Bitmaps are a compact data structure in Redis that store boolean values to save memory space. They are useful for applications needing real-time analytics on large datasets like MOOCs. Bitmaps map boolean values to bits and support bitwise operations through commands like SETBIT, GETBIT, and BITCOUNT. While sets are easier to use for smaller datasets, bitmaps are better suited for domains with more than 232 bits due to their compact memory storage.

1. Bitmaps
Introduction to Redis Data Structures:

2. What is Redis?
Open Source, NoSQL Database
Used by: Twitter, Pinterest, GitHub
Stores Advanced Data Structures
Client Support: Java, C, Node.js etc
Introduction to Redis Data Structures: Bitmaps

3. What are Bitmaps?
Also called Bit Arrays/Vectors
Helps map boolean information into a compact representation
Widely used when memory space is a premium
Largest Domain Support: 232 bits
Introduction to Redis Data Structures: Bitmaps

4. Common Use Cases for Bitmaps
Provide extreme savings when storing
information
Real Time Analytics (GetSpool Blog)
Large size MOOC
Space Efficient, High Performance
Boolean InformationIntroduction to Redis Data Structures: Bitmaps

5. Bit Operations in Redis
SETBIT
GETBIT
BITOP
BITCOUNT
BITPOS
Introduction to Redis Data Structures: Bitmaps

6. Internal Implementation
Redis strings are implemented as Binary
Safe Strings
Internally called Simple Dynamic String
(SDS)
native char[]
More Details hereIntroduction to Redis Data Structures: Bitmaps

7. Redis Sets vs Redis Bitmaps
Sets are easier to manage,
program & debug
Work well for most apps
Small to medium size data
structures
> 232 Bits Domain SizeIntroduction to Redis Data Structures: Bitmaps
Bitmaps are suitable over a large
number of keys
Depends on size & performance
of keys

8. Summary
Redis Bitmaps provide Useful & Powerful functionality when memory space is a
premium
Not supported directly but in the form of Redis Strings
Best for platforms that need real-time analytics and huge data sets likes
MOOCs
Prefer Redis Sets for Simple ScenariosIntroduction to Redis Data Structures: Bitmaps

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