HyperLogLog
UV statistically independent
Cardinal number
Is the number of elements in the data base to set weight
HyperLogLog is used to make statistical base, using the algorithm LogLog
Basic Operations
- adding data
pfadd key element [element ...]- Statistical data
pfcount key [key ...]- Merge Data
pfmerge destkey sourcekey [sourcekey...]
Trips 22:
- redis applied to individual statistical information
Instructions
- Base for statistical, not a collection, do not hold data, only the number of records rather than specific data
- The core is the cardinality estimation algorithm, the final value of some errors
- Error range: Results cardinality estimate is 0.81% with a standard error of approximation
- Minimal consumption of space occupied by each htperloglog key 12k of memory for the marker base
- pfadd command is not a one-time allocation of 12k of memory use, will gradually increase with the increase in base memory
- Occupied by the merger of pfmerge command storage space for 12k, before merging the amount of data regardless of how much