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This article mainly introduces Redis how to use pipeline, the article is very detailed, has a certain reference value, interested friends must read it!

Use pipeline

Redis is a TCP server based on the request-response model. It means a single request RTT (round trip time), depending on the current network condition. This can cause a single Redis request to be very fast, such as through a local loop network card. It can be very slow, such as in an environment with poor network conditions.

On the other hand, every request-response of Redis involves read and write system calls. It may even trigger multiple epoll_wait system calls (Linux platform). This causes Redis to keep switching between user mode and kernel mode.

Static int connSocketRead (connection * conn, void * buf, size_t buf_len) {/ / read system call int ret = read (conn- > fd, buf, buf_len);} static int connSocketWrite (connection * conn, const void * data, size_t data_len) {/ / write system call int ret = write (conn- > fd, data, data_len) } int aeProcessEvents (aeEventLoop * eventLoop, int flags) {/ / event triggered, numevents = aeApiPoll (eventLoop, tvp) for epoll_wait system call under Linux;}

So, how to save round-trip time and system calls? Batch processing is a good way.

To this end, Redis provides "pipeline". The principle of pipeline is simple: multiple commands are packaged and sent as "one command". After the Redis is received, it is parsed into multiple commands to execute. Finally, multiple results are packaged and returned.

Pipeline can effectively improve the performance of Redis.

However, there are a few things you need to pay attention to when using pipeline

Pipeline cannot guarantee atomicity. During one pipeline command execution, other client-initiated commands may be executed. Keep in mind that pipeline is just batch processing commands. To ensure atomicity, use MULTI or Lua scripts.

Do not have too many pipeline commands at a time. When using pipeline, Redis temporarily stores the response result of the pipeline command in memory Reply buffer and waits for the execution of all commands to return. If there are too many pipeline commands, it may result in more memory consumption. You can split a single pipeline into multiple pipeline.

The above is all the content of the article "how Redis uses pipeline". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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