Redis (V) - advanced data types

Redis（ 5、 ... and ）—— Advanced data types

1、Bitmaps

Basic operation

• Get specified key Corresponding to... On the offset bit value

  getbit key offset
  

• Set the specified key Corresponding to... On the offset bit value ,value Can only be 1 or 0

  setbit key offset value
  

Extended operation

• Specify key Hand in by position 、 and 、 Not 、 Exclusive or operation , And the result Save to destKey in

  bitop op destKey key1 [key2...]
  

  • and： hand over
  • or： and
  • not： Not
  • xor： Exclusive or

• Specify Statistics key in 1 The number of

  bitcount key [start end]
  

2、HyperLogLog

base

• Cardinality is the data set Number of elements after de duplication
• HyperLogLog It is used for cardinality Statistics , Use of the LogLog The algorithm of

Basic operation

• Add data

  pfadd key element1, element2...
  

• statistics

  pfcount key1 key2....
  

• Merge data

  pfmerge destkey sourcekey [sourcekey...]
  

Related instructions

• Used for cardinal Statistics , It's not a collection , Don't save data , Just record the quantity, not the specific data
• The core is the cardinality estimation algorithm , Final value There are some errors
• Error range ： The result of cardinality estimation is a function with 0.81% Approximate value of standard error
• Minimal space consumption , Every hyperloglog key Occupied 12K Memory used to mark cardinality
• pfadd Command is not a one-time assignment 12K Memory usage , As the cardinality increases, memory Gradually increase
• Pfmerge command Occupied after consolidation The storage space of is 12K, Regardless of the amount of data before merging

3、GEO

Basic operation

• Add coordinate points

  geoadd key longitude latitude member [longitude latitude member ...] 
  georadius key longitude latitude radius m|km|ft|mi [withcoord] [withdist] [withhash] [count count]
  

• Get coordinate points

  geopos key member [member ...] 
  georadiusbymember key member radius m|km|ft|mi [withcoord] [withdist] [withhash] [count count]
  

• Calculate the distance between coordinate points

  geodist key member1 member2 [unit] 
  geohash key member [member ...]