Redis DSA

geo.sh

# Adding coordinates <longitude, latitude>
# Longtude Degree horizontal (east)
# Latitide Degree vertical (North)
GEOADD gpo 77.5839739 12.910647 "Home"
GEOADD gpo 77.6965459 12.939111 "SLV Residency"
GEOADD gpo 77.6102169 12.935152 "Forum Mall"
GEOADD gpo 77.5964085 12.91486 "Freshco Supermarket"
GEOADD gpo 77.64062 12.892286 "Myntra Designs Pvt Ltd"

# Stored as sorted set
# Score is computed geohash of the point
ZRANGE gpo 0 -1 withscores

# Get Geohash
# 11 char representation of stored hash, Confirms to GeoHash Standard
# Interoperability with other systems and services
# Truncation causes inaccuracy, but not byh much
geohash gpo "Home" "SLV Residency"
1) "tdr1mqqcvw0"
2) "tdr3852zu90"

# Getting stored coordinates
geopos gpo "Home" "SLV Residency"
1) 1) "77.58397132158279419"
   2) "12.91064658271323395"
2) 1) "77.69654363393783569"
   2) "12.93911150133261145"

# Finding distance between two locations in same key
geodist gpo "Home" "Freshco Supermarket"
"1427.2017"
geodist gpo "Home" "Freshco Supermarket" "km"
"1.4272"
geodist gpo "Home" "Myntra Designs Pvt Ltd" "km"
"6.4724"
geodist gpo "Home" "Forum Mall" "km"
"3.9404"
geodist gpo "Home" "SLV Residency" "km"
"12.6078"

# Searching for locations within given radius of Jaydeva Junction
# With coordinates, distance and hash in ascending order of distance
GEORADIUS gpo 77.599670 12.916655 2 km withcoord withdist withhash asc
1) 1) "Freshco Supermarket"
   2) "0.4063"
   3) (integer) 3574451358640845
   4) 1) "77.59640604257583618"
      2) "12.91485928928005222"
2) 1) "Home"
   2) "1.8284"
   3) (integer) 3574451331983601
   4) 1) "77.58397132158279419"
      2) "12.91064658271323395"

# Desc example
GEORADIUS gpo 77.599670 12.916655 4 km withcoord withdist withhash desc
1) 1) "Forum Mall"
   2) "2.3539"
   3) (integer) 3574451926733187
   4) 1) "77.61021941900253296"
      2) "12.93515226688172248"
2) 1) "Home"
   2) "1.8284"
   3) (integer) 3574451331983601
   4) 1) "77.58397132158279419"
      2) "12.91064658271323395"
3) 1) "Freshco Supermarket"
   2) "0.4063"
   3) (integer) 3574451358640845
   4) 1) "77.59640604257583618"
      2) "12.91485928928005222"

# Farthest within radius
GEORADIUS gpo 77.599670 12.916655 4 km withcoord withdist withhash count 1 desc
1) 1) "Forum Mall"
   2) "2.3539"
   3) (integer) 3574451926733187
   4) 1) "77.61021941900253296"
      2) "12.93515226688172248"

# GEORADIUSBYMEMBER does same thing just by named member, so the member is at center of that radius
# hence always included in result
GEORADIUSBYMEMBER gpo "Forum Mall" 3 km WITHCOORD WITHDIST WITHHASH ASC
1) 1) "Forum Mall"
   2) "0.0000"
   3) (integer) 3574451926733187
   4) 1) "77.61021941900253296"
      2) "12.93515226688172248"
2) 1) "Freshco Supermarket"
   2) "2.7087"
   3) (integer) 3574451358640845
   4) 1) "77.59640604257583618"
      2) "12.91485928928005222"

hash.sh

# Setting multiple fields
hset event:judo capacity 12000 location "Dumbass Arena" ticket_price:gold 100 availability:gold 100
(integer) 0
# Setting single field
HSET event:judo availability:gold 8000
(integer) 0
# Check if key exists
HEXISTS event:judo location
(integer) 1
HEXISTS event:judo place
(integer) 0
# Get all fields, not good for performance
HGETALL event:judo
 1) "capacity"
 2) "12000"
 3) "location"
 4) "Dumbass Arena"
 5) "ticket_price:gold"
 6) "100"
 7) "availability:gold"
 8) "8000"
 9) "availability:silver"
10) "2000"

# Using scan
HSCAN event:judo 0 match availability:*
1) "0"
2) 1) "availability:gold"
   2) "8000"
   3) "availability:silver"
   4) "2000"

keys.sh

# Number of keys present in cache
dbsize

# SET Command
# SET <key> <value> [EX seconds] [PX milliseconds] [NX] [XX]
# NX - set only if doesn't exist, XX set only if exist
# returns OK if executed correctly

SET customer:1000 fred
SET customer:1500 jane

# Get key values
GET customer:1000

# KEYS and SCAN
# KEYS command return keys matching pattern
# good for debugging, not prod
KEYS customer:1*

# SCAN command (Cursor based iterator)
# An iteration starts when the cursor is set to 0, and terminates when the cursor returned by the server is 0
SCAN 0
# keep using slot index to move forward cursor for next iteration
# O(1) per call with linear iteration
# can be used in prod with downside like KEYS
# MATCH and COUNT are optional
scan 4644 MATCH customer:1* COUNT 1000

# Deleting keys (and cleans up memory)
# can take O(M) of hash set deletion etc
# Blocking call, returns number of deleted keys
# can accept multiple keys to be deleted
DEL customer:1000

# UNLINK
# Non blocking O(1)
# Similar to DEL, deletes key
# but memory reclaim happens async in another thread
UNLINK customer:1500

# More Examples
127.0.0.1:6379> set inventory:100-meters-women-final 1000 NX
OK
127.0.0.1:6379> set inventory:100-meters-women-final "Sold Out" NX
(nil)
127.0.0.1:6379> set inventory:100-meters-women-final 0 XX
OK
127.0.0.1:6379> get inventory:100-meters-women-final

list.sh

# List in redis is doubly linked list implementation
LPUSH wins:2019 ham:9 vet:1 lec:2
(integer) 3
LLEN wins:2019
(integer) 3
LRANGE wins:2019 0 -1
1) "lec:2"
2) "vet:1"
3) "ham:9"
RPOP wins:2019
"ham:9"
LPOP wins:2019
"lec:2"
LRANGE wins:2019 0 -1
1) "vet:1"

pubsub.sh

# Subscribing to single/multiple channels
SUBSCRIBE dax
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "dax"
3) (integer) 1
1) "message"
2) "dax"
3) "hello"
^C
# Multiple channels
SUBSCRIBE ch1 ch2
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "ch1"
3) (integer) 1
1) "subscribe"
2) "ch2"
3) (integer) 2
1) "message"
2) "ch1"
3) "fp1"
1) "message"
2) "ch2"

# Publish Messages
# Returns no. of clients that received the message
PUBLISH ch1 fp1
(integer) 1
PUBLISH ch2 rossi
(integer) 1
PUBLISH ch3 mock
(integer) 0

# ---
# Pattern based subscription
PSUBSCRIBE ch-*

# Admin Commands
# Get list of subscribed channels
PUBSUB channels
# Number of subscribed by fixed channel
PUBSUB numsub ch-1 ch-2
# Pattern subscribers
PUBSUB numpat ch-*

set.sh

# Creating set
SADD drivers "ham" "vet" "lec" "ver" "ric"
(integer) 5
# good for test and development, scan better for prod
SMEMBERS drivers
1) "lec"
2) "vet"
3) "ver"
4) "ham"
5) "ric"
sscan drivers 0 match *
1) "0"
2) 1) "lec"
   2) "vet"
   3) "ham"
   4) "ver"
   5) "ric"
sscan drivers 0 match v*
1) "0"
2) 1) "vet"
   2) "ver"
   
# Check Set membership
SISMEMBER drivers "vet"
(integer) 1
SISMEMBER drivers "mag"
(integer) 0

# Removing elements which exist (or not exist)
# Not exist
SREM drivers "mag"
(integer) 0
# Exist
SREM drivers "ric"

# Remove two random elements
SPOP drivers 2
1) "vet"
2) "lec"
(integer) 1

# SET operations
sadd ferrari "vet" "rai" "lec" "alo" "shu"
(integer) 5
sadd mclaren "nor" "alo" "sai" "ham"
(integer) 4
sadd mercedes "ham" "ros" "shu" "bot"
(integer) 4
SINTER ferrari mclaren
1) "alo"
SINTER ferrari mercedes
1) "shu"

sortedset.sh

zadd standings 413 ham 326 bot 278 ver 264 lec 240 vet 96 sai
(integer) 6
zrange standings 0 -1
1) "sai"
2) "vet"
3) "lec"
4) "ver"
5) "bot"
6) "ham"
# By rank, which is 0 based
zrange standings 0 2
1) "sai"
2) "vet"
3) "lec"

zrange standings 0 2 WITHSCORES
1) "sai"
2) "96"
3) "vet"
4) "240"
5) "lec"
6) "264"
# Getting score of a specific element
ZSCORE standings vet
"240"
# Getting rank of a element
ZRANK standings vet
(integer) 1

# Getting count if elements in given score range
ZCOUNT standings 250 420
(integer) 4
# Getting element itself
ZRANGEBYSCORE standings 250 420
1) "lec"
2) "ver"
3) "bot"
4) "ham"
# Removing
zrem standings sai
(integer) 1
zrange standings 0 -1
1) "vet"
2) "lec"
3) "ver"
4) "bot"
5) "ham"

strings.sh

# any type of values can be stored as string data type (text, numbers, binary data)
# limit of 512 MB with value
# type is checked before any command operates on value

set races:pole:mercedes 12
OK
get races:pole:mercedes
"12"
# Type is mostly string for plain values
TYPE races:pole:mercedes
string
# works because object encoding is integer
DECRBY races:pole:mercedes 1
(integer) 11
get races:pole:mercedes
"11"
TYPE races:pole:mercedes
string
object encoding races:pole:mercedes
"int"
# changing value to string
set races:pole:mercedes "More than 10"
OK
# object encoding is ember string, now INCRBY, DECRBY won't work
object encoding races:pole:mercedes
"embstr"
# changing value to string