Common APIs for Redis data types and usage scenarios

I. GENERAL Command

1. Keys traverses all keys

Generally not used in production environments

2, the total number of Dbsize key

3. Exists key

4. del key Delete specified key-value

5, expire key secods set how many seconds expired

How many seconds of TTL are left to expire

Persist Cancel Expiration Time

6. Type Return key

Second, single thread

Only one command can be executed at a time

Reject long slow commands (keys, etc.)

Why is a single thread so fast?

1, pure memory (main)

2. Non-blocking IO

3. Avoid thread switching and race consumption

Third, the data type

1. String

Type: Can save string, Integer, binary, JSON, etc.

Size: Can save 512M

Scenario: Cache, counter

Command:

1.1, get, set, Del

1.2. Set K v whether or not K exists, all sets

Setnx K v K does not exist before setting

Set K v xx k exists only setting

1.3. mset Batch Setup

Mget Bulk Acquisition

1.5

Getset key NewValue sets a new key and returns the old value

Append key value appends value to the old value

Strlen Key returns the length of the string (note Chinese)

1.6

Incrbyfloat increasing floating-point numbers

GetRange get string to make all values subscript

SetRange sets the value of the specified subscript

1.7, suitable for doing counter, single process without competition

INCR self-increment 1 if key does not exist for 1

DECR minus 1 If key does not exist as-1

Incrby self-increment k, if key does not exist for K

Decrby-minus key if key does not exist as-K

Usage Scenarios: Caching apps

2. Hash

A key that corresponds to the structure of multiple key values can be understood as a small redis

The hash API operation starts with H

2.1, Hset, Hget, Hdel

2.2

Hexists Key Exists field

Total number of field in Hlen key

2.3

Hmget Bulk Acquisition

Hmser Batch Setup

2.4

Hgetall

2.5, Hsetnx, Hincrby, hincrbyfloat

Usage Scenarios

Count the number of visits per user's personal page

Hincrby User:1:info PageView Count

Cache Storage Video Basic information

Programming Comparison:

First: Serialize the whole data into a string

The second type: Store data in a string, respectively

The third type: depositing data into a hash

4. List

Orderly, repeatable, left and right sides can be inserted pop-up

The list API starts with L

4.1, increase

Rpush Insert from right

Lpush Insert from left

Linsert key Before|after value newvalue inserting data before and after the specified value

4.2. By deleting

Lpop Popup from left

Rpop from right.

Lrem Key count value removes all values equal to Balue from the list, based on the count values

4.3. Check

Lrange

Lindex

Llen

4.4, change

LSet

4.5. Leak-Checking and vacancy

Blpop

Brpop

4.6. Usage Scenarios

Weibo timeline

4.7. TIPS

1, Stack

2. Queue

3, a fixed number of lists

5. Collection

Cannot repeat, unordered, and support inter-collection operations within a collection

5.1. Inside the Set

Usage Scenarios

Can be used in the likes, the lottery.

5.2. Inter-Collection

Usage scenarios:

Common concern, common fans

6. Ordered set

Characteristics:

Api

6.1. Zadd add Element

6.2. Zrem Delete Element

6.3, Zscore get the score

6.4. Zincrby increase or decrease the score

6.5, Zcard returns the total number of elements

Instance:

6.6. Zrange returns the ascending element in the specified index range

6.7. Zrangebyscore returns the ascending element that formulates the fractional range

6.8, Zermrangebyrank

6.9, Zremrangbyscore Delete the ascending element of the specified fraction

Usage Scenarios: Leaderboards

Common APIs for Redis data types and usage scenarios