NoSQL DatabasesOracle - Berkeley DB

Content

A brief intro to NoSQLAbout Berkeley DbAbout our application

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What is NoSQL?• Stands for Not Only SQL• Class of non-relational data storage systems• Usually do not require a fixed table schema nor do

they use the concept of joins, group by, order by and so on.

• All NoSQL offerings relax one or more of the ACID properties.

What is NoSQL ?• Next generation databases • Characteristic:– Large Data Volumes– Non-relational– Distributed– Open-source– Scalable replication and distribution

CAP Theorem

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History of NoSQL

• The term NoSQL was introduced by Carl Strozzi in 1998 to name his file based database.

• It was again re-introduced by Eric Evans when an event was organized to discuss open source distributed databases.

Why NoSQL Databases ?

• Bigness• Massive write performance• Fast key-value access• Flexible schema and Flexible data types• No single point of failure• Programming ease of use

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Scaling to size vs complexity.

Berkeley DB - Introduction

• An open-source, embedded transactional data management system.

• A key/value store.• Runs on everything from cell phone to large

servers.• Distributed as a library that can be linked directly

into an application.• Berkeley DB has high reliability and high

performance.

Berkeley DB Product Family Architecture

Berkeley DB: The Design Philosophy

• Provide mechanisms without specifying policies.• For example, Berkeley DB is abstracted as a store

of <key, value> pairs.– Both keys and values are opaque byte-strings.– Berkeley DB has no schema.– Application that embeds Berkeley DB is

responsible for imposing its own schema on the data.

Data Access Services

• Indexing methods– B-Tree– Hash– Queue– A record-number-based index

Advantages of <key, value> pairs

• An application is free to store data in whatever form is most natural to it.

– Objects (like structures in C language)– Rows in Oracle, SQL Server– Columns in C-store

• Different data formats can be stored in the same databases.

Data Management Services

ConcurrencyTransactionsRecovery

Berkeley DB Applications

• Local Directory Access Protocol• Mail Servers• Manage access control lists• Store user keys in a public-infrastructure• Record machine-to-network address

mappings in address servers

Berkeley DB for Computationally Intensive

Algorithms• Algorithms that repeatedly execute a

computationally intensive operation– E.g. Factorial

• Useful to create a cache containing the already computed results– Cache = Set of <key,value> pairs containing <n,

factorial(n)>

• Advantages:– avoid to re-compute results for the same input (even

over different executions) – In a process crash, we can still start again the process

and quickly go back to the point where it stopped

• In memory map• Simple• Very efficient (b/s in completely memory)• Need considerable amount of memory• No fault tolerance (We need to manually save data to a file)• Relation Databases• ACID properties may not be necessary• Cannot handle Big data • Slow• NoSQL databases (Berkeley DB)• Fast key-value access• Flexible schema and Flexible data types• Ease of use• Fault tolerance

Berkeleydb.java

• Open Environment:• EnvironmentConfig class specify environment configuration parameters

• Open Class Catalog: • Class catalog : specialized database store that contain

java class descriptions of all serialized objects stored in the database

• Create Database and StoredClassCatalog object

• Open Database:

• Close Environment, Class Catalog and Databases:

DBViews.java

Factorial.java

Factorial (Berkeley DB ) – Memory Usage

Factorial (MySQL) – Memory Usage

Factorial (HashMap) – Memory Usage