From ab72b4833d2054231437acccec36f32f07290075 Mon Sep 17 00:00:00 2001 From: antirez Date: Fri, 14 May 2010 18:48:33 +0200 Subject: [PATCH] minor fixes to the new test suite, html doc updated --- Makefile | 5 ++-- doc/AppendOnlyFileHowto.html | 8 +++--- doc/CommandReference.html | 11 +++++--- doc/ExpireCommand.html | 22 ++++++++++++++-- doc/FAQ.html | 5 ++-- doc/IncrCommand.html | 3 +-- doc/IntroductionToRedisDataTypes.html | 8 +++--- doc/ListCommandsSidebar.html | 2 +- doc/LrangeCommand.html | 19 +++++++++----- doc/LsetCommand.html | 3 +-- doc/QuickStart.html | 5 ++-- doc/Redis_1_2_0_Changelog.html | 8 ++++-- doc/ReplicationHowto.html | 6 +++-- doc/SaveCommand.html | 4 +-- doc/SmembersCommand.html | 3 +-- doc/SortCommand.html | 10 +++++--- doc/SortedSetCommandsSidebar.html | 2 +- doc/SponsorshipHistory.html | 2 +- doc/SponsorshipHowto.html | 37 --------------------------- doc/StringCommandsSidebar.html | 2 +- doc/TypeCommand.html | 2 ++ doc/ZrangebyscoreCommand.html | 4 +-- doc/index.html | 7 ++--- {test => tests}/assets/default.conf | 0 {test => tests}/support/redis.tcl | 0 {test => tests}/support/server.tcl | 4 +-- {test => tests}/support/test.tcl | 2 +- {test => tests}/support/tmpfile.tcl | 2 +- {test => tests}/support/util.tcl | 0 {test => tests}/test_helper.tcl | 16 ++++++------ {test => tests}/tmp/.gitignore | 0 {test => tests}/unit/auth.tcl | 0 {test => tests}/unit/basic.tcl | 0 {test => tests}/unit/expire.tcl | 0 {test => tests}/unit/other.tcl | 0 {test => tests}/unit/protocol.tcl | 0 {test => tests}/unit/sort.tcl | 0 {test => tests}/unit/type/hash.tcl | 0 {test => tests}/unit/type/list.tcl | 0 {test => tests}/unit/type/set.tcl | 0 {test => tests}/unit/type/zset.tcl | 0 41 files changed, 102 insertions(+), 100 deletions(-) delete mode 100644 doc/SponsorshipHowto.html rename {test => tests}/assets/default.conf (100%) rename {test => tests}/support/redis.tcl (100%) rename {test => tests}/support/server.tcl (97%) rename {test => tests}/support/test.tcl (91%) rename {test => tests}/support/tmpfile.tcl (93%) rename {test => tests}/support/util.tcl (100%) rename {test => tests}/test_helper.tcl (79%) rename {test => tests}/tmp/.gitignore (100%) rename {test => tests}/unit/auth.tcl (100%) rename {test => tests}/unit/basic.tcl (100%) rename {test => tests}/unit/expire.tcl (100%) rename {test => tests}/unit/other.tcl (100%) rename {test => tests}/unit/protocol.tcl (100%) rename {test => tests}/unit/sort.tcl (100%) rename {test => tests}/unit/type/hash.tcl (100%) rename {test => tests}/unit/type/list.tcl (100%) rename {test => tests}/unit/type/set.tcl (100%) rename {test => tests}/unit/type/zset.tcl (100%) diff --git a/Makefile b/Makefile index ee9ec2122..c6cbf320e 100644 --- a/Makefile +++ b/Makefile @@ -51,7 +51,6 @@ redis-cli.o: redis-cli.c fmacros.h anet.h sds.h adlist.h zmalloc.h \ redis.o: redis.c fmacros.h config.h redis.h ae.h sds.h anet.h dict.h \ adlist.h zmalloc.h lzf.h pqsort.h zipmap.h staticsymbols.h sha1.h sds.o: sds.c sds.h zmalloc.h -test.o: test.c dict2.h zipmap.o: zipmap.c zmalloc.h zmalloc.o: zmalloc.c config.h @@ -87,8 +86,8 @@ dep: staticsymbols: tclsh utils/build-static-symbols.tcl > staticsymbols.h -test: redis-server - tclsh8.5 test/test_helper.tcl +test: + tclsh8.5 tests/test_helper.tcl bench: ./redis-benchmark diff --git a/doc/AppendOnlyFileHowto.html b/doc/AppendOnlyFileHowto.html index b30a27cae..1a0e468ac 100644 --- a/doc/AppendOnlyFileHowto.html +++ b/doc/AppendOnlyFileHowto.html @@ -16,7 +16,7 @@
-AppendOnlyFileHowto: Contents
    General Information
    Log rewriting
    Wait... but how does this work?
    How durable is the append only file? +AppendOnlyFileHowto: Contents
  Append Only File HOWTO
    General Information
    Log rewriting
    Wait... but how does this work?
    How durable is the append only file?

AppendOnlyFileHowto

@@ -26,11 +26,13 @@
- = Append Only File HOWTO =

General Information

Append only file is an alternative durability option for Redis. What this mean? Let's start with some fact:

+ #sidebar RedisGuides +

Append Only File HOWTO

General Information

Append only file is an alternative durability option for Redis. What this mean? Let's start with some fact:

What is the solution? To use append only file as alternative to snapshotting. How it works?

-

Log rewriting

As you can guess... the append log file gets bigger and bigger, every time there is a new operation changing the dataset. Even if you set always the same key "mykey" to the values of "1", "2", "3", ... up to 10000000000 in the end you'll have just a single key in the dataset, just a few bytes! but how big will be the append log file? Very very big.

So Redis supports an interesting feature: it is able to rebuild the append log file, in background, without to stop processing client commands. The key is the command BGREWRITEAOF. This command basically is able to use the dataset in memory in order to rewrite the shortest sequence of commands able to rebuild the exact dataset that is currently in memory.

So from time to time when the log gets too big, try this command. It's safe as if it fails you will not lost your old log (but you can make a backup copy given that currently 1.1 is still in beta!).

Wait... but how does this work?

Basically it uses the same fork() copy-on-write trick that snapshotting already uses. This is how the algorithm works:

+

Log rewriting

As you can guess... the append log file gets bigger and bigger, every time there is a new operation changing the dataset. Even if you set always the same key "mykey" to the values of "1", "2", "3", ... up to 10000000000 in the end you'll have just a single key in the dataset, just a few bytes! but how big will be the append log file? Very very big.

So Redis supports an interesting feature: it is able to rebuild the append log file, in background, without to stop processing client commands. The key is the command BGREWRITEAOF. This command basically is able to use the dataset in memory in order to rewrite the shortest sequence of commands able to rebuild the exact dataset that is currently in memory.

So from time to time when the log gets too big, try this command. It's safe as if it fails you will not lost your old log (but you can make a backup copy given that currently 1.1 is still in beta!).

Wait... but how does this work?

Basically it uses the same fork() copy-on-write trick that snapshotting already uses. This is how the algorithm works:

How durable is the append only file?

Check redis.conf, you can configure how many times Redis will fsync() data on disk. There are three options:

Warning: by default Redis will fsync() after every command! This is because the Redis authors want to ship a default configuration that is the safest pick. But the best compromise for most datasets is to fsync() one time every second. +
diff --git a/doc/CommandReference.html b/doc/CommandReference.html index ec0376d49..4d4336242 100644 --- a/doc/CommandReference.html +++ b/doc/CommandReference.html @@ -16,7 +16,7 @@
-CommandReference: Contents
    Connection handling
    Commands operating on all the kind of values
    Commands operating on string values
    Commands operating on lists
    Commands operating on sets
    Commands operating on sorted sets (zsets, Redis version >
    Sorting
    Persistence control commands
    Remote server control commands +CommandReference: Contents
    Connection handling
    Commands operating on all the kind of values
    Commands operating on string values
    Commands operating on lists
    Commands operating on sets
    Commands operating on sorted sets (zsets, Redis version >
    Commands operating on hashes
    Sorting
    Transactions
    Publish/Subscribe
    Persistence control commands
    Remote server control commands

CommandReference

@@ -28,11 +28,14 @@
= Redis Command Reference =

Every command name links to a specific wiki page describing the behavior of the command.

Connection handling

  • QUIT close the connection
  • AUTH simple password authentication if enabled

Commands operating on all the kind of values

  • EXISTS key test if a key exists
  • DEL key delete a key
  • TYPE key return the type of the value stored at key
  • KEYS pattern return all the keys matching a given pattern
  • RANDOMKEY return a random key from the key space
  • RENAME oldname newname rename the old key in the new one, destroing the newname key if it already exists
  • RENAMENX oldname newname rename the old key in the new one, if the newname key does not already exist
  • DBSIZE return the number of keys in the current db
  • EXPIRE set a time to live in seconds on a key
  • TTL get the time to live in seconds of a key
  • SELECT index Select the DB having the specified index
  • MOVE key dbindex Move the key from the currently selected DB to the DB having as index dbindex
  • FLUSHDB Remove all the keys of the currently selected DB
  • FLUSHALL Remove all the keys from all the databases
-

Commands operating on string values

  • SET key value set a key to a string value
  • GET key return the string value of the key
  • GETSET key value set a key to a string returning the old value of the key
  • MGET key1 key2 ... keyN multi-get, return the strings values of the keys
  • SETNX key value set a key to a string value if the key does not exist
  • MSET key1 value1 key2 value2 ... keyN valueN set a multiple keys to multiple values in a single atomic operation
  • MSETNX key1 value1 key2 value2 ... keyN valueN set a multiple keys to multiple values in a single atomic operation if none of the keys already exist
  • INCR key increment the integer value of key
  • INCRBY key integer increment the integer value of key by integer
  • DECR key decrement the integer value of key
  • DECRBY key integer decrement the integer value of key by integer
-

Commands operating on lists

  • RPUSH key value Append an element to the tail of the List value at key
  • LPUSH key value Append an element to the head of the List value at key
  • LLEN key Return the length of the List value at key
  • LRANGE key start end Return a range of elements from the List at key
  • LTRIM key start end Trim the list at key to the specified range of elements
  • LINDEX key index Return the element at index position from the List at key
  • LSET key index value Set a new value as the element at index position of the List at key
  • LREM key count value Remove the first-N, last-N, or all the elements matching value from the List at key
  • LPOP key Return and remove (atomically) the first element of the List at key
  • RPOP key Return and remove (atomically) the last element of the List at key
  • RPOPLPUSH srckey dstkey Return and remove (atomically) the last element of the source List stored at _srckey_ and push the same element to the destination List stored at _dstkey_
+

Commands operating on string values

  • SET key value set a key to a string value
  • GET key return the string value of the key
  • GETSET key value set a key to a string returning the old value of the key
  • MGET key1 key2 ... keyN multi-get, return the strings values of the keys
  • SETNX key value set a key to a string value if the key does not exist
  • SETEX key time value Set+Expire combo command
  • MSET key1 value1 key2 value2 ... keyN valueN set a multiple keys to multiple values in a single atomic operation
  • MSETNX key1 value1 key2 value2 ... keyN valueN set a multiple keys to multiple values in a single atomic operation if none of the keys already exist
  • INCR key increment the integer value of key
  • INCRBY key integer increment the integer value of key by integer
  • DECR key decrement the integer value of key
  • DECRBY key integer decrement the integer value of key by integer
  • APPEND key value append the specified string to the string stored at key
  • SUBSTR key start end return a substring out of a larger string
+

Commands operating on lists

  • RPUSH key value Append an element to the tail of the List value at key
  • LPUSH key value Append an element to the head of the List value at key
  • LLEN key Return the length of the List value at key
  • LRANGE key start end Return a range of elements from the List at key
  • LTRIM key start end Trim the list at key to the specified range of elements
  • LINDEX key index Return the element at index position from the List at key
  • LSET key index value Set a new value as the element at index position of the List at key
  • LREM key count value Remove the first-N, last-N, or all the elements matching value from the List at key
  • LPOP key Return and remove (atomically) the first element of the List at key
  • RPOP key Return and remove (atomically) the last element of the List at key
  • BLPOP key1 key2 ... keyN timeout Blocking LPOP
  • BRPOP key1 key2 ... keyN timeout Blocking RPOP
  • RPOPLPUSH srckey dstkey Return and remove (atomically) the last element of the source List stored at _srckey_ and push the same element to the destination List stored at _dstkey_

Commands operating on sets

  • SADD key member Add the specified member to the Set value at key
  • SREM key member Remove the specified member from the Set value at key
  • SPOP key Remove and return (pop) a random element from the Set value at key
  • SMOVE srckey dstkey member Move the specified member from one Set to another atomically
  • SCARD key Return the number of elements (the cardinality) of the Set at key
  • SISMEMBER key member Test if the specified value is a member of the Set at key
  • SINTER key1 key2 ... keyN Return the intersection between the Sets stored at key1, key2, ..., keyN
  • SINTERSTORE dstkey key1 key2 ... keyN Compute the intersection between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey
  • SUNION key1 key2 ... keyN Return the union between the Sets stored at key1, key2, ..., keyN
  • SUNIONSTORE dstkey key1 key2 ... keyN Compute the union between the Sets stored at key1, key2, ..., keyN, and store the resulting Set at dstkey
  • SDIFF key1 key2 ... keyN Return the difference between the Set stored at key1 and all the Sets key2, ..., keyN
  • SDIFFSTORE dstkey key1 key2 ... keyN Compute the difference between the Set key1 and all the Sets key2, ..., keyN, and store the resulting Set at dstkey
  • SMEMBERS key Return all the members of the Set value at key
  • SRANDMEMBER key Return a random member of the Set value at key
-

Commands operating on sorted sets (zsets, Redis version >

1.1) ==

  • ZADD key score member Add the specified member to the Sorted Set value at key or update the score if it already exist
  • ZREM key member Remove the specified member from the Sorted Set value at key
  • ZINCRBY key increment member If the member already exists increment its score by _increment_, otherwise add the member setting _increment_ as score
  • ZRANGE key start end Return a range of elements from the sorted set at key
  • ZREVRANGE key start end Return a range of elements from the sorted set at key, exactly like ZRANGE, but the sorted set is ordered in traversed in reverse order, from the greatest to the smallest score
  • ZRANGEBYSCORE key min max Return all the elements with score >= min and score <= max (a range query) from the sorted set
  • ZCARD key Return the cardinality (number of elements) of the sorted set at key
  • ZSCORE key element Return the score associated with the specified element of the sorted set at key
  • ZREMRANGEBYSCORE key min max Remove all the elements with score >= min and score <= max from the sorted set
+

Commands operating on sorted sets (zsets, Redis version >

1.1) ==

  • ZADD key score member Add the specified member to the Sorted Set value at key or update the score if it already exist
  • ZREM key member Remove the specified member from the Sorted Set value at key
  • ZINCRBY key increment member If the member already exists increment its score by _increment_, otherwise add the member setting _increment_ as score
  • ZRANK key member Return the rank (or index) or _member_ in the sorted set at _key_, with scores being ordered from low to high
  • ZREVRANK key member Return the rank (or index) or _member_ in the sorted set at _key_, with scores being ordered from high to low
  • ZRANGE key start end Return a range of elements from the sorted set at key
  • ZREVRANGE key start end Return a range of elements from the sorted set at key, exactly like ZRANGE, but the sorted set is ordered in traversed in reverse order, from the greatest to the smallest score
  • ZRANGEBYSCORE key min max Return all the elements with score >= min and score <= max (a range query) from the sorted set
  • ZCARD key Return the cardinality (number of elements) of the sorted set at key
  • ZSCORE key element Return the score associated with the specified element of the sorted set at key
  • ZREMRANGEBYRANK key min max Remove all the elements with rank >= min and rank <= max from the sorted set
  • ZREMRANGEBYSCORE key min max Remove all the elements with score >= min and score <= max from the sorted set
  • ZUNION / ZINTER dstkey N key1 ... keyN WEIGHTS w1 ... wN AGGREGATE SUM|MIN|MAX Perform a union or intersection over a number of sorted sets with optional weight and aggregate
+

Commands operating on hashes

  • HSET key field value Set the hash field to the specified value. Creates the hash if needed.
  • HGET key field Retrieve the value of the specified hash field.
  • HMSET key field1 value1 ... fieldN valueN Set the hash fields to their respective values.
  • HINCRBY key field integer Increment the integer value of the hash at _key_ on _field_ with _integer_.
  • HEXISTS key field Test for existence of a specified field in a hash
  • HDEL key field Remove the specified field from a hash
  • HLEN key Return the number of items in a hash.
  • HKEYS key Return all the fields in a hash.
  • HVALS key Return all the values in a hash.
  • HGETALL key Return all the fields and associated values in a hash.

Sorting

  • SORT key BY pattern LIMIT start end GET pattern ASC|DESC ALPHA Sort a Set or a List accordingly to the specified parameters
+

Transactions

+

Publish/Subscribe

Persistence control commands

  • SAVE Synchronously save the DB on disk
  • BGSAVE Asynchronously save the DB on disk
  • LASTSAVE Return the UNIX time stamp of the last successfully saving of the dataset on disk
  • SHUTDOWN Synchronously save the DB on disk, then shutdown the server
  • BGREWRITEAOF Rewrite the append only file in background when it gets too big

Remote server control commands

  • INFO Provide information and statistics about the server
  • MONITOR Dump all the received requests in real time
  • SLAVEOF Change the replication settings
diff --git a/doc/ExpireCommand.html b/doc/ExpireCommand.html index d5baeca23..a3dbbe5be 100644 --- a/doc/ExpireCommand.html +++ b/doc/ExpireCommand.html @@ -16,7 +16,7 @@
-ExpireCommand: Contents
  EXPIRE _key_ _seconds_
  EXPIREAT _key_ _unixtime_ (Redis >
    How the expire is removed from a key
    Restrictions with write operations against volatile keys
    Setting the timeout again on already volatile keys
    Enhanced Lazy Expiration algorithm
      Version 1.0
      Version 1.1
    Return value +ExpireCommand: Contents
  EXPIRE _key_ _seconds_
  EXPIREAT _key_ _unixtime_ (Redis >
    How the expire is removed from a key
    Restrictions with write operations against volatile keys
    Setting the timeout again on already volatile keys
    Enhanced Lazy Expiration algorithm
      Version 1.0
      Version 1.1
    Return value
    FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?

ExpireCommand

@@ -57,8 +57,26 @@ OK

Return value

Integer reply, specifically:

 1: the timeout was set.
 0: the timeout was not set since the key already has an associated timeout, or the key does not exist.
+

FAQ: Can you explain better why Redis deletes keys with an EXPIRE on write operations?

+Ok let's start with the problem: +
+redis> set a 100
+OK
+redis> expire a 360
+(integer) 1
+redis> incr a
+(integer) 1
- +I set a key to the value of 100, then set an expire of 360 seconds, and then incremented the key (before the 360 timeout expired of course). The obvious result would be: 101, instead the key is set to the value of 1. Why? +There is a very important reason involving the Append Only File and Replication. Let's rework a bit hour example adding the notion of time to the mix: +
+SET a 100
+EXPIRE a 5
+... wait 10 seconds ...
+INCR a
+
+Imagine a Redis version that does not implement the "Delete keys with an expire set on write operation" semantic. +Running the above example with the 10 seconds pause will lead to 'a' being set to the value of 1, as it no longer exists when INCR is called 10 seconds later.

Instead if we drop the 10 seconds pause, the result is that 'a' is set to 101.

And in the practice timing changes! For instance the client may wait 10 seconds before INCR, but the sequence written in the Append Only File (and later replayed-back as fast as possible when Redis is restarted) will not have the pause. Even if we add a timestamp in the AOF, when the time difference is smaller than our timer resolution, we have a race condition.

The same happens with master-slave replication. Again, consider the example above: the client will use the same sequence of commands without the 10 seconds pause, but the replication link will slow down for a few seconds due to a network problem. Result? The master will contain 'a' set to 101, the slave 'a' set to 1.

The only way to avoid this but at the same time have reliable non time dependent timeouts on keys is to destroy volatile keys when a write operation is attempted against it.

After all Redis is one of the rare fully persistent databases that will give you EXPIRE. This comes to a cost :)
diff --git a/doc/FAQ.html b/doc/FAQ.html index 6d0246dc3..7c012b2cf 100644 --- a/doc/FAQ.html +++ b/doc/FAQ.html @@ -16,7 +16,7 @@
-FAQ: Contents
  Isn't this key-value thing just hype?
  Can I backup a Redis DB while the server is working?
  What's the Redis memory footprint?
  I like Redis high level operations and features, but I don't like it takes everything in memory and I can't have a dataset larger the memory. Plans to change this?
  Why Redis takes the whole dataset in RAM?
  If my dataset is too big for RAM and I don't want to use consistent hashing or other ways to distribute the dataset across different nodes, what I can do to use Redis anyway?
  Do you plan to implement Virtual Memory in Redis? Why don't just let the Operating System handle it for you?
  I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!
  What happens if Redis runs out of memory?
  How much time it takes to load a big database at server startup?
  Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!
  Are Redis on disk snapshots atomic?
  Redis is single threaded, how can I exploit multiple CPU / cores?
  I'm using some form of key hashing for partitioning, but what about SORT BY?
  What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?
  What Redis means actually?
  Why did you started the Redis project? +FAQ: Contents
  Isn't this key-value thing just hype?
  Can I backup a Redis DB while the server is working?
  What's the Redis memory footprint?
  I like Redis high level operations and features, but I don't like it takes everything in memory and I can't have a dataset larger the memory. Plans to change this?
  Why Redis takes the whole dataset in RAM?
  If my dataset is too big for RAM and I don't want to use consistent hashing or other ways to distribute the dataset across different nodes, what I can do to use Redis anyway?
  Do you plan to implement Virtual Memory in Redis? Why don't just let the Operating System handle it for you?
  Is there something I can do to lower the Redis memory usage?
  I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!
  What happens if Redis runs out of memory?
  Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?
  How much time it takes to load a big database at server startup?
  Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!
  Are Redis on disk snapshots atomic?
  Redis is single threaded, how can I exploit multiple CPU / cores?
  I'm using some form of key hashing for partitioning, but what about SORT BY?
  What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?
  What Redis means actually?
  Why did you started the Redis project?

FAQ

@@ -58,10 +58,9 @@ Redis for the same objects. This happens because when data is in memory is full of pointers, reference counters and other metadata. Add to this malloc fragmentation and need to return word-aligned chunks of memory and you have a clear picture of what happens. So this means to -have 10 times the I/O between memory and disk than otherwise needed.

I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!

This may happen and it's prefectly ok. Redis objects are small C structures allocated and freed a lot of times. This costs a lot of CPU so instead of being freed, released objects are taken into a free list and reused when needed. This memory is taken exactly by this free objects ready to be reused.

What happens if Redis runs out of memory?

With modern operating systems malloc() returning NULL is not common, usually the server will start swapping and Redis performances will be disastrous so you'll know it's time to use more Redis servers or get more RAM.

The INFO command (work in progress in this days) will report the amount of memory Redis is using so you can write scripts that monitor your Redis servers checking for critical conditions.

You can also use the "maxmemory" option in the config file to put a limit to the memory Redis can use. If this limit is reached Redis will start to reply with an error to write commands (but will continue to accept read-only commands).

How much time it takes to load a big database at server startup?

Just an example on normal hardware: It takes about 45 seconds to restore a 2 GB database on a fairly standard system, no RAID. This can give you some kind of feeling about the order of magnitude of the time needed to load data when you restart the server.

Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!

Short answer: echo 1 > /proc/sys/vm/overcommit_memory :)

And now the long one:

Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) that is an exact copy of the parent. The child process dumps the DB on disk and finally exits. In theory the child should use as much memory as the parent being a copy, but actually thanks to the copy-on-write semantic implemented by most modern operating systems the parent and child process will share the common memory pages. A page will be duplicated only when it changes in the child or in the parent. Since in theory all the pages may change while the child process is saving, Linux can't tell in advance how much memory the child will take, so if the overcommit_memory setting is set to zero fork will fail unless there is as much free RAM as required to really duplicate all the parent memory pages, with the result that if you have a Redis dataset of 3 GB and just 2 GB of free memory it will fail.

Setting overcommit_memory to 1 says Linux to relax and perform the fork in a more optimistic allocation fashion, and this is indeed what you want for Redis.

Are Redis on disk snapshots atomic?

Yes, redis background saving process is always fork(2)ed when the server is outside of the execution of a command, so every command reported to be atomic in RAM is also atomic from the point of view of the disk snapshot.

Redis is single threaded, how can I exploit multiple CPU / cores?

Simply start multiple instances of Redis in different ports in the same box and threat them as different servers! Given that Redis is a distributed database anyway in order to scale you need to think in terms of multiple computational units. At some point a single box may not be enough anyway.

In general key-value databases are very scalable because of the property that different keys can stay on different servers independently.

In Redis there are client libraries such Redis-rb (the Ruby client) that are able to handle multiple servers automatically using consistent hashing. We are going to implement consistent hashing in all the other major client libraries. If you use a different language you can implement it yourself otherwise just hash the key before to SET / GET it from a given server. For example imagine to have N Redis servers, server-0, server-1, ..., server-N. You want to store the key "foo", what's the right server where to put "foo" in order to distribute keys evenly among different servers? Just perform the crc = CRC32("foo"), then servernum = crc % N (the rest of the division for N). This will give a number between 0 and N-1 for every key. Connect to this server and store the key. The same for gets.

This is a basic way of performing key partitioning, consistent hashing is much better and this is why after Redis 1.0 will be released we'll try to implement this in every widely used client library starting from Python and PHP (Ruby already implements this support).

I'm using some form of key hashing for partitioning, but what about SORT BY?

With SORT BY you need that all the weight keys are in the same Redis instance of the list/set you are trying to sort. In order to make this possible we developed a concept called key tags. A key tag is a special pattern inside a key that, if preset, is the only part of the key hashed in order to select the server for this key. For example in order to hash the key "foo" I simply perform the CRC32 checksum of the whole string, but if this key has a pattern in the form of the characters {...} I only hash this substring. So for example for the key "foo{bared}" the key hashing code will simply perform the CRC32 of "bared". This way using key tags you can ensure that related keys will be stored on the same Redis instance just using the same key tag for all this keys. Redis-rb already implements key tags.

What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?

In theory Redis can handle up to 232 keys, and was tested in practice to handle at least 150 million of keys per instance. We are working in order to experiment with larger values.

Every list, set, and ordered set, can hold 232 elements.

Actually Redis internals are ready to allow up to 264 elements but the current disk dump format don't support this, and there is a lot time to fix this issues in the future as currently even with 128 GB of RAM it's impossible to reach 232 elements.

What Redis means actually?

Redis means two things: +have 10 times the I/O between memory and disk than otherwise needed.

Is there something I can do to lower the Redis memory usage?

Yes, try to compile it with 32 bit target if you are using a 64 bit box.

If you are using Redis >= 1.3, try using the Hash data type, it can save a lot of memory.

If you are using hashes or any other type with values bigger than 128 bytes try also this to lower the RSS usage (Resident Set Size): EXPORT MMAP_THRESHOLD=4096

I have an empty Redis server but INFO and logs are reporting megabytes of memory in use!

This may happen and it's prefectly ok. Redis objects are small C structures allocated and freed a lot of times. This costs a lot of CPU so instead of being freed, released objects are taken into a free list and reused when needed. This memory is taken exactly by this free objects ready to be reused.

What happens if Redis runs out of memory?

With modern operating systems malloc() returning NULL is not common, usually the server will start swapping and Redis performances will be disastrous so you'll know it's time to use more Redis servers or get more RAM.

The INFO command (work in progress in this days) will report the amount of memory Redis is using so you can write scripts that monitor your Redis servers checking for critical conditions.

You can also use the "maxmemory" option in the config file to put a limit to the memory Redis can use. If this limit is reached Redis will start to reply with an error to write commands (but will continue to accept read-only commands).

Does Redis use more memory running in 64 bit boxes? Can I use 32 bit Redis in 64 bit systems?

Redis uses a lot more memory when compiled for 64 bit target, especially if the dataset is composed of many small keys and values. Such a database will, for instance, consume 50 MB of RAM when compiled for the 32 bit target, and 80 MB for 64 bit! That's a big difference.

You can run 32 bit Redis binaries in a 64 bit Linux and Mac OS X system without problems. For OS X just use make 32bit. For Linux instead, make sure you have libc6-dev-i386 installed, then use make 32bit if you are using the latest Git version. Instead for Redis <= 1.2.2 you have to edit the Makefile and replace "-arch i386" with "-m32".

If your application is already able to perform application-level sharding, it is very advisable to run N instances of Redis 32bit against a big 64 bit Redis box (with more than 4GB of RAM) instead than a single 64 bit instance, as this is much more memory efficient.

How much time it takes to load a big database at server startup?

Just an example on normal hardware: It takes about 45 seconds to restore a 2 GB database on a fairly standard system, no RAID. This can give you some kind of feeling about the order of magnitude of the time needed to load data when you restart the server.

Background saving is failing with a fork() error under Linux even if I've a lot of free RAM!

Short answer: echo 1 > /proc/sys/vm/overcommit_memory :)

And now the long one:

Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) that is an exact copy of the parent. The child process dumps the DB on disk and finally exits. In theory the child should use as much memory as the parent being a copy, but actually thanks to the copy-on-write semantic implemented by most modern operating systems the parent and child process will share the common memory pages. A page will be duplicated only when it changes in the child or in the parent. Since in theory all the pages may change while the child process is saving, Linux can't tell in advance how much memory the child will take, so if the overcommit_memory setting is set to zero fork will fail unless there is as much free RAM as required to really duplicate all the parent memory pages, with the result that if you have a Redis dataset of 3 GB and just 2 GB of free memory it will fail.

Setting overcommit_memory to 1 says Linux to relax and perform the fork in a more optimistic allocation fashion, and this is indeed what you want for Redis.

Are Redis on disk snapshots atomic?

Yes, redis background saving process is always fork(2)ed when the server is outside of the execution of a command, so every command reported to be atomic in RAM is also atomic from the point of view of the disk snapshot.

Redis is single threaded, how can I exploit multiple CPU / cores?

Simply start multiple instances of Redis in different ports in the same box and threat them as different servers! Given that Redis is a distributed database anyway in order to scale you need to think in terms of multiple computational units. At some point a single box may not be enough anyway.

In general key-value databases are very scalable because of the property that different keys can stay on different servers independently.

In Redis there are client libraries such Redis-rb (the Ruby client) that are able to handle multiple servers automatically using consistent hashing. We are going to implement consistent hashing in all the other major client libraries. If you use a different language you can implement it yourself otherwise just hash the key before to SET / GET it from a given server. For example imagine to have N Redis servers, server-0, server-1, ..., server-N. You want to store the key "foo", what's the right server where to put "foo" in order to distribute keys evenly among different servers? Just perform the crc = CRC32("foo"), then servernum = crc % N (the rest of the division for N). This will give a number between 0 and N-1 for every key. Connect to this server and store the key. The same for gets.

This is a basic way of performing key partitioning, consistent hashing is much better and this is why after Redis 1.0 will be released we'll try to implement this in every widely used client library starting from Python and PHP (Ruby already implements this support).

I'm using some form of key hashing for partitioning, but what about SORT BY?

With SORT BY you need that all the weight keys are in the same Redis instance of the list/set you are trying to sort. In order to make this possible we developed a concept called key tags. A key tag is a special pattern inside a key that, if preset, is the only part of the key hashed in order to select the server for this key. For example in order to hash the key "foo" I simply perform the CRC32 checksum of the whole string, but if this key has a pattern in the form of the characters {...} I only hash this substring. So for example for the key "foo{bared}" the key hashing code will simply perform the CRC32 of "bared". This way using key tags you can ensure that related keys will be stored on the same Redis instance just using the same key tag for all this keys. Redis-rb already implements key tags.

What is the maximum number of keys a single Redis instance can hold? and what the max number of elements in a List, Set, Ordered Set?

In theory Redis can handle up to 232 keys, and was tested in practice to handle at least 150 million of keys per instance. We are working in order to experiment with larger values.

Every list, set, and ordered set, can hold 232 elements.

Actually Redis internals are ready to allow up to 264 elements but the current disk dump format don't support this, and there is a lot time to fix this issues in the future as currently even with 128 GB of RAM it's impossible to reach 232 elements.

What Redis means actually?

Redis means two things:

Why did you started the Redis project?

In order to scale LLOOGG. But after I got the basic server working I liked the idea to share the work with other guys, and Redis was turned into an open source project. -
diff --git a/doc/IncrCommand.html b/doc/IncrCommand.html index b2b35499c..5479e5f93 100644 --- a/doc/IncrCommand.html +++ b/doc/IncrCommand.html @@ -33,8 +33,7 @@ Time complexity: O(1)
Increment or decrement the number stored at key by one. If the key doesnot exist or contains a value of a wrong type, set the key to thevalue of "0" before to perform the increment or decrement operation.
INCRBY and DECRBY work just like INCR and DECR but instead toincrement/decrement by 1 the increment/decrement is integer.
INCR commands are limited to 64 bit signed integers.
-

Return value

Integer reply, this commands will reply with the new value of key after the increment or decrement. - +Note: this is actually a string operation, that is, in Redis there are not "integer" types. Simply the string stored at the key is parsed as a base 10 64 bit signed integer, incremented, and then converted back as a string.

Return value

Integer reply, this commands will reply with the new value of key after the increment or decrement. diff --git a/doc/IntroductionToRedisDataTypes.html b/doc/IntroductionToRedisDataTypes.html index 2bba4091c..26b2ba19f 100644 --- a/doc/IntroductionToRedisDataTypes.html +++ b/doc/IntroductionToRedisDataTypes.html @@ -16,7 +16,7 @@
-IntroductionToRedisDataTypes: Contents
    Redis keys
    The string type
    The List type
      First steps with Redis lists
      Pushing IDs instead of the actual data in Redis lists
    Redis Sets
    A digression. How to get unique identifiers for strings
    Sorted sets
      Operating on ranges
      Back to the reddit example
      Updating the scores of a sorted set +IntroductionToRedisDataTypes: Contents
  A fifteen minutes introduction to Redis data types
    Redis keys
    The string type
    The List type
      First steps with Redis lists
      Pushing IDs instead of the actual data in Redis lists
    Redis Sets
    A digression. How to get unique identifiers for strings
    Sorted sets
      Operating on ranges
      Back to the reddit example
      Updating the scores of a sorted set

IntroductionToRedisDataTypes

@@ -26,7 +26,8 @@
- = A fifteen minutes introduction to Redis data types =

As you already probably know Redis is not a plain key-value store, actually it is a data structures server, supporting different kind of values. That is, you can't just set strings as values of keys. All the following data types are supported as values:

+ #sidebar RedisGuides +

A fifteen minutes introduction to Redis data types

As you already probably know Redis is not a plain key-value store, actually it is a data structures server, supporting different kind of values. That is, you can't just set strings as values of keys. All the following data types are supported as values:

It's not always trivial to grasp how this data types work and what to use in order to solve a given problem from the Redis command reference, so this document is a crash course to Redis data types and their most used patterns.

For all the examples we'll use the redis-cli utility, that's a simple but handy command line utility to issue commands against the Redis server.

Redis keys

Before to start talking about the different kind of values supported by Redis it is better to start saying that keys are not binary safe strings in Redis, but just strings not containing a space or a newline character. For instance "foo" or "123456789" or "foo_bar" are valid keys, while "hello world" or "hello\n" are not.

Actually there is nothing inside the Redis internals preventing the use of binary keys, it's just a matter of protocol, and actually the new protocol introduced with Redis 1.2 (1.2 betas are 1.1.x) in order to implement commands like MSET, is totally binary safe. Still for now consider this as an hard limit as the database is only tested with "normal" keys.

A few other rules about keys:

The string type

This is the simplest Redis type. If you use only this type, Redis will be something like a memcached server with persistence.

Let's play a bit with the string type:

 $ ./redis-cli set mykey "my binary safe value"
@@ -42,7 +43,7 @@ $ ./redis-cli incr counter
 (integer) 102
 $ ./redis-cli incrby counter 10
 (integer) 112
-
The INCR command parses the string value as an integer, increments it by one, and finally sets the obtained value as the new string value. There are other similar commands like INCRBY, DECR and DECRBY. Actually internally it's always the same command, acting in a slightly different way.

What means that INCR is atomic? That even multiple clients issuing INCR against the same key will never incur into a race condition. For instance it can't never happen that client 1 read "10", client 2 read "10" at the same time, both increment to 11, and set the new value of 11. The final value will always be of 12 ad the read-increment-set operation is performed while all the other clients are not executing a command at the same time.

Another interesting operation on string is the GETSET command, that does just what its name suggests: Set a key to a new value, returning the old value, as result. Why this is useful? Example: you have a system that increments a Redis key using the INCR command every time your web site receives a new visit. You want to collect this information one time every hour, without loosing a single key. You can GETSET the key assigning it the new value of "0" and reading the old value back.

The List type

To explain the List data type it's better to start with a little of theory, as the term List is often used in an improper way by information technology folks. For instance "Python Lists" are not what the name may suggest (Linked Lists), but them are actually Arrays (the same data type is called Array in Ruby actually).

From a very general point of view a List is just a sequence of ordered elements: 10,20,1,2,3 is a list, but when a list of items is implemented using an Array and when instead a Linked List is used for the implementation, the properties change a lot.

Redis lists are implemented via Linked Lists, this means that even if you have million of elements inside a list, the operation of adding a new element in the head or in the tail of the list is performed in constant time. Adding a new element with the LPOP command to the head of a ten elements list is the same speed as adding an element to the head of a 10 million elements list.

What's the downside? That accessing an element by index is very fast in lists implemented with an Array and not so fast in lists implemented by linked lists.

Redis Lists are implemented with linked lists because for a database system is crucial to be able to add elements to a very long list in a very fast way. Another strong advantage is, as you'll see in a moment, that Redis Lists can be taken at constant length in constant time.

First steps with Redis lists

The LPUSH command add a new element into a list, on the left (on head), while the RPUSH command add a new element into alist, ot the right (on tail). Finally the LRANGE command extract ranges of elements from lists:

+
The INCR command parses the string value as an integer, increments it by one, and finally sets the obtained value as the new string value. There are other similar commands like INCRBY, DECR and DECRBY. Actually internally it's always the same command, acting in a slightly different way.

What means that INCR is atomic? That even multiple clients issuing INCR against the same key will never incur into a race condition. For instance it can't never happen that client 1 read "10", client 2 read "10" at the same time, both increment to 11, and set the new value of 11. The final value will always be of 12 ad the read-increment-set operation is performed while all the other clients are not executing a command at the same time.

Another interesting operation on string is the GETSET command, that does just what its name suggests: Set a key to a new value, returning the old value, as result. Why this is useful? Example: you have a system that increments a Redis key using the INCR command every time your web site receives a new visit. You want to collect this information one time every hour, without loosing a single key. You can GETSET the key assigning it the new value of "0" and reading the old value back.

The List type

To explain the List data type it's better to start with a little of theory, as the term List is often used in an improper way by information technology folks. For instance "Python Lists" are not what the name may suggest (Linked Lists), but them are actually Arrays (the same data type is called Array in Ruby actually).

From a very general point of view a List is just a sequence of ordered elements: 10,20,1,2,3 is a list, but when a list of items is implemented using an Array and when instead a Linked List is used for the implementation, the properties change a lot.

Redis lists are implemented via Linked Lists, this means that even if you have million of elements inside a list, the operation of adding a new element in the head or in the tail of the list is performed in constant time. Adding a new element with the LPUSH command to the head of a ten elements list is the same speed as adding an element to the head of a 10 million elements list.

What's the downside? That accessing an element by index is very fast in lists implemented with an Array and not so fast in lists implemented by linked lists.

Redis Lists are implemented with linked lists because for a database system is crucial to be able to add elements to a very long list in a very fast way. Another strong advantage is, as you'll see in a moment, that Redis Lists can be taken at constant length in constant time.

First steps with Redis lists

The LPUSH command add a new element into a list, on the left (on head), while the RPUSH command add a new element into alist, ot the right (on tail). Finally the LRANGE command extract ranges of elements from lists:

 $ ./redis-cli rpush messages "Hello how are you?"
 OK
 $ ./redis-cli rpush messages "Fine thanks. I'm having fun with Redis"
@@ -142,6 +143,7 @@ $ ./redis-cli zrangebyscore hackers -inf 1950
 $ ./redis-cli zremrangebyscore hackers 1940 1960
 (integer) 2
ZREMRANGEBYSCORE is not the best command name, but it can be very useful, and returns the number of removed elements.

Back to the reddit example

For the last time, back to the Reddit example. Now we have a decent plan to populate a sorted set in order to generate the home page. A sorted set can contain all the news that are not older than a few days (we remove old entries from time to time using ZREMRANGEBYSCORE). A background job gets all the elements from this sorted set, get the user votes and the time of the news, and compute the score to populate the reddit.home.page sorted set with the news IDs and associated scores. To show the home page we have just to perform a blazingly fast call to ZRANGE.

From time to time we'll remove too old news from the reddit.home.page sorted set as well in order for our system to work always against a limited set of news.

Updating the scores of a sorted set

Just a final note before to finish this tutorial. Sorted sets scores can be updated at any time. Just calling again ZADD against an element already included in the sorted set will update its score (and position) in O(log(N)), so sorted sets are suitable even when there are tons of updates.

This tutorial is in no way complete, this is just the basics to get started with Redis, read the Command Reference to discover a lot more.

Thanks for reading. Salvatore. +
diff --git a/doc/ListCommandsSidebar.html b/doc/ListCommandsSidebar.html index c570530f3..ae8279236 100644 --- a/doc/ListCommandsSidebar.html +++ b/doc/ListCommandsSidebar.html @@ -26,7 +26,7 @@
- == List Commands ==

+ == List Commands ==

diff --git a/doc/LrangeCommand.html b/doc/LrangeCommand.html index 293d8e8c9..28dbf890c 100644 --- a/doc/LrangeCommand.html +++ b/doc/LrangeCommand.html @@ -16,7 +16,7 @@
-LrangeCommand: Contents
  LRANGE _key_ _start_ _end_
    Return value +LrangeCommand: Contents
  LRANGE _key_ _start_ _end_
    Consistency with range functions in various programming languages
    Out-of-range indexes
    Return value

LrangeCommand

@@ -27,12 +27,17 @@
#sidebar ListCommandsSidebar

LRANGE _key_ _start_ _end_

-Time complexity: O(n) (with n being the length of the range)
Return the specified elements of the list stored at the specifiedkey. Start and end are zero-based indexes. 0 is the first elementof the list (the list head), 1 the next element and so on.
-
For example LRANGE foobar 0 2 will return the first three elementsof the list.
-
_start_ and end can also be negative numbers indicating offsetsfrom the end of the list. For example -1 is the last element ofthe list, -2 the penultimate element and so on.
-
Indexes out of range will not produce an error: if start is overthe end of the list, or start > end, an empty list is returned.If end is over the end of the list Redis will threat it just likethe last element of the list.
-

Return value

Multi bulk reply, specifically a list of elements in the specified range. - +Time complexity: O(start+n) (with n being the length of the range and start being the start offset)Return the specified elements of the list stored at the specified +key. Start and end are zero-based indexes. 0 is the first element +of the list (the list head), 1 the next element and so on.

For example LRANGE foobar 0 2 will return the first three elements +of the list.

start and end can also be negative numbers indicating offsets +from the end of the list. For example -1 is the last element of +the list, -2 the penultimate element and so on.

Consistency with range functions in various programming languages

Note that if you have a list of numbers from 0 to 100, LRANGE 0 10 will return +11 elements, that is, rightmost item is included. This may or may not be consistent with +behavior of range-related functions in your programming language of choice (think Ruby's Range.new, Array#slice or Python's range() function).

LRANGE behavior is consistent with one of Tcl.

Out-of-range indexes

Indexes out of range will not produce an error: if start is over +the end of the list, or start > end, an empty list is returned. +If end is over the end of the list Redis will threat it just like +the last element of the list.

Return value

Multi bulk reply, specifically a list of elements in the specified range.
diff --git a/doc/LsetCommand.html b/doc/LsetCommand.html index 39afd5ab8..5b833650d 100644 --- a/doc/LsetCommand.html +++ b/doc/LsetCommand.html @@ -28,8 +28,7 @@
#sidebar ListCommandsSidebar

LSET _key_ _index_ _value_

Time complexity: O(N) (with N being the length of the list)
Set the list element at index (see LINDEX for information about the_index_ argument) with the new value. Out of range indexes willgenerate an error. Note that setting the first or last elements ofthe list is O(1).
-

Return value

Status code reply - +
Similarly to other list commands accepting indexes, the index can be negative to access elements starting from the end of the list. So -1 is the last element, -2 is the penultimate, and so forth.

Return value

Status code reply
diff --git a/doc/QuickStart.html b/doc/QuickStart.html index f4b93361e..c233a1b58 100644 --- a/doc/QuickStart.html +++ b/doc/QuickStart.html @@ -16,7 +16,7 @@
-QuickStart: Contents
    Obtain the latest version
    Compile
    Run the server
    Play with the built in client
    Further reading +QuickStart: Contents
  Quick Start
    Obtain the latest version
    Compile
    Run the server
    Play with the built in client
    Further reading

QuickStart

@@ -26,7 +26,8 @@
- = Quick Start =

This quickstart is a five minutes howto on how to get started with Redis. For more information on Redis check Redis Documentation Index.

Obtain the latest version

The latest stable source distribution of Redis can be obtained at this location as a tarball.

+                    #sidebar RedisGuides
+
Quick Start
This quickstart is a five minutes howto on how to get started with Redis. For more information on Redis check Redis Documentation Index.
Obtain the latest version
The latest stable source distribution of Redis can be obtained at this location as a tarball.

 $ wget http://redis.googlecode.com/files/redis-1.02.tar.gz
 
The unstable source code, with more features but not ready for production, can be downloaded using git:

 $ git clone git://github.com/antirez/redis.git
diff --git a/doc/Redis_1_2_0_Changelog.html b/doc/Redis_1_2_0_Changelog.html
index c57f56ba0..256bee028 100644
--- a/doc/Redis_1_2_0_Changelog.html
+++ b/doc/Redis_1_2_0_Changelog.html
@@ -16,7 +16,7 @@
             
 
                 

-                    
CHANGELOG for Redis 1.1.90
  •  2009-09-10 in-memory specialized object encoding. (antirez)
  •  2009-09-17 maxmemory fixed in 64 systems for values > 4GB. (antirez)
  •  2009-10-07 multi-bulk protocol implemented. (antriez)
  •  2009-10-16 MSET and MSETNX commands implemented (antirez)
  •  2009-10-21 SRANDMEMBER added (antirez)
  •  2009-10-23 Fixed compilation in mac os x snow leopard when compiling a 32 bit binary.  (antirez)
  •  2009-10-23 New data type: Sorted sets and Z-commands (antirez)
  •  2009-10-26 Solaris fixed (Alan Harder)
  •  2009-10-29 Fixed Issue a number of open issues (antirez)
  •  2009-10-30 New persistence mode: append only file (antirez)
  •  2009-11-01 SORT STORE option (antirez)
  •  2009-11-03 redis-cli now accepts a -r (repeat) switch. (antirez)
  •  2009-11-04 masterauth option merged (Anthony Lauzon)
  •  2009-11-04 redis-test is now a better Redis citizen, testing everything against DB 9 and 10 and only if this DBs are empty. (antirez)
  •  2009-11-10 Implemented a much better lazy expiring algorithm for EXPIRE (antirez)
  •  2009-11-11 RPUSHLPOP (antirez from an idea of @ezmobius)
  •  2009-11-12 Merge git://github.com/ianxm/redis (Can't remmber what this implements, sorry)
  •  2009-11-17 multi-bulk reply support for redis-bench, LRANGE speed tests (antirez)
  •  2009-11-17 support for writev implemented. (Stefano Barbato)
  •  2009-11-19 debug mode (-D) in redis-bench (antirez)
  •  2009-11-21 SORT GET # implemented (antirez)
  •  2009-11-23 ae.c made modular, with support for epoll. (antirez)
  •  2009-11-26 background append log rebuilding (antirez)
  •  2009-11-28 Added support for kqueue. (Harish Mallipeddi)
  •  2009-11-29 SORT support for sorted sets (antirez, thanks to @tobi for the idea)

+                    
What's new in Redis 1.2
New persistence mode: Append Only File
The Append Only File is an alternative way to save your data in Redis that is fully durable! Unlike the snapshotting (default) persistence mode, where the database is saved asynchronously from time to time, the Append Only File saves every change ASAP in a text-only file that works like a journal. Redis will play back this file again at startup reloading the whole dataset back in memory. Redis Append Only File supports background Log compaction. For more info read the Append Only File HOWTO.
New data type: sorted sets
Sorted sets are collections of elements (like Sets) with an associated score (in the form of a double precision floating point number). Elements in a sorted set are taken in order, so for instance to take the greatest element is an O(1) operation. Insertion and deletion is O(log(N)). Sorted sets are implemented using a dual ported data structure consisting of an hash table and a skip list. For more information please read the Introduction To Redis Data Types.
Specialized integer objects encoding
Redis 1.2 will use less memory than Redis 1.0 for values in Strings, Lists or Sets elements that happen to be representable as 32 or 64 bit signed integers (it depends on your arch bits for the long C type). This is totally transparent form the point of view of the user, but will safe a lot of memory (30% less in datasets where there are many integers).
MSET and MSETNX
That is, setting multiple keys in one command, atomically. For more information see the MSET command wiki page.
Better Performances
  •  100x times faster SAVE and BGSAVE! There was a problem in the LZF lib configuration that is now resolved. The effect is this impressive speedup. Also the saving child will no longer use 100% of CPU.
  •  Glue output buffer and writev(). Many commands producing large outputs, like LRANGE, will now be even 10 times faster, thanks to the new output buffer gluing algorithm and the (optional) use of writev(2) syscall.
  •  Support for epool and kqueue / kevent. 10,000 clients scalability.
  •  Much better EXPIRE support, now it's possible to work with very large sets of keys expiring in very short time without to incur in memory problems (the new algorithm expires keys in an adaptive way, so will get more aggressive if there are a lot of expiring keys)

+
Solaris Support
Redis will now compile and work on Solaris without problems. Warning: the Solaris user base is very little, so Redis running on Solaris may not be as tested and stable as it is on  Linux and Mac OS X.
Support for the new generation protocol
  •  Redis is now able to accept commands in a new fully binary safe way: with the new protocol keys are binary safe, not only values, and there is no distinction between bulk commands and inline commands. This new protocol is currently used only for MSET and MSETNX but at some point it will hopefully replace the old one. See the Multi Bulk Commands section in the Redis Protocol Specification for more information.

+
A few new commands about already supported data types
  •  SRANDMEMBER
  •  The SortCommand is now supprots the STORE and GET # forms, the first can be used to save sorted lists, sets or sorted sets into keys for caching. Check the manual page for more information about the GET # form.
  •  The new RPOPLPUSH command can do many interesting magics, and a few of this are documented in the wiki page of the command.

+
Bug fixing
Of course, many bugs are now fixed, and I bet, a few others introduced: this is how software works after all, so make sure to report issues in the Redis mailing list or in the Google Code issues tracker.

Enjoy!
+antirez
CHANGELOG for Redis 1.1.90
  •  2009-09-10 in-memory specialized object encoding. (antirez)
  •  2009-09-17 maxmemory fixed in 64 systems for values > 4GB. (antirez)
  •  2009-10-07 multi-bulk protocol implemented. (antriez)
  •  2009-10-16 MSET and MSETNX commands implemented (antirez)
  •  2009-10-21 SRANDMEMBER added (antirez)
  •  2009-10-23 Fixed compilation in mac os x snow leopard when compiling a 32 bit binary.  (antirez)
  •  2009-10-23 New data type: Sorted sets and Z-commands (antirez)
  •  2009-10-26 Solaris fixed (Alan Harder)
  •  2009-10-29 Fixed Issue a number of open issues (antirez)
  •  2009-10-30 New persistence mode: append only file (antirez)
  •  2009-11-01 SORT STORE option (antirez)
  •  2009-11-03 redis-cli now accepts a -r (repeat) switch. (antirez)
  •  2009-11-04 masterauth option merged (Anthony Lauzon)
  •  2009-11-04 redis-test is now a better Redis citizen, testing everything against DB 9 and 10 and only if this DBs are empty. (antirez)
  •  2009-11-10 Implemented a much better lazy expiring algorithm for EXPIRE (antirez)
  •  2009-11-11 RPUSHLPOP (antirez from an idea of @ezmobius)
  •  2009-11-12 Merge git://github.com/ianxm/redis (Can't remmber what this implements, sorry)
  •  2009-11-17 multi-bulk reply support for redis-bench, LRANGE speed tests (antirez)
  •  2009-11-17 support for writev implemented. (Stefano Barbato)
  •  2009-11-19 debug mode (-D) in redis-bench (antirez)
  •  2009-11-21 SORT GET # implemented (antirez)
  •  2009-11-23 ae.c made modular, with support for epoll. (antirez)
  •  2009-11-26 background append log rebuilding (antirez)
  •  2009-11-28 Added support for kqueue. (Harish Mallipeddi)
  •  2009-11-29 SORT support for sorted sets (antirez, thanks to @tobi for the idea)
diff --git a/doc/ReplicationHowto.html b/doc/ReplicationHowto.html index e3e23499b..d0a6c6caa 100644 --- a/doc/ReplicationHowto.html +++ b/doc/ReplicationHowto.html @@ -26,12 +26,14 @@
-

Redis Replication Howto

General Information

Redis replication is a very simple to use and configure master-slave replication that allows slave Redis servers to be exact copies of master servers. The following are some very important facts about Redis replication:

-

How Redis replication works

In order to start the replication, or after the connection closes in order resynchronize with the master, the client connects to the master and issues the SYNC command.

The master starts a background saving, and at the same time starts to collect all the new commands received that had the effect to modify the dataset. When the background saving completed the master starts the transfer of the database file to the slave, that saves it on disk, and then load it in memory. At this point the master starts to send all the accumulated commands, and all the new commands received from clients, that had the effect of a dataset modification.

You can try it yourself via telnet. Connect to the Redis port while the server is doing some work and issue the SYNC command. You'll see a bulk transfer and then every command received by the master will be re-issued in the telnet session.

Slaves are able to automatically reconnect when the master <-> slave link goes down for some reason. If the master receives multiple concurrent slave synchronization requests it performs a single background saving in order to serve all them.

Configuration

To configure replication is trivial: just add the following line to the slave configuration file: + #sidebar RedisGuides +

Redis Replication Howto

General Information

Redis replication is a very simple to use and configure master-slave replication that allows slave Redis servers to be exact copies of master servers. The following are some very important facts about Redis replication:

+

How Redis replication works

In order to start the replication, or after the connection closes in order resynchronize with the master, the slave connects to the master and issues the SYNC command.

The master starts a background saving, and at the same time starts to collect all the new commands received that had the effect to modify the dataset. When the background saving completed the master starts the transfer of the database file to the slave, that saves it on disk, and then load it in memory. At this point the master starts to send all the accumulated commands, and all the new commands received from clients that had the effect of a dataset modification, to the slave, as a stream of commands, in the same format of the Redis protocol itself.

You can try it yourself via telnet. Connect to the Redis port while the server is doing some work and issue the SYNC command. You'll see a bulk transfer and then every command received by the master will be re-issued in the telnet session.

Slaves are able to automatically reconnect when the master <-> slave link goes down for some reason. If the master receives multiple concurrent slave synchronization requests it performs a single background saving in order to serve all them.

Configuration

To configure replication is trivial: just add the following line to the slave configuration file: 
 slaveof 192.168.1.1 6379
Of course you need to replace 192.168.1.1 6379 with your master ip address (or hostname) and port. +
diff --git a/doc/SaveCommand.html b/doc/SaveCommand.html index 4a8c830ad..5b703059a 100644 --- a/doc/SaveCommand.html +++ b/doc/SaveCommand.html @@ -27,9 +27,9 @@
#sidebar ControlCommandsSidebar

SAVE

-
Save the DB on disk. The server hangs while the saving is notcompleted, no connection is served in the meanwhile. An OK codeis returned when the DB was fully stored in disk.
+
Save the whole dataset on disk (this means that all the databases are saved, as well as keys with an EXPIRE set (the expire is preserved). The server hangs while the saving is notcompleted, no connection is served in the meanwhile. An OK codeis returned when the DB was fully stored in disk.
+
The background variant of this command is BGSAVE that is able to perform the saving in the background while the server continues serving other clients.

Return value

Status code reply -
diff --git a/doc/SmembersCommand.html b/doc/SmembersCommand.html index 97e30b3b7..a3ef124e0 100644 --- a/doc/SmembersCommand.html +++ b/doc/SmembersCommand.html @@ -27,9 +27,8 @@
#sidebar SetCommandsSidebar

SMEMBERS _key_

-Time complexity O(N)
Return all the members (elements) of the set value stored at key. Thisis just syntax glue for SINTERSECT.
+Time complexity O(N)
Return all the members (elements) of the set value stored at key. Thisis just syntax glue for SINTER.

Return value

Multi bulk reply -
diff --git a/doc/SortCommand.html b/doc/SortCommand.html index f89fd7c22..7ed3eb01f 100644 --- a/doc/SortCommand.html +++ b/doc/SortCommand.html @@ -16,7 +16,7 @@
-SortCommand: Contents
    Sorting by external keys
    Retrieving external keys
    Storing the result of a SORT operation
    Return value +SortCommand: Contents
    Sorting by external keys
    Retrieving external keys
    Storing the result of a SORT operation
    SORT and Hashes: BY and GET by hash field
    Return value

SortCommand

@@ -57,8 +57,12 @@ SORT mylist BY weight_* GET object_* GET # SORT mylist BY weight_* STORE resultkey
An interesting pattern using SORT ... STORE consists in associatingan EXPIRE timeout to the resulting key so that inapplications where the result of a sort operation can be cached forsome time other clients will use the cached list instead to call SORTfor every request. When the key will timeout an updated version ofthe cache can be created using SORT ... STORE again.
Note that implementing this pattern it is important to avoid that multipleclients will try to rebuild the cached version of the cacheat the same time, so some form of locking should be implemented(for instance using SETNX).
-

Return value

Multi bulk reply, specifically a list of sorted elements. - +

SORT and Hashes: BY and GET by hash field

+
It's possible to use BY and GET options against Hash fields using the following syntax:
+SORT mylist BY weight_*->fieldname
+SORT mylist GET object_*->fieldname
+
+
The two chars string -> is used in order to signal the name of the Hash field. The key is substituted as documented above with sort BY and GET against normal keys, and the Hash stored at the resulting key is accessed in order to retrieve the specified field.

Return value

Multi bulk reply, specifically a list of sorted elements.
diff --git a/doc/SortedSetCommandsSidebar.html b/doc/SortedSetCommandsSidebar.html index 7b722e951..8fb879d70 100644 --- a/doc/SortedSetCommandsSidebar.html +++ b/doc/SortedSetCommandsSidebar.html @@ -26,7 +26,7 @@
- == Sorted Set Commands ==

+ == Sorted Set Commands ==

diff --git a/doc/SponsorshipHistory.html b/doc/SponsorshipHistory.html index 97616db9e..107f9c8a0 100644 --- a/doc/SponsorshipHistory.html +++ b/doc/SponsorshipHistory.html @@ -26,7 +26,7 @@
-

Redis Sponsorship History

This is a list of companies that sponsorship Redis developments, with details about the sponsored features. Thanks for helping the project!.

If your company is considering a sponsorship please read the How to Sponsor page.

+

Redis Sponsorship History

Important notice: since 15 March 2010 I Joined VMware that is sponsoring all my work on Redis. Thank you to all the companies and people donating in the past. No further donations are accepted.

This is a list of companies that sponsorship Redis developments, with details about the sponsored features. Thanks for helping the project!.

Also thaks to the following people or organizations that donated to the Project:
diff --git a/doc/SponsorshipHowto.html b/doc/SponsorshipHowto.html deleted file mode 100644 index 2dc14fd5d..000000000 --- a/doc/SponsorshipHowto.html +++ /dev/null @@ -1,37 +0,0 @@ - - - - - - - -
- - - -
-
- -SponsorshipHowto: Contents
  Other donations -
- -

SponsorshipHowto

- -
- -
- -
- = How to sponsor my work on Redis =

I'm accepting sponsorships for Redis development, the idea is that a company using Redis and willing to donate some money can receive something back: visibility in the Redis site, and prioritization of features planned in the TODO list that are somewhat more important for this company compared to other features.

In the last year I spent 50% of my time working on Redis. At the same time Redis is released under the very liberal BSD license, this is very important for users as it prevents that in the future the project will be killed, but at the same time it's not possible to build a business model selling licenses like it happens for MySQL. The alternative is to run a consultancy company, but this means to use more time to work with customers than working to the Redis code base itself, or sponsorship, that I think is the best option currently to ensure fast development of the project.

So, if you are considering a donation, thank you! This is a set of simple rules I developed in order to make sure I'm fair with everybody willing to help the project:

  • 1. Every company can donate any amount of money, even 10$, in order to support Redis development.
  • 2. Every company donating an amount equal or greater than 1000$ will be featured in the home page for at least 6 months, and anyway for all the time the sponsored feature takes to reach a stable release of Redis.
  • 3. Every company donating at least 100$ will anyway be featured in the "Sponsors" page forever, this page is linked near to the logos of the current sponsors in the front page (the logos about point 2 of this list).
  • 4. A sponsoring company can donate for sponsorship of a feature already in the TODO list. If a feature not planned is needed we should first get in touch, discuss if this is a good idea, put it in the TODO list, and then the sponsorship can start, but I've to be genuinely convinced this feature will be good and of general interest ;)
  • 5. Not really a sponsorship/donation, but in rare case of a vertical, self-contained feature, I could develop it as a patch for the current stable Redis distribution for a "donation" proportional to the work needed to develop the feature, but in order to have the patch for the next release of Redis there will be to donate again for the porting work and so forth.
  • 6. Features for which I receive a good sponsorship (proportionally to the work required to implement the sponsored feature) are prioritized and will get developed faster than other features, possibly changing the development roadmap.
  • 7. To sponsor a specific feature is not a must, a company can just donate to the project as a whole.
-If you want to get in touch with me about this issues please drop me an email to my gmail account (username is antirez) or direct-message me @antirez on Twitter. Thanks in advance for the help!

Other donations

If you just feel like donating a small amount to Redis the simplest way is to use paypal, my paypal address is antirez@invece.org. Please specify in the donation if you don't like to have your name / company name published in the donations history (the amount will not be published anyway). -
- -
-
- - - diff --git a/doc/StringCommandsSidebar.html b/doc/StringCommandsSidebar.html index af7b5f6b6..369b0cfbf 100644 --- a/doc/StringCommandsSidebar.html +++ b/doc/StringCommandsSidebar.html @@ -26,7 +26,7 @@
- == String Commands ==

+ == String Commands ==

diff --git a/doc/TypeCommand.html b/doc/TypeCommand.html index 50c5bed91..45900422a 100644 --- a/doc/TypeCommand.html +++ b/doc/TypeCommand.html @@ -33,6 +33,8 @@ "string" if the key contains a String value "list" if the key contains a List value "set" if the key contains a Set value +"zset" if the key contains a Sorted Set value +"hash" if the key contains a Hash value

See also

diff --git a/doc/ZrangebyscoreCommand.html b/doc/ZrangebyscoreCommand.html index 6ffd87b38..429822512 100644 --- a/doc/ZrangebyscoreCommand.html +++ b/doc/ZrangebyscoreCommand.html @@ -16,7 +16,7 @@
-ZrangebyscoreCommand: Contents
  ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >
    Return value +ZrangebyscoreCommand: Contents
  ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >
  ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis >
    Return value

ZrangebyscoreCommand

@@ -27,11 +27,11 @@
#sidebar SortedSetCommandsSidebar

ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` (Redis >

1.1) = +

ZRANGEBYSCORE _key_ _min_ _max_ `[`LIMIT _offset_ _count_`]` `[`WITHSCORES`]` (Redis >

1.3.4) = Time complexity: O(log(N))+O(M) with N being the number of elements in the sorted set and M the number of elements returned by the command, so if M is constant (for instance you always ask for the first ten elements with LIMIT) you can consider it O(log(N))
Return the all the elements in the sorted set at key with a score between_min_ and max (including elements with score equal to min or max).
The elements having the same score are returned sorted lexicographically asASCII strings (this follows from a property of Redis sorted sets and does notinvolve further computation).
Using the optional LIMIT it's possible to get only a range of the matchingelements in an SQL-alike way. Note that if offset is large the commandsneeds to traverse the list for offset elements and this adds up to theO(M) figure.

Return value

Multi bulk reply, specifically a list of elements in the specified score range. -
diff --git a/doc/index.html b/doc/index.html index 85e49d4b0..2cf5d9a8b 100644 --- a/doc/index.html +++ b/doc/index.html @@ -16,7 +16,7 @@
-index: Contents
  Redis Documentation
  HOWTOs about selected features
  Hacking
  Videos +index: Contents
  HOWTOs about selected features
  Hacking
  Videos

index

@@ -26,10 +26,11 @@
-

Redis Documentation

Hello! The followings are pointers to different parts of the Redis Documentation.

-

HOWTOs about selected features

+ = Redis Documentation =

Russian TranslationHello! The followings are pointers to different parts of the Redis Documentation.

+

HOWTOs about selected features

Hacking

+

Videos

diff --git a/test/assets/default.conf b/tests/assets/default.conf similarity index 100% rename from test/assets/default.conf rename to tests/assets/default.conf diff --git a/test/support/redis.tcl b/tests/support/redis.tcl similarity index 100% rename from test/support/redis.tcl rename to tests/support/redis.tcl diff --git a/test/support/server.tcl b/tests/support/server.tcl similarity index 97% rename from test/support/server.tcl rename to tests/support/server.tcl index 7f95c4a9c..ead81e9ee 100644 --- a/test/support/server.tcl +++ b/tests/support/server.tcl @@ -31,7 +31,7 @@ proc kill_server config { } proc start_server {filename overrides {code undefined}} { - set data [split [exec cat "test/assets/$filename"] "\n"] + set data [split [exec cat "tests/assets/$filename"] "\n"] set config {} foreach line $data { if {[string length $line] > 0 && [string index $line 0] ne "#"} { @@ -67,7 +67,7 @@ proc start_server {filename overrides {code undefined}} { set stdout [format "%s/%s" [dict get $config "dir"] "stdout"] set stderr [format "%s/%s" [dict get $config "dir"] "stderr"] exec ./redis-server $config_file > $stdout 2> $stderr & - after 10 + after 500 # check that the server actually started if {[file size $stderr] > 0} { diff --git a/test/support/test.tcl b/tests/support/test.tcl similarity index 91% rename from test/support/test.tcl rename to tests/support/test.tcl index 742b98c9d..c695c82fa 100644 --- a/test/support/test.tcl +++ b/tests/support/test.tcl @@ -5,7 +5,7 @@ set ::testnum 0 proc test {name code okpattern} { incr ::testnum # if {$::testnum < $::first || $::testnum > $::last} return - puts -nonewline [format "#%03d %-70s " $::testnum $name] + puts -nonewline [format "#%03d %-68s " $::testnum $name] flush stdout set retval [uplevel 1 $code] if {$okpattern eq $retval || [string match $okpattern $retval]} { diff --git a/test/support/tmpfile.tcl b/tests/support/tmpfile.tcl similarity index 93% rename from test/support/tmpfile.tcl rename to tests/support/tmpfile.tcl index 7123c9104..809f58730 100644 --- a/test/support/tmpfile.tcl +++ b/tests/support/tmpfile.tcl @@ -1,5 +1,5 @@ set ::tmpcounter 0 -set ::tmproot "./test/tmp" +set ::tmproot "./tests/tmp" file mkdir $::tmproot # returns a dirname unique to this process to write to diff --git a/test/support/util.tcl b/tests/support/util.tcl similarity index 100% rename from test/support/util.tcl rename to tests/support/util.tcl diff --git a/test/test_helper.tcl b/tests/test_helper.tcl similarity index 79% rename from test/test_helper.tcl rename to tests/test_helper.tcl index 33c507f2e..cd8d65a1c 100644 --- a/test/test_helper.tcl +++ b/tests/test_helper.tcl @@ -3,11 +3,11 @@ # more information. set tcl_precision 17 -source test/support/redis.tcl -source test/support/server.tcl -source test/support/tmpfile.tcl -source test/support/test.tcl -source test/support/util.tcl +source tests/support/redis.tcl +source tests/support/server.tcl +source tests/support/tmpfile.tcl +source tests/support/test.tcl +source tests/support/util.tcl set ::host 127.0.0.1 set ::port 16379 @@ -15,7 +15,7 @@ set ::traceleaks 0 proc execute_tests name { set cur $::testnum - source "test/$name.tcl" + source "tests/$name.tcl" } # setup a list to hold a stack of clients. the proc "r" provides easy @@ -44,8 +44,8 @@ proc main {} { } # clean up tmp - exec rm -rf {*}[glob test/tmp/redis.conf.*] - exec rm -rf {*}[glob test/tmp/server.*] + exec rm -rf {*}[glob tests/tmp/redis.conf.*] + exec rm -rf {*}[glob tests/tmp/server.*] } main diff --git a/test/tmp/.gitignore b/tests/tmp/.gitignore similarity index 100% rename from test/tmp/.gitignore rename to tests/tmp/.gitignore diff --git a/test/unit/auth.tcl b/tests/unit/auth.tcl similarity index 100% rename from test/unit/auth.tcl rename to tests/unit/auth.tcl diff --git a/test/unit/basic.tcl b/tests/unit/basic.tcl similarity index 100% rename from test/unit/basic.tcl rename to tests/unit/basic.tcl diff --git a/test/unit/expire.tcl b/tests/unit/expire.tcl similarity index 100% rename from test/unit/expire.tcl rename to tests/unit/expire.tcl diff --git a/test/unit/other.tcl b/tests/unit/other.tcl similarity index 100% rename from test/unit/other.tcl rename to tests/unit/other.tcl diff --git a/test/unit/protocol.tcl b/tests/unit/protocol.tcl similarity index 100% rename from test/unit/protocol.tcl rename to tests/unit/protocol.tcl diff --git a/test/unit/sort.tcl b/tests/unit/sort.tcl similarity index 100% rename from test/unit/sort.tcl rename to tests/unit/sort.tcl diff --git a/test/unit/type/hash.tcl b/tests/unit/type/hash.tcl similarity index 100% rename from test/unit/type/hash.tcl rename to tests/unit/type/hash.tcl diff --git a/test/unit/type/list.tcl b/tests/unit/type/list.tcl similarity index 100% rename from test/unit/type/list.tcl rename to tests/unit/type/list.tcl diff --git a/test/unit/type/set.tcl b/tests/unit/type/set.tcl similarity index 100% rename from test/unit/type/set.tcl rename to tests/unit/type/set.tcl diff --git a/test/unit/type/zset.tcl b/tests/unit/type/zset.tcl similarity index 100% rename from test/unit/type/zset.tcl rename to tests/unit/type/zset.tcl -- GitLab