Redis does web page UV statistics

Foreword

First of all, we must understand what UV is, that is, independent visitor records (the same user visits the same page multiple times, and only counts the page has been visited once by this user), which requires the redis data type we use to have a deduplication function.It is recommended to use HyperLogLog implementation

Use set to achieve

Assume user 1 visits page A three times

# 1 for user idsadd A:20220801 1sadd A:20220801 1sadd A:20220801 1

Statistical UV of page A

# UV = 1scard A: 20220801

Use hash to achieve

Assume user 1 visits page A three times

# The last 1 can also be filled with others, it is only used as a placeholderhset A:20220802 1 1hset A:20220802 1 1hset A:20220802 1 1

Statistical UV of page A

# UV = 1hlen A: 20220802

Implementation with HyperLogLog

The advantage of HyperLogLog is that when the number or volume of input elements is very, very large, the space required to calculate the cardinality is always fixed and small.

Assume user 1 visits page A three times

# Add three 1s at a timepfadd A:20220803 1 1 1

Statistical UV of page A

# UV = 1pfcount A: 20220803