Compare Redis, Memcache, MongoDB from the following dimensions

1. Performance

are relatively high, performance is not a bottleneck for us

In general, the TPS is about the same as Redis and Memcache, more than MongoDB

2, the convenience of the operation

Memcache Data Structure Single

Redis is rich, data manipulation, Redis better, less network IO times

MongoDB supports rich data expression, index, most similar relational database, support query language is very rich

3. Size of memory space and amount of data

Redis has added its own VM features after the 2.0 release, breaking the limits of physical memory; You can set the expiration time for key value (similar to memcache)

Memcache can modify the maximum available memory, using the LRU algorithm

MongoDB is suitable for large data storage, depends on operating system VM to do memory management, eat memory is also very bad, service not with other services together

4. Availability (single point of issue)

For a single point of problem,

Redis, which relies on clients for distributed reads and writes, and master-slave replication relies on the entire snapshot every time the primary node is reconnected from the node, without incremental replication, due to performance and efficiency issues,

Therefore, the single point problem is more complicated, the automatic sharding is not supported, and the dependent program is required to set the consistent hash mechanism.

An alternative is to use your own proactive replication (multiple storage) instead of Redis's own replication mechanism, or change to incremental replication (you need to implement it yourself), consistency issues and performance tradeoffs

Memcache itself has no data redundancy mechanism, it is not necessary, for fault prevention, relying on mature hash or ring algorithm to solve the single point of failure caused by the jitter problem.

MongoDB supports Master-slave,replicaset (internal using Paxos election algorithm, automatic fault recovery), auto sharding mechanism, blocking the failover and segmentation mechanism to the client.

5. Reliability (persistent)

For data persistence and data recovery,

Redis Support (snapshot, AOF): dependent on snapshots for persistence, AOF enhances reliability while impacting performance

Memcache not supported, usually used in cache, improve performance;

MongoDB supports persistent reliability from the 1.8 release with the binlog approach

6. Data consistency (transactional support)

Memcache in concurrent scenarios, with CAS to ensure consistency

Redis transaction support is weak and can only guarantee continuous execution of each operation in a transaction

MongoDB does not support transactions

7. Data analysis

MongoDB has built-in data analysis capabilities (MapReduce), others do not support

8. Application Scenario

Redis: More performance operations and calculations with smaller data volumes

Memcache: Used to reduce database load in dynamic system, improve performance, cache, improve performance (suitable for read and write less, for a large amount of data, you can use sharding)

MongoDB: The main solution to the massive data access efficiency problem

Compare Redis, Memcache, MongoDB from the following dimensions