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How redis ensures hot data

Redis ensures the access efficiency and durability of hotspot data through the following technical measures: Data structure optimization: hash table and skip table Memory allocation optimization: memory sharding and object lazy deletion Persistence strategy: RDB snapshot and AOF log replication and sentinel: Replication and Sentinel Mechanisms

Apr 20, 2024 am 03:25 AM

redis并发访问数据丢失

How redis determines hot data

Redis uses slow query logs, memory sampling, modules and third-party tools to determine hot data. Once hotspot data is identified, steps can be taken to mitigate its impact, such as using caching, data sharding, and optimizing data structures.

Apr 20, 2024 am 03:09 AM

redis键值对

How to view data in redis

The method of viewing Redis data mainly depends on the data type: String type: GET, STRLEN List type: LRANGE, LINDEX, LLEN Hash type: HGET, HGETALL, HLEN Collection type: SMEMBERS, SCARD, SISMEMBER Ordered collection type: ZRANGE, ZRANGEBYSCORE, ZCARD general methods: TYPE, EXISTS, DEL

Apr 20, 2024 am 03:05 AM

redis键值对

How to change the password in redis

How to change the Redis password: Stop the Redis service. Create the password file redis.conf and add requirepass new_password. Save and start the Redis service. Use -a new_password to connect to Redis to verify the password.

Apr 20, 2024 am 03:00 AM

redis密码重置

How to start redis server

Starting the Redis server requires the following steps: 1. Download and install Redis. 2. Open a terminal, navigate to the installation directory and run the "redis-server" command. 3. Check the server running status and run the "redis-cli ping" command. 4. (Optional) Configure startup parameters such as port, daemon mode, and maximum number of connections. 5. Stop the server and run the "redis-cli shutdown" command.

Apr 20, 2024 am 02:51 AM

redis

How to implement current limiting in redis

Redis implements current limiting and uses the token bucket algorithm and sliding window algorithm. The token bucket algorithm limits incoming requests, and the sliding window algorithm records the number of requests within a certain period of time and determines whether it exceeds the threshold. Redis uses the incr/decr command to operate the token bucket, and uses the time and incrby commands to record the number of sliding window requests. Current limiting configuration is implemented through the set and config set commands. The sample code sets the token bucket capacity and rate, sliding window size and threshold, and checks whether the request is current limited.

Apr 20, 2024 am 02:39 AM

redis

How to solve redis read-write lock

Redis does not support the native read-write lock mechanism. Solutions include: third-party tools: RedLock or RwLock; custom solutions: token-based: using read_lock and write_lock keys; condition variable-based: using a lock key with a random number.

Apr 20, 2024 am 01:15 AM

redis

How redis gets data

Redis provides the following ways to obtain data: GET: Get the value of the specified key. MGET: Get the values of multiple keys at the same time. HGET: Get the value of the specified field in the hash table. HGETALL: Get the values of all fields in the hash table. LINDEX: Gets the element at the specified index in the list. LRANGE: Get the elements in the specified range in the list.

Apr 20, 2024 am 01:12 AM

redis

How to get all keys in redis

Method to get all keys in Redis: KEYS command: Get all key names matching the specified pattern. SCAN command: iteratively obtain all key names. DUMP combined with the EVAL command: export the values of all keys and get the key names. Using the Redis client library: Use the keys() method provided by the corresponding library to obtain the key name.

Apr 20, 2024 am 01:09 AM

pythonredis

How to get data in redis

Common ways to obtain data in Redis are: GET: directly obtain the value of the specified key. MGET: Get the values of multiple keys at the same time and return a list. HGET: Get the value of the specified field in the hash table. HMGET: Get the values of multiple fields in the hash table and return a list. LRANGE: Get the elements in the specified range in the list. ZRANGE: Gets elements within a specified range in an ordered collection. ZREVRANGE: Get the elements in the specified range in the ordered set, sorted from large to small.

Apr 20, 2024 am 01:03 AM

redis

How does redis ensure consistency with the database

To ensure data consistency between Redis and the database, the following methods can be used: Transactional updates: Encapsulate Redis and database updates into atomic transactions to avoid inconsistencies. Optimistic locking: monitor the key to be updated and check whether the key has been modified before updating to avoid concurrency conflicts. Publish-Subscribe: Use a Redis channel to publish messages, and subscribers update data to maintain consistency. Data replication: Replicate data between Redis instances through master-slave replication or sentinel mechanism to ensure data consistency. Batch update: Batch a large number of updates to reduce the number of communications and improve performance and consistency.

Apr 20, 2024 am 01:00 AM

redis

How to ensure consistency between redis and mysql

Methods to ensure consistency between Redis and MySQL include direct writing to MySQL and transaction compensation mechanism: direct writing to MySQL: synchronizing MySQL data changes to Redis through triggers, ensuring consistency but lower performance; transaction compensation mechanism: writing to Redis first , while recording compensation transactions, tolerating short-term unavailability, but with slightly lower consistency and higher system complexity.

Apr 20, 2024 am 12:57 AM

mysqlredis

How to solve the inconsistency between redis cache and database double write

To solve the double-write inconsistency problem between the Redis cache and the database, the following methods can be used: Use queues: Put the data update request into the queue, ensuring that it is written to the database first and then the cache is updated. Use optimistic locking: Check whether the data has been modified when updating. If it has been modified, cancel the update and notify to try again. Use event mechanism: When the database is updated, an event is triggered to notify the application to update the cache, and the application needs to listen to the database update event. Use pessimistic locking: Lock related records before writing to the database to prevent other processes from updating the same record at the same time. Use eventual consistency: Allow the cache and database to be temporarily inconsistent and rely on the application's eventual consistency mechanism to ensure eventual consistency.

Apr 20, 2024 am 12:54 AM

redis

How to solve redis cache breakdown

Methods to solve Redis cache breakdown: Use distributed locks to prevent concurrent cache queries, allowing lock-holding requests to obtain data and update the cache; limit current to reduce database pressure and prevent too many concurrent queries; cache null values to prevent direct access to the database , and force retry later; preload hotspot data in advance to ensure availability; start asynchronous tasks to load data asynchronously to avoid simultaneous database access.

Apr 20, 2024 am 12:49 AM

redis异步加载并发请求