1. CS122B: Projects in Databases and Web Applications Winter 2017
Notes 07: NoSQL and Hadoop
Professor Chen Li
Department of Computer Science
UC Irvine
CS122B

2. NoSQL Very hot these days What does NoSQL mean?
Mainly with startups, less with enterprises
What does NoSQL mean?
“Not Only SQL” or “Not Relational”.

3. NoSQL: Overview
“A NoSQL database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases.”
Give up some of the ACID constraints to improve performance
Simple interface:
Write (=Put): needs to write all replicas
Read (=Get): may get only one

4. NoSQL Key features: Scale horizontally “simple operations”
Replicate/distribute data over many servers
Simple call level interface (contrast w/ SQL)
Weaker concurrency model than ACID
Efficient use of distributed indexes and RAM
Flexible schema

5. 1. Key-value Stores Think “file system” more than “database”
Put/get calls with a key
Voldemort, Memcached
Only primary index: lookup by key
No secondary indexes

6. 2. Document Stores
Nested values, extensible records (e.g., XML or JSON).
Schema-less
MongoDB, CouchDB
May have secondary indexes

7. 3. Column stores Data organized as columns, not rows
Vertica, HBase, Cassandra

8. 4. Scalable Relational Systems
Means RDBMS that offer sharding
MySQL Cluster, VoltDB

9. What is Hadoop?
Apache top level project, open-source implementation of frameworks for reliable, scalable, distributed computing and data storage.
It is a flexible and highly-available architecture for large scale computation and data processing on a network of commodity hardware.

10. Google Origins
2003
2004
2006

11. Word Count over a Given Set of Web Pages
see 1
bob 1
throw
see 1
spot 1
run 1
bob 1
run
see 2
spot 1
throw 1
see bob throw
see spot run
Can we do word count in parallel?

12. Word Count over a Given Set of Web Pages

13. “Big Data” Era