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开源软件名称:redis开源软件地址:https://gitee.com/mirrors/redis开源软件介绍:This README is just a fast quick start document. You can find more detailed documentation at redis.io. What is Redis?Redis is often referred to as a data structures server. What this means is that Redis provides access to mutable data structures via a set of commands, which are sent using a server-client model with TCP sockets and a simple protocol. So different processes can query and modify the same data structures in a shared way. Data structures implemented into Redis have a few special properties:
Another good example is to think of Redis as a more complex version of memcached, where the operations are not just SETs and GETs, but operations that work with complex data types like Lists, Sets, ordered data structures, and so forth. If you want to know more, this is a list of selected starting points:
Building RedisRedis can be compiled and used on Linux, OSX, OpenBSD, NetBSD, FreeBSD.We support big endian and little endian architectures, and both 32 bitand 64 bit systems. It may compile on Solaris derived systems (for instance SmartOS) but oursupport for this platform is best effort and Redis is not guaranteed towork as well as in Linux, OSX, and *BSD. It is as simple as: % make To build with TLS support, you'll need OpenSSL development libraries (e.g.libssl-dev on Debian/Ubuntu) and run: % make BUILD_TLS=yes To build with systemd support, you'll need systemd development libraries (suchas libsystemd-dev on Debian/Ubuntu or systemd-devel on CentOS) and run: % make USE_SYSTEMD=yes To append a suffix to Redis program names, use: % make PROG_SUFFIX="-alt" You can build a 32 bit Redis binary using: % make 32bit After building Redis, it is a good idea to test it using: % make test If TLS is built, running the tests with TLS enabled (you will need % ./utils/gen-test-certs.sh% ./runtest --tls Fixing build problems with dependencies or cached build optionsRedis has some dependencies which are included in the When you update the source code with make distclean This will clean: jemalloc, lua, hiredis, linenoise. Also if you force certain build options like 32bit target, no C compileroptimizations (for debugging purposes), and other similar build time options,those options are cached indefinitely until you issue a Fixing problems building 32 bit binariesIf after building Redis with a 32 bit target you need to rebuild itwith a 64 bit target, or the other way around, you need to perform a In case of build errors when trying to build a 32 bit binary of Redis, trythe following steps:
AllocatorSelecting a non-default memory allocator when building Redis is done by settingthe To force compiling against libc malloc, use: % make MALLOC=libc To compile against jemalloc on Mac OS X systems, use: % make MALLOC=jemalloc Monotonic clockBy default, Redis will build using the POSIX clock_gettime function as themonotonic clock source. On most modern systems, the internal processor clockcan be used to improve performance. Cautions can be found here:http://oliveryang.net/2015/09/pitfalls-of-TSC-usage/ To build with support for the processor's internal instruction clock, use: % make CFLAGS="-DUSE_PROCESSOR_CLOCK" Verbose buildRedis will build with a user-friendly colorized output by default.If you want to see a more verbose output, use the following: % make V=1 Running RedisTo run Redis with the default configuration, just type: % cd src% ./redis-server If you want to provide your redis.conf, you have to run it using an additionalparameter (the path of the configuration file): % cd src% ./redis-server /path/to/redis.conf It is possible to alter the Redis configuration by passing parameters directlyas options using the command line. Examples: % ./redis-server --port 9999 --replicaof 127.0.0.1 6379% ./redis-server /etc/redis/6379.conf --loglevel debug All the options in redis.conf are also supported as options using the commandline, with exactly the same name. Running Redis with TLS:Please consult the TLS.md file for more information onhow to use Redis with TLS. Playing with RedisYou can use redis-cli to play with Redis. Start a redis-server instance,then in another terminal try the following: % cd src% ./redis-cliredis> pingPONGredis> set foo barOKredis> get foo"bar"redis> incr mycounter(integer) 1redis> incr mycounter(integer) 2redis> You can find the list of all the available commands at https://redis.io/commands. Installing RedisIn order to install Redis binaries into /usr/local/bin, just use: % make install You can use Make install will just install binaries in your system, but will not configureinit scripts and configuration files in the appropriate place. This is notneeded if you just want to play a bit with Redis, but if you are installingit the proper way for a production system, we have a script that does thisfor Ubuntu and Debian systems: % cd utils% ./install_server.sh Note: The script will ask you a few questions and will setup everything you needto run Redis properly as a background daemon that will start again onsystem reboots. You'll be able to stop and start Redis using the script named Code contributionsNote: By contributing code to the Redis project in any form, including sendinga pull request via Github, a code fragment or patch via private email orpublic discussion groups, you agree to release your code under the termsof the BSD license that you can find in the COPYING file included in the Redissource distribution. Please see the CONTRIBUTING file in this source distribution for moreinformation. For security bugs and vulnerabilities, please see SECURITY.md. Redis internalsIf you are reading this README you are likely in front of a Github pageor you just untarred the Redis distribution tar ball. In both the casesyou are basically one step away from the source code, so here we explainthe Redis source code layout, what is in each file as a general idea, themost important functions and structures inside the Redis server and so forth.We keep all the discussion at a high level without digging into the detailssince this document would be huge otherwise and our code base changescontinuously, but a general idea should be a good starting point tounderstand more. Moreover most of the code is heavily commented and easyto follow. Source code layoutThe Redis root directory just contains this README, the Makefile whichcalls the real Makefile inside the Inside the root are the following important directories:
There are a few more directories but they are not very important for our goalshere. We'll focus mostly on Note: lately Redis was refactored quite a bit. Function names and filenames have been changed, so you may find that this documentation reflects the server.hThe simplest way to understand how a program works is to understand thedata structures it uses. So we'll start from the main header file ofRedis, which is All the server configuration and in general all the shared state isdefined in a global structure called
There are tons of other fields. Most fields are commented directly insidethe structure definition. Another important Redis data structure is the one defining a client.In the past it was called struct client { int fd; sds querybuf; int argc; robj **argv; redisDb *db; int flags; list *reply; // ... many other fields ... char buf[PROTO_REPLY_CHUNK_BYTES];} The client structure defines a connected client:
As you can see in the client structure above, arguments in a commandare described as typedef struct redisObject { unsigned type:4; unsigned encoding:4; unsigned lru:LRU_BITS; /* lru time (relative to server.lruclock) */ int refcount; void *ptr;} robj; Basically this structure can represent all the basic Redis data types likestrings, lists, sets, sorted sets and so forth. The interesting thing is thatit has a Redis objects are used extensively in the Redis internals, however in orderto avoid the overhead of indirect accesses, recently in many placeswe just use plain dynamic strings not wrapped inside a Redis object. server.cThis is the entry point of the Redis server, where the
There are two special functions called periodically by the event loop:
Inside server.c you can find code that handles other vital things of the Redis server:
commands.cThis file is auto generated by utils/generate-command-code.py, the content is based on the JSON files in the src/commands folder.These are meant to be the single source of truth about the Redis commands, and all the metadata about them.These JSON files are not meant to be used directly by anyone directly, instead that metadata can be obtained via the COMMAND command. networking.cThis file defines all the I/O functions with clients, masters and replicas(which in Redis are just special clients):
aof.c and rdb.cAs you can guess from the names, these files implement the RDB and AOFpersistence for Redis. Redis uses a persistence model based on the The implementation inside The db.cCertain Redis commands operate on specific data types; others are general.Examples of generic commands are Moreover The most important functions inside
The rest of the file implements the generic commands exposed to the client. object.cThe
This file also implements the replication.cThis is one of the most complex files inside Redis, it is recommended toapproach it only after getting a bit familiar with the rest of the code base.In this file there is the implementation of both the master and replica roleof Redis. One of the most important functions inside this file is This file also implements both the ScriptThe script unit is compose of 3 units
Other C files
Anatomy of a Redis commandAll the Redis commands are defined in the following way: void foobarCommand(client *c) { printf("%s",c->argv[1]->ptr); /* Do something with the argument. */ addReply(c,shared.ok); /* Reply something to the client. */} The command is then referenced inside {"foobar",foobarCommand,2,"rtF",0,NULL,0,0,0,0,0}, In the above example After the command operates in some way, it returns a reply to the client,usually using There are tons of command implementations inside the Redis source codethat can serve as examples of actual commands implementations. Writinga few toy commands can be a good exercise to get familiar with the code base. There are also many other files not described here, but it is useless tocover everything. We just want to help you with the first steps.Eventually you'll find your way inside the Redis code base :-) Enjoy! |
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