UV is basic statistics. It's the document to improve the logic of UV using Redis Bitmap functions and hashmap.

1. UV Logic
using Redis Bitmap
Jooyong Oh
awesome2828@gmail.com

2. What we want?
● Periodical UV
○ daily
○ weekly
○ monthly
○ total
● UV by dimension
○ country
○ service

3. before logic
● traditional logic
○ make and maintain daily UV list
○ make weekly/monthly UV list using daily UV
Daily Logs
Daily UV
Daily UV
Daily UV
Daily UV
Weekly
UV
Monthly
UV
Total UV
UV by
country
UV by
service

4. before logic
● size is too large !!!
○ if daily UV is 50 million, and store (Date, User-ID, country, service),
we need about 55GB
● cannot support real-time UV !!!
● problem is...
○ “maintain” daily UV list
○ aggregate from “whole” daily logs

5. new logic
● Concept :
○ use Redis HashSet & Bitmap
○ maintain whole user HashSet
○ maintain daily bitmap
○ calcurate weekly, monthly, total UV with Bit
operation

6. new logic
Conceptual
diagram

7. new logic
Diagram
with real command

8. new logic
● When we need UV for a day,
we can get it with BITCOUNT command
> BITCOUNT UV_{YYYYMMDD}
● If we need for UV for n-day,
we can get it with BITOP, BITCOUNT command
> BITOP OR dest UV_{YYYYMMDD1} UV_{YYYYMMDD2} … UV_
{YYYYMMDDn}
> BITCOUNT dest

9. new logic
● The Bitmap name “UV_{YYYYMMDD}” can be extended
to “UV_service_{YYYYMMDD}” and “UV_country_
{YYYYMMDD}”
● When we need UV for ServiceA and CountryA, we can
get it with BITOP command
> BITOP AND dest UV_serviceA_{YYYYMMDD} UV_countryA_
{YYYYMMDD}
> BITCOUNT dest

10. Benefit of the new logic
● We can get UV for elastic period (last 3day, 4day or temporary
period)
● We can get UV in real-time
● Time complexity of Redis Bitmap operation is just O(1)
● It need very small memory for UV (1.5GB when total user is 1
billion.

11. Future work
● Redis Bitmap can cover to 2^32 (about 4
billion)
● If user count increased, this logic need to be
improved (shard would be one candidate)

12. Jooyong Oh
awesome2828@gmail.com
End of Slide