redis / redis-doc

Redis documentation source code for markdown and metadata files, conversion scripts, and so forth

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:

• Redis cares to store them on disk, even if they are always served and modified into the server memory. This means that Redis is fast, but that it is also non-volatile.
• The implementation of data structures emphasizes memory efficiency, so data structures inside Redis will likely use less memory compared to the same data structure modelled using a high-level programming language.
• Redis offers a number of features that are natural to find in a database, like replication, tunable levels of durability, clustering, and high availability.

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:

• Introduction to Redis data types. https://redis.io/topics/data-types-intro
• Try Redis directly inside your browser. https://try.redis.io
• The full list of Redis commands. https://redis.io/commands
• There is much more inside the official Redis documentation. https://redis.io/documentation

Building Redis

Redis can be compiled and used on Linux, OSX, OpenBSD, NetBSD, FreeBSD. We support big endian and little endian architectures, and both 32 bit and 64 bit systems.

It may compile on Solaris derived systems (for instance SmartOS) but our support for this platform is best effort and Redis is not guaranteed to work 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 (such as 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 tcl-tls installed):

% ./utils/gen-test-certs.sh
% ./runtest --tls

Fixing build problems with dependencies or cached build options

Redis has some dependencies which are included in the deps directory. make does not automatically rebuild dependencies even if something in the source code of dependencies changes.

When you update the source code with git pull or when code inside the dependencies tree is modified in any other way, make sure to use the following command in order to really clean everything and rebuild from scratch:

% make distclean

This will clean: jemalloc, lua, hiredis, linenoise and other dependencies.

Also if you force certain build options like 32bit target, no C compiler optimizations (for debugging purposes), and other similar build time options, those options are cached indefinitely until you issue a make distclean command.

Fixing problems building 32 bit binaries

If after building Redis with a 32 bit target you need to rebuild it with a 64 bit target, or the other way around, you need to perform a make distclean in the root directory of the Redis distribution.

In case of build errors when trying to build a 32 bit binary of Redis, try the following steps:

• Install the package libc6-dev-i386 (also try g++-multilib).
• Try using the following command line instead of make 32bit: make CFLAGS="-m32 -march=native" LDFLAGS="-m32"

Allocator

Selecting a non-default memory allocator when building Redis is done by setting the MALLOC environment variable. Redis is compiled and linked against libc malloc by default, with the exception of jemalloc being the default on Linux systems. This default was picked because jemalloc has proven to have fewer fragmentation problems than libc malloc.

To force compiling against libc malloc, use:

% make MALLOC=libc

To compile against jemalloc on Mac OS X systems, use:

% make MALLOC=jemalloc

Monotonic clock

By default, Redis will build using the POSIX clock_gettime function as the monotonic clock source. On most modern systems, the internal processor clock can 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 build

Redis 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 Redis

To 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 additional parameter (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 directly as 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 command line, with exactly the same name.

Running Redis with TLS:

Please consult the TLS.md file for more information on how to use Redis with TLS.

Playing with Redis

You can use redis-cli to play with Redis. Start a redis-server instance, then in another terminal try the following:

% cd src
% ./redis-cli
redis> ping
PONG
redis> set foo bar
OK
redis> get foo
"bar"
redis> incr mycounter
(integer) 1
redis> incr mycounter
(integer) 2
redis>

You can find the list of all the available commands at https://redis.io/commands.

Installing Redis

In order to install Redis binaries into /usr/local/bin, just use:

% make install

You can use make PREFIX=/some/other/directory install if you wish to use a different destination.

make install will just install binaries in your system, but will not configure init scripts and configuration files in the appropriate place. This is not needed if you just want to play a bit with Redis, but if you are installing it the proper way for a production system, we have a script that does this for Ubuntu and Debian systems:

% cd utils
% ./install_server.sh

Note: install_server.sh will not work on Mac OSX; it is built for Linux only.

The script will ask you a few questions and will setup everything you need to run Redis properly as a background daemon that will start again on system reboots.

You'll be able to stop and start Redis using the script named /etc/init.d/redis_<portnumber>, for instance /etc/init.d/redis_6379.

Code contributions

By contributing code to the Redis project in any form, including sending a pull request via GitHub, a code fragment or patch via private email or public discussion groups, you agree to release your code under the terms of the Redis Software Grant and Contributor License Agreement. Redis software contains contributions to the original Redis core project, which are owned by their contributors and licensed under the 3BSD license. Any copy of that license in this repository applies only to those contributions. Redis releases all Redis project versions from 7.4.x and thereafter under the RSALv2/SSPL dual-license as described in the LICENSE.txt file included in the Redis source distribution.

Please see the CONTRIBUTING.md file in this source distribution for more information. For security bugs and vulnerabilities, please see SECURITY.md.

Redis Trademarks

The purpose of a trademark is to identify the goods and services of a person or company without causing confusion. As the registered owner of its name and logo, Redis accepts certain limited uses of its trademarks but it has requirements that must be followed as described in its Trademark Guidelines available at: https://redis.com/legal/trademark-guidelines/.

Redis internals

If you are reading this README you are likely in front of a Github page or you just untarred the Redis distribution tar ball. In both the cases you are basically one step away from the source code, so here we explain the Redis source code layout, what is in each file as a general idea, the most important functions and structures inside the Redis server and so forth. We keep all the discussion at a high level without digging into the details since this document would be huge otherwise and our code base changes continuously, but a general idea should be a good starting point to understand more. Moreover most of the code is heavily commented and easy to follow.

Source code layout

The Redis root directory just contains this README, the Makefile which calls the real Makefile inside the src directory and an example configuration for Redis and Sentinel. You can find a few shell scripts that are used in order to execute the Redis, Redis Cluster and Redis Sentinel unit tests, which are implemented inside the tests directory.

Inside the root are the following important directories:

• src: contains the Redis implementation, written in C.
• tests: contains the unit tests, implemented in Tcl.
• deps: contains libraries Redis uses. Everything needed to compile Redis is inside this directory; your system just needs to provide libc, a POSIX compatible interface and a C compiler. Notably deps contains a copy of jemalloc, which is the default allocator of Redis under Linux. Note that under deps there are also things which started with the Redis project, but for which the main repository is not redis/redis.

There are a few more directories but they are not very important for our goals here. We'll focus mostly on src, where the Redis implementation is contained, exploring what there is inside each file. The order in which files are exposed is the logical one to follow in order to disclose different layers of complexity incrementally.

Note: lately Redis was refactored quite a bit. Function names and file names have been changed, so you may find that this documentation reflects the unstable branch more closely. For instance, in Redis 3.0 the server.c and server.h files were named redis.c and redis.h. However the overall structure is the same. Keep in mind that all the new developments and pull requests should be performed against the unstable branch.

server.h

The simplest way to understand how a program works is to understand the data structures it uses. So we'll start from the main header file of Redis, which is server.h.

All the server configuration and in general all the shared state is defined in a global structure called server, of type struct redisServer. A few important fields in this structure are:

• server.db is an array of Redis databases, where data is stored.
• server.commands is the command table.
• server.clients is a linked list of clients connected to the server.
• server.master is a special client, the master, if the instance is a replica.

There are tons of other fields. Most fields are commented directly inside the structure definition.

Another important Redis data structure is the one defining a client. In the past it was called redisClient, now just client. The structure has many fields, here we'll just show the main ones:

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:

• The fd field is the client socket file descriptor.
• argc and argv are populated with the command the client is executing, so that functions implementing a given Redis command can read the arguments.
• querybuf accumulates the requests from the client, which are parsed by the Redis server according to the Redis protocol and executed by calling the implementations of the commands the client is executing.
• reply and buf are dynamic and static buffers that accumulate the replies the server sends to the client. These buffers are incrementally written to the socket as soon as the file descriptor is writable.

As you can see in the client structure above, arguments in a command are described as robj structures. The following is the full robj structure, which defines a Redis object:

struct redisObject {
    unsigned type:4;
    unsigned encoding:4;
    unsigned lru:LRU_BITS; /* LRU time (relative to global lru_clock) or
                            * LFU data (least significant 8 bits frequency
                            * and most significant 16 bits access time). */
    int refcount;
    void *ptr;
};

Basically this structure can represent all the basic Redis data types like strings, lists, sets, sorted sets and so forth. The interesting thing is that it has a type field, so that it is possible to know what type a given object has, and a refcount, so that the same object can be referenced in multiple places without allocating it multiple times. Finally the ptr field points to the actual representation of the object, which might vary even for the same type, depending on the encoding used.

Redis objects are used extensively in the Redis internals, however in order to avoid the overhead of indirect accesses, recently in many places we just use plain dynamic strings not wrapped inside a Redis object.

server.c

This is the entry point of the Redis server, where the main() function is defined. The following are the most important steps in order to startup the Redis server.

• initServerConfig() sets up the default values of the server structure.
• initServer() allocates the data structures needed to operate, setup the listening socket, and so forth.
• aeMain() starts the event loop which listens for new connections.

There are two special functions called periodically by the event loop:

1. serverCron() is called periodically (according to server.hz frequency), and performs tasks that must be performed from time to time, like checking for timed out clients.
2. beforeSleep() is called every time the event loop fired, Redis served a few requests, and is returning back into the event loop.

Inside server.c you can find code that handles other vital things of the Redis server:

• call() is used in order to call a given command in the context of a given client.
• activeExpireCycle() handles eviction of keys with a time to live set via the EXPIRE command.
• performEvictions() is called when a new write command should be performed but Redis is out of memory according to the maxmemory directive.
• The global variable redisCommandTable defines all the Redis commands, specifying the name of the command, the function implementing the command, the number of arguments required, and other properties of each command.

commands.c

This 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 by anyone directly, instead that metadata can be obtained via the COMMAND command.

networking.c

This file defines all the I/O functions with clients, masters and replicas (which in Redis are just special clients):

• createClient() allocates and initializes a new client.
• The addReply*() family of functions are used by command implementations in order to append data to the client structure, that will be transmitted to the client as a reply for a given command executed.
• writeToClient() transmits the data pending in the output buffers to the client and is called by the writable event handler sendReplyToClient().
• readQueryFromClient() is the readable event handler and accumulates data read from the client into the query buffer.
• processInputBuffer() is the entry point in order to parse the client query buffer according to the Redis protocol. Once commands are ready to be processed, it calls processCommand() which is defined inside server.c in order to actually execute the command.
• freeClient() deallocates, disconnects and removes a client.

aof.c and rdb.c

As you can guess from the names, these files implement the RDB and AOF persistence for Redis. Redis uses a persistence model based on the fork() system call in order to create a process with the same (shared) memory content of the main Redis process. This secondary process dumps the content of the memory on disk. This is used by rdb.c to create the snapshots on disk and by aof.c in order to perform the AOF rewrite when the append only file gets too big.

The implementation inside aof.c has additional functions in order to implement an API that allows commands to append new commands into the AOF file as clients execute them.

The call() function defined inside server.c is responsible for calling the functions that in turn will write the commands into the AOF.

db.c

Certain Redis commands operate on specific data types; others are general. Examples of generic commands are DEL and EXPIRE. They operate on keys and not on their values specifically. All those generic commands are defined inside db.c.

Moreover db.c implements an API in order to perform certain operations on the Redis dataset without directly accessing the internal data structures.

The most important functions inside db.c which are used in many command implementations are the following:

• lookupKeyRead() and lookupKeyWrite() are used in order to get a pointer to the value associated to a given key, or NULL if the key does not exist.
• dbAdd() and its higher level counterpart setKey() create a new key in a Redis database.
• dbDelete() removes a key and its associated value.
• emptyData() removes an entire single database or all the databases defined.

The rest of the file implements the generic commands exposed to the client.

object.c

The robj structure defining Redis objects was already described. Inside object.c there are all the functions that operate with Redis objects at a basic level, like functions to allocate new objects, handle the reference counting and so forth. Notable functions inside this file:

• incrRefCount() and decrRefCount() are used in order to increment or decrement an object reference count. When it drops to 0 the object is finally freed.
• createObject() allocates a new object. There are also specialized functions to allocate string objects having a specific content, like createStringObjectFromLongLong() and similar functions.

This file also implements the OBJECT command.

replication.c

This is one of the most complex files inside Redis, it is recommended to approach 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 role of Redis.

One of the most important functions inside this file is replicationFeedSlaves() that writes commands to the clients representing replica instances connected to our master, so that the replicas can get the writes performed by the clients: this way their data set will remain synchronized with the one in the master.

This file also implements both the SYNC and PSYNC commands that are used in order to perform the first synchronization between masters and replicas, or to continue the replication after a disconnection.

Script

The script unit is composed of 3 units:

• script.c - integration of scripts with Redis (commands execution, set replication/resp, ...)
• script_lua.c - responsible to execute Lua code, uses script.c to interact with Redis from within the Lua code.
• function_lua.c - contains the Lua engine implementation, uses script_lua.c to execute the Lua code.
• functions.c - contains Redis Functions implementation (FUNCTION command), uses functions_lua.c if the function it wants to invoke needs the Lua engine.
• eval.c - contains the eval implementation using script_lua.c to invoke the Lua code.

Other C files

• t_hash.c, t_list.c, t_set.c, t_string.c, t_zset.c and t_stream.c contains the implementation of the Redis data types. They implement both an API to access a given data type, and the client command implementations for these data types.
• ae.c implements the Redis event loop, it's a self contained library which is simple to read and understand.
• sds.c is the Redis string library, check https://github.com/antirez/sds for more information.
• anet.c is a library to use POSIX networking in a simpler way compared to the raw interface exposed by the kernel.
• dict.c is an implementation of a non-blocking hash table which rehashes incrementally.
• cluster.c implements the Redis Cluster. Probably a good read only after being very familiar with the rest of the Redis code base. If you want to read cluster.c make sure to read the Redis Cluster specification.

Anatomy of a Redis command

All 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 function is referenced by a JSON file, together with its metadata, see commands.c described above for details. The command flags are documented in the comment above the struct redisCommand in server.h. For other details, please refer to the COMMAND command. https://redis.io/commands/command/

After the command operates in some way, it returns a reply to the client, usually using addReply() or a similar function defined inside networking.c.

There are tons of command implementations inside the Redis source code that can serve as examples of actual commands implementations (e.g. pingCommand). Writing a 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 to cover everything. We just want to help you with the first steps. Eventually you'll find your way inside the Redis code base :-)

Enjoy!

redis-doc's Issues

Add clarity to "partial synchronization"

We now had several users in IRC asking why Partial resynchronization failed with "Partial resynchronization not possible (no cached master)" when the slave was restarted.

The section in the documentation could be improved: https://github.com/antirez/redis-doc/blob/master/topics/replication.md#partial-resynchronization

I will add one or two sentences later (I don't have the time right now)

Clarify: SCAN commands vs Redis Cluster

I would assume that the two are not compatible, but a clarification would be helpful.

Command Does Not Include Response Type

commands.json should include an expected response type for each command. For example, INCR should have a response property of "integer", because under normal operating conditions it responds with a long integer.

ZREVRANGEBYLEX not in documentation

While writing an automated processor which combines information from the redis C table with the documentation, it noticed that zrevrangebylex is in the command table but not in the commands.json file:

https://github.com/antirez/redis/blob/78a012d81a0f487b92b2b79a91de1f28697100e8/src/redis.c#L185

Just thought I'd let you know. :-)

I'm assuming its performance profile is the same as ZRANGEBYLEX:

"O(log(N)+M) with N being the number of elements in the sorted set and M the number of elements being returned. If M is constant (e.g. always asking for the first 10 elements with LIMIT), you can consider it O(log(N))."

I mention that one in particular because it is user facing and I'd say it's fairly certain it should be documented. Though here's the others that don't have documentation, and some may be omitted on purpose:

• latency
• pfdebug
• pfselftest
• psync
• replconf
• restore-asking
• readonly
• readwrite

Bad link in /topics/data-types-intro

There is a link to /topics/commands/decr on that page (should go to /commands/decr) caused by a missing forward slash in the anchor tag.

Arguments for [P]SUBSCRIBE commands are apparently not correctly documented

[P]SUBSCRIBE take a list of channels. Documentation (commands.json) specify only a single channel.

wooga uses redis

hi,

we use redis as backend datastore for two facebook games: "Happy Hospital" and "Monster World".

cheers
tim

http://www.wooga.com/games/

Command Reference pages need reorganizing

Each command reference page starts with the Time Complexity header. Then it has the time complexity information. Then in the same section with no header is a description of what the command does.

That order hides the most important information which is what the command does.

A good solution would be to move the description above the Time Complexity header.

In addition the Availability information would be better as a section and put somewhere after what the command does.

Fotolog uses redis

Fotolog, a photo-sharing social network with over 30 million members, has recently begun using redis extensively. Because of this, we actually wrote our own redis client in scala as well, using the netty framework. It's an extremely lightweight, high-performance client that scales very well but, at the same time, takes care of a lot of the work for you, such as type conversions, clustering, etc... It also features binary safe values, asynchronous calls, protocol pipelining and connection multiplexing.

https://github.com/andreyk0/redis-client-scala-netty

sharpcloud uses redis

Hey, just wanted to let you know that we're (sharpcloud) using redis as our caching layer. What's interesting is we're actually on Windows Azure so are using a windows build of redis which I'm happy to say is working very nicely. Happy for you to use our logo if you'd like which you can grab here https://directory.sharpcloud.com/staticimages/logo_on_black.png.

Keep up the good work.
Andy
http://www.sharpcloud.com

Minor correction to "transactions" docs

In the "Usage" section of http://redis.io/topics/transactions, the statement reads:

As it is possible to see from the session above, MULTI returns an array of replies, where every element is the reply of a single command in the transaction, in the same order the commands were issued.

I'm pretty sure this statement means "...EXEC returns an array of replies...", because EXEC does return an array of replies, whereas MULTI always returns "OK", even as that is stated in the same page, just above:

A Redis transaction is entered using the MULTI command. The command always replies with OK.

twitter-clone out of date

This document is out of date. Should be re-written to reflect current data types, including Hashes

https://github.com/antirez/redis-doc/blob/master/topics/twitter-clone.md

Redis common patterns section

Hi,

I use a lot Redis and I think that it's for DBs what RISC it's of CPUs. A set of simple functions that you can use to build your own, to extend it and have a database that matches your needs.

So using redis I noticed common patterns like implementing message queues using an array with blocking pop and a "working" set. Or using a sorted set to implement a scheduler using timestamp as score.

What do you think about adding on documentation/website a section with these patterns? I think that can be useful for people to understand better how to use redis or to extend them avoiding common mistakes.

TweetDeck uses Redis

Hi, just wanted to let you know that TweetDeck uses Redis internally for analytics, and to store certain bits of synced data.

Fee free to use our logo - I can provide specific sizes, if required.

Untitled

Document DEBUG SLEEP command

Found it in the source. Should probably be in the docs too.

Locating/Formatting SENTINEL commands

I'm willing to write the docs on the SENTINEL commands, but want to make sure I have the correct place to put them.

I'll be adding some text to the topics/sentinel.md file to document the undocumented commands. I can also write the commands/sentinel.md file to document the command, but am unsure about where additional text should go. For example, SENTINEL is a command which only works if the server is invoked with sentinel mode. Does it need it's own section or just an entry in commands.json which looks like the rest? It is this latter question which is forefront of my mind on this at the moment.

Command group bar on redis.io

Not sure if it is a right issue tracker for this, but anyway:

http://redis.io/commands has a nice command group bar (All, Keys, Strings...).

But this bar is not shown on the command info page.

For example, here: http://redis.io/commands/del

Please do show the bar on each page of http://redis.io/commands/, or otherwise it takes too many clicks to go from one command group to another.

Document commands that can't be run in a script

The following commands can't be run inside a script

• brpop
• blpop
• brpoplpush
• spop
• auth
• save
• multi
• exec
• discard
• sync
• psync
• replconf
• slaveof
• unsubscribe
• psubscribe
• punsubscribe
• watch
• unwatch
• eval
• evalsha
• script

pennyace.com is using redis...

...and it is awesome! The realtime component of pennyace.com fits nicely with Redis. It seriously just works. Not sure we could have launched without it. Cheers!

Document SENTINEL sentinels <name> command

Moving this here from the command request on Redis' issue list. I'll be adding this in the next several days, but want to have it here to track it and refer to it in a pull request.

PoraOra is using Redis

PoraOra (educational 3D world for children) http://poraora.com/ is using Redis.

doc tweak /ad/as/ ... sorry about the trivial...

http://redis.io/topics/partitioning
Under:
Data store or cache?

"Partitioning when using Redis ad a data store or cache is conceptually the same, however there is a huge difference."

ad->as

nk.pl is uses redis

Hi!

Nasza Klasa (http://nk.pl) - the largest social network in Poland - uses Redis as a cache and database. Currently we have more than 500 Redis instances.

Add iRedis to PHP client list

Hello, I have written and released a Fork of Redisent called iRedis. It encapsulates everything a little better I think. It is also sill PHP 5.1+ compatible, whereas the new Redisent is now PHP 5.3 only.

The repository is here: https://github.com/ivorychicken/iRedis

Thanks,
Dan

C# ServiceStack.Redis is non-free

Can somebody please edit clients list to mention ServiceStack.Redis is open source but requires license to use. Should this library be recommended?

Io client library url invalid

The iodis client library's url is invalid, see: https://github.com/ichverstehe/iodis
Apparently the author moved to another account: https://github.com/vangberg/
The new url for the Io library is: https://github.com/vangberg/iodis

Please add our scala client to http://redis.io/clients

We at Fotolog wrote our own redis client in scala using the netty framework. It's an extremely lightweight, high-performance client that scales very well but, at the same time, takes care of a lot of the work for you, such as type conversions, clustering, etc... It also features binary safe values, asynchronous calls, protocol pipelining and connection multiplexing.

https://github.com/andreyk0/redis-client-scala-netty

List more topics

I'd like http://redis.io/documentation to link to the "introduction" and "transactions" pages. They're accessible from elsewhere, but a comprehensive index would make them harder for new users to miss.

Also, the introduction contains a broken link to /topics/cache.

We use Redis (Moodstocks)

I have followed the "let us know" link at http://www.redis.io/topics/whos-using-redis. I just wanted to tell you that we use Redis (through Ohm) as our main datastore in our applications Moodstocks Notes and Moodstocks Contacts, and to store some data (mainly statistics and credentials) in Moodstocks API.

References:
http://www.moodstocks.com/discover-our-products/
http://www.moodstocks.com/2010/11/26/the-tech-behind-moodstocks-notes/
http://www.moodstocks.com/2010/12/20/the-tech-behind-moodstocks-api/
http://mashable.com/2010/12/18/moodstocks/
http://techcrunch.com/2010/12/10/moodstocks-notes-is-stickybits-without-the-barcodes/

Feel free to add us to the users page if you like :)

Engage uses Redis

Engage uses Redis for session keys and stats. Works like a bomb! Thanks guys
http://engage.calibreapps.com/

EXPIRE on existing key does not work as described

http://www.redis.io/topics/expire

"Trying to call EXPIRE against a key that already has an associated timeout will not change the timeout of the key, but will just return 0."

Unfortunately, it turns out that this statement is incorrect--EXPIRE on an existing key replaces the prior TTL with the TTL argument from the EXPIRE command.

Redis 2.4.8:

redis db2:6381[2]> setex test 20 asdf
OK
redis db2:6381[2]> ttl test
(integer) 19
redis db2:6381[2]> expire test 60
(integer) 1
redis db2:6381[2]> ttl test
(integer) 59

check-host.net uses Redis

check-host.net is an online tool for checking availability of websites, DNS records etc..

Here is a little article about its internals http://showmetheco.de/articles/2011/1/using-perl-mojolicious-and-redis-in-a-real-world-asynchronous-application.html

Reconsider preferred scala client

Not to be a jerk, but I'm curious why scala-redis is considered the preferred client for Scala. It seems like a decent client, but I really think that redis-client-scala-netty has much better features: async io, typing, binary safe values, protocol pipelining, connection multiplexing, implicit conversions...

localshow.tv is using redis

...and it is a lifesaver. Previously, we were storing JSON in memcached, but the availability of lists and hashes as native objects is faster, uses less memory, and is cleaner to code. Redis 2.2 fixes the issue with expiring volatile objects, so now lists can be popped while expiring in 24 hours.

At the moment, I don't know of any missing features... Redis nails it all. Insane. Excellent work, and thanks!

Outdated article in documentation - "15 minutes introduction to Redis data types"

On page http://redis.io/topics/data-types-intro is a really outdated part of documentation, pls. find sentence "Redis 1.4 will add the Hash type." and check the text around.

License

I'm implementing JavaScript library that wraps the IndexedDB interface of modern browsers with an interface that was inspired by redis.

Is there any license information for the redis documentation? I'd like to use the short description of some redis commands for my project, as the behaviour is nearly identical.

rpush slow when list-max-ziplist-entries is big

Very simple code:

require 'redis'
redis = Redis.new(:timeout => 60)
a = Array.new(ARGV[0].to_i, 1)
redis.flushall
t = Time.now
10.times{|i| redis.rpush i, a}
t1 = Time.now
memory = redis.info['used_memory_human']
print "Tooked #{t1 - t} seconds to serialize #{a.size} values and spent #{memory} of memory\n"

Results:

root@pesta:# ruby test.rb 10000
Tooked 0.202587693 seconds to serialize 10000 values and spent 1.12M of memory
root@pesta:# ruby test.rb 20000
Tooked 0.385018421 seconds to serialize 20000 values and spent 1.51M of memory
root@pesta:# ruby test.rb 40000
Tooked 0.776276837 seconds to serialize 40000 values and spent 2.33M of memory
root@pesta:# ruby test.rb 60000
Tooked 1.161096079 seconds to serialize 60000 values and spent 3.30M of memory
root@pesta:# ruby test.rb 80000
Tooked 58.732304464 seconds to serialize 80000 values and spent 4.24M of memory
root@pesta:# ruby test.rb 65536
Tooked 1.265133161 seconds to serialize 65536 values and spent 3.54M of memory
root@pesta:~# ruby test.rb 70000
Tooked 18.679042551 seconds to serialize 70000 values and spent 3.77M of memory

redis.conf is very basic:

loglevel verbose
list-max-ziplist-entries 1048576
list-max-ziplist-value 256

redis version:
Redis server v=2.5.11 sha=00000000:0 malloc=jemalloc-3.0.0 bits=32

Suggestions ? Maybe I'm missing something here, but I think the performance should't degrade like this.

AuthorityLabs

We use redis to manage our keyword and domain processing.

Leatherbound uses redis

Hi, just wanted to let you know that http://leatherbound.me is using redis as its primary data store.

site using redis

The redis homepage "if you are using redis, let us know" link sent me here. graphbug.com uses redis for all of its data.

thanks,
Ian

Sina weibo (like twitter) use redis to do a lot of things

http://t.sina.com.cn we use redis to store follower, following and many other things.

but when we want to store counts in redis (eg, rt counts, tweet counts), we found it cost too much ext memories compare to memcache . do you have plan to support int keys and value ? or any other suggestion?

EVALSHA missing from commands.json

EVALSHA is not described in the list of command from commands.json

Data-types link should be added to the Documentation page

On the Documentation page, the link to Data types is missing.
I found it through Google search. The link should be added under Topics.
Similarly, some other topics are missing from the Document page.

chicken-scheme client for redis

Hi,

Here is another redis client for your collection:

https://github.com/carld/redis-client.egg

More documentation is here:

http://wiki.call-cc.org/eggref/4/redis-client

chicken-scheme users can install it with: chicken-install -s redis-client

You are welcome to add it to the list of clients on the redis.io website.

The license is BSD style.

Thanks

www.shopsquad.com uses Redis

Hey guys, we use Redis for our recently-launched startup and we think it's great. Keep up the good work!

Configure Travis

Travis should build redis-doc to prevent pull requests like #195.

www.thematchfixer.com uses redis

http://www.thematchfixer.com is a general purpose betting engine which I have developed using Sinatra / Redis /Thin / nginx. The main idea was to develop a game which would be very real-time, and Redis was the obvious choice given the speed !! You can take the engine for a spin starting the 19th of feb (when the cricket world cup starts) and if things go great I plan to generalize the engine so that it could be compatible for most of the popular sports.

Cheers!
Sanjay

StackOverflow uses Redis

Hi,
Just read that StackOverflow uses Redis

http://meta.stackoverflow.com/questions/69164/does-stackoverflow-use-caching-and-if-so-how/69172#69172

greets,
mj

Please delete this issue.

.