.cassandra.CassandraStorageHandler'
WITH SERDEPROPERTIES ("cassandra.ks.name" = “myKeySpace","cassandra.cf.name" =
“myColumnFamily", "cassandra.columns.mapping" = ":key, :column, :value" )
TBLPROPERTIES ( "cassandra.range.size" = "100", "cassandra.slice.predicate.size" = "100" );

28. Writing from Hive to Cassandra
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INSERT OVERWRITE TABLE AverageTime
SELECT secondQuery.Project, secondQuery.SessionDay, AVG(secondQuery.SessionSum)
FROM
(
SELECT firstQuery.Project, firstQuery.SessionDay, SUM(firstQuery.SessionLength) as
SessionSum FROM
(
SELECT HSessions.Project as Project, HSessions.Day as SessionDay,
HSessions.Length as SessionLength, HSessions.User as UserId
FROM HSessions
) firstQuery
GROUP BY firstQuery.Project, firstQuery.SessionDay, firstQuery.UserId
) secondQuery
GROUP BY secondQuery.Project, secondQuery.SessionDay;

29. Hive User-Defined Functions
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# export
HIVE_AUX_JARS_PATH=/home/user/scripts
# custom function
hive> create temporary function myFunc as
'com.markedup.hive.udf.Compositor';
SELECT myFunc(Apps.AppId, “DailySessions”) FROM
Apps WHERE ….

30. Hive Tips and Tricks
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• Don’t write data from Hive back to a hot Cassandra column family
• Created dedicated Cassandra column families for Hive
• You can write to multiple places on a single Hive read
• Use sampling to test Hive queries on scaled-down data sets

31. Solr
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TM
• Solr: Lucene-based indexing engine
• Part of Apache Foundation
• Full-text search
• Faceted search
• Distributed
• Integrates well with Cassandra

32. Real World Example
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How do you count a billion
distinct items in real-time?

33. Solr Index Setup
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34. Solr Search
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35. We Are Hiring!
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We’re hiring.
markedup.com/jobs

36. THANK YOU
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Questions? markedup.com
team@markedup.com