RDBMS, memcache, rdbmsmemcache

RDBMS, memcache, rdbmsmemcache

1. RDBMS (Relational Database Management System) is a System that organizes data into related rows and columns, the computer software used to manage relational databases is the relational database management system. Common Database software includes Oracle and SQL Server.

2. memcache is a distributed high-speed cache system developed by Brad Fitzpatrick of LiveJournal. However, it is currently used by many websites to speed up Website access, especially for some large websites that require frequent access to databases, the speed of access is significantly improved. This is an open-source software, which is released with BSD license authorization.
The workflow of MemCache is as follows: first check whether the client's request data is in memcached. If yes, directly return the request data without any operations on the database; if the requested data is not in memcached, check the database, return the data obtained from the database to the client, and cache the data to memcached, must be explicitly implemented by the Program). Data in memcached is updated at the same time each time the database is updated to ensure consistency. When the memory space allocated to memcached is Used up, LRU (Least Recently Used, Least Recently Used) is Used) when a policy is added with an expiration Policy, the invalid data is replaced first, and then the data that has not been used recently is replaced.
Memcache is a high-performance distributed memory object cache system. By maintaining a unified and huge hash table in the memory, Memcache can be used to store data in various formats, including image, video, file, and database retrieval results. Simply put, the data is called to the memory and then read from the memory, which greatly improves the reading speed. --- The above content comes from Baidu

3. Share the following articleEvolution of large-scale website architecture (I)

: Http://blog.jobbole.com/87736/ (also from this article)
See the figure below to help you understand the MemCache application (website ):