Commit 73287b2b authored by antirez's avatar antirez
Browse files

buliding of release.h moved into an external script. Avoided recompialtion of...

buliding of release.h moved into an external script. Avoided recompialtion of redis.c if git sha1 is the same as the previous one
parent 5436146c
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>RpoplpushCommand: Contents</b><br>&nbsp;&nbsp;<a href="#RPOPLPUSH _srckey_ _dstkey_ (Redis &gt;">RPOPLPUSH _srckey_ _dstkey_ (Redis &gt;</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Programming patterns: safe queues">Programming patterns: safe queues</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Programming patterns: server-side O(N) list traversal">Programming patterns: server-side O(N) list traversal</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">RpoplpushCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="ListCommandsSidebar.html">ListCommandsSidebar</a><h1><a name="RPOPLPUSH _srckey_ _dstkey_ (Redis &gt;">RPOPLPUSH _srckey_ _dstkey_ (Redis &gt;</a></h1> 1.1) =
<i>Time complexity: O(1)</i><blockquote>Atomically return and remove the last (tail) element of the <i>srckey</i> list,and push the element as the first (head) element of the <i>dstkey</i> list. Forexample if the source list contains the elements &quot;a&quot;,&quot;b&quot;,&quot;c&quot; and thedestination list contains the elements &quot;foo&quot;,&quot;bar&quot; after an RPOPLPUSH commandthe content of the two lists will be &quot;a&quot;,&quot;b&quot; and &quot;c&quot;,&quot;foo&quot;,&quot;bar&quot;.</blockquote>
<blockquote>If the <i>key</i> does not exist or the list is already empty the specialvalue 'nil' is returned. If the <i>srckey</i> and <i>dstkey</i> are the same theoperation is equivalent to removing the last element from the list and pusingit as first element of the list, so it's a &quot;list rotation&quot; command.</blockquote>
<h2><a name="Programming patterns: safe queues">Programming patterns: safe queues</a></h2><blockquote>Redis lists are often used as queues in order to exchange messages betweendifferent programs. A program can add a message performing an <a href="RpushCommand.html">LPUSH</a> operationagainst a Redis list (we call this program a Producer), while another program(that we call Consumer) can process the messages performing an <a href="LpopCommand.html">RPOP</a> commandin order to start reading the messages from the oldest.</blockquote>
<blockquote>Unfortunately if a Consumer crashes just after an <a href="LpopCommand.html">RPOP</a> operation the messagegets lost. RPOPLPUSH solves this problem since the returned message isadded to another &quot;backup&quot; list. The Consumer can later remove the messagefrom the backup list using the <a href="LremCommand.html">LREM</a> command when the message was correctlyprocessed.</blockquote>
<blockquote>Another process, called Helper, can monitor the &quot;backup&quot; list to check fortimed out entries to repush against the main queue.</blockquote>
<h2><a name="Programming patterns: server-side O(N) list traversal">Programming patterns: server-side O(N) list traversal</a></h2><blockquote>Using RPOPPUSH with the same source and destination key a process canvisit all the elements of an N-elements List in O(N) without to transferthe full list from the server to the client in a single <a href="LrangeCommand.html">LRANGE</a> operation.Note that a process can traverse the list even while other processesare actively RPUSHing against the list, and still no element will be skipped.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Bulk reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>RpushCommand: Contents</b><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#RPUSH _key_ _string_">RPUSH _key_ _string_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#LPUSH _key_ _string_">LPUSH _key_ _string_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">RpushCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="ListCommandsSidebar.html">ListCommandsSidebar</a><h3><a name="RPUSH _key_ _string_">RPUSH _key_ _string_</a></h3>
<h3><a name="LPUSH _key_ _string_">LPUSH _key_ _string_</a></h3>
<i>Time complexity: O(1)</i><blockquote>Add the <i>string</i> value to the head (RPUSH) or tail (LPUSH) of the liststored at <i>key</i>. If the key does not exist an empty list is created just beforethe append operation. If the key exists but is not a List an erroris returned.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SaddCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SADD _key_ _member_">SADD _key_ _member_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SaddCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SADD _key_ _member_">SADD _key_ _member_</a></h1>
<i>Time complexity O(1)</i><blockquote>Add the specified <i>member</i> to the set value stored at <i>key</i>. If <i>member</i>is already a member of the set no operation is performed. If <i>key</i>does not exist a new set with the specified <i>member</i> as sole member iscreated. If the key exists but does not hold a set value an error isreturned.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
1 if the new element was added
0 if the element was already a member of the set
</pre>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SaveCommand: Contents</b><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#SAVE">SAVE</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SaveCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="ControlCommandsSidebar.html">ControlCommandsSidebar</a><h3><a name="SAVE">SAVE</a></h3>
<blockquote>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.</blockquote>
<blockquote>The background variant of this command is <a href="BgsaveCommand.html">BGSAVE</a> that is able to perform the saving in the background while the server continues serving other clients.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>ScardCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SCARD _key_">SCARD _key_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">ScardCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SCARD _key_">SCARD _key_</a></h1>
<i>Time complexity O(1)</i><blockquote>Return the set cardinality (number of elements). If the <i>key</i> does notexist 0 is returned, like for empty sets.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
the cardinality (number of elements) of the set as an integer.
</pre>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SdiffCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SDIFF _key1_ _key2_ ... _keyN_">SDIFF _key1_ _key2_ ... _keyN_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SdiffCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SDIFF _key1_ _key2_ ... _keyN_">SDIFF _key1_ _key2_ ... _keyN_</a></h1>
<i>Time complexity O(N) with N being the total number of elements of all the sets</i><blockquote>Return the members of a set resulting from the difference between the firstset provided and all the successive sets. Example:</blockquote>
<pre class="codeblock python" name="code">
key1 = x,a,b,c
key2 = c
key3 = a,d
SDIFF key1,key2,key3 =&gt; x,b
</pre><blockquote>Non existing keys are considered like empty sets.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>, specifically the list of common elements.
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SdiffstoreCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SDIFFSTORE _dstkey_ _key1_ _key2_ ... _keyN_">SDIFFSTORE _dstkey_ _key1_ _key2_ ... _keyN_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SdiffstoreCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SDIFFSTORE _dstkey_ _key1_ _key2_ ... _keyN_">SDIFFSTORE _dstkey_ _key1_ _key2_ ... _keyN_</a></h1>
<i>Time complexity O(N) where N is the total number of elements in all the provided sets</i><blockquote>This command works exactly like SDIFF but instead of being returned the resulting set is stored in <i>dstkey</i>.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SelectCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SELECT _index_">SELECT _index_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SelectCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="GenericCommandsSidebar.html">GenericCommandsSidebar</a><h1><a name="SELECT _index_">SELECT _index_</a></h1>
<blockquote>Select the DB with having the specified zero-based numeric index.For default every new client connection is automatically selectedto DB 0.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SetCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SET _key_ _value_">SET _key_ _value_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SetCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="StringCommandsSidebar.html">StringCommandsSidebar</a><h1><a name="SET _key_ _value_">SET _key_ _value_</a></h1>
<i>Time complexity: O(1)</i><blockquote>Set the string <i>value</i> as value of the <i>key</i>.The string can't be longer than 1073741824 bytes (1 GB).</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SetCommandsSidebar: Contents</b>
</div>
<h1 class="wikiname">SetCommandsSidebar</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;== Set Commands ==<br/><br/><ul><li> <a href="SaddCommand.html">SADD</a></li><li> <a href="SremCommand.html">SREM</a></li><li> <a href="SpopCommand.html">SPOP</a></li><li> <a href="SmoveCommand.html">SMOVE</a></li><li> <a href="ScardCommand.html">SCARD</a></li><li> <a href="SismemberCommand.html">SISMEMBER</a></li><li> <a href="SinterCommand.html">SINTER</a></li><li> <a href="SinterstoreCommand.html">SINTERSTORE</a></li><li> <a href="SunionCommand.html">SUNION</a></li><li> <a href="SunionstoreCommand.html">SUNIONSTORE</a></li><li> <a href="SdiffCommand.html">SDIFF</a></li><li> <a href="SdiffstoreCommand.html">SDIFFSTORE</a></li><li> <a href="SmembersCommand.html">SMEMBERS</a></li><li> <a href="SrandmemberCommand.html">SRANDMEMBER</a></li><li> <a href="SortCommand.html">SORT</a></li></ul>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SetnxCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SETNX _key_ _value_">SETNX _key_ _value_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Design pattern: Implementing locking with SETNX">Design pattern: Implementing locking with SETNX</a><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Handling deadlocks">Handling deadlocks</a>
</div>
<h1 class="wikiname">SetnxCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="StringCommandsSidebar.html">StringCommandsSidebar</a><h1><a name="SETNX _key_ _value_">SETNX _key_ _value_</a></h1>
<i>Time complexity: O(1)</i><blockquote>SETNX works exactly like <a href="SetCommand.html">SET</a> with the only difference thatif the key already exists no operation is performed.SETNX actually means &quot;SET if Not eXists&quot;.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
1 if the key was set
0 if the key was not set
</pre><h2><a name="Design pattern: Implementing locking with SETNX">Design pattern: Implementing locking with SETNX</a></h2><blockquote>SETNX can also be seen as a locking primitive. For instance to acquirethe lock of the key <b>foo</b>, the client could try the following:</blockquote>
<pre class="codeblock python python" name="code">
SETNX lock.foo &lt;current UNIX time + lock timeout + 1&gt;
</pre><blockquote>If SETNX returns 1 the client acquired the lock, setting the <b>lock.foo</b>key to the UNIX time at witch the lock should no longer be considered valid.The client will later use <b>DEL lock.foo</b> in order to release the lock.</blockquote>
<blockquote>If SETNX returns 0 the key is already locked by some other client. We caneither return to the caller if it's a non blocking lock, or enter aloop retrying to hold the lock until we succeed or some kind of timeoutexpires.</blockquote>
<h3><a name="Handling deadlocks">Handling deadlocks</a></h3><blockquote>In the above locking algorithm there is a problem: what happens if a clientfails, crashes, or is otherwise not able to release the lock?It's possible to detect this condition because the lock key contains aUNIX timestamp. If such a timestamp is &lt;= the current Unix time the lockis no longer valid.</blockquote>
<blockquote>When this happens we can't just call DEL against the key to remove the lockand then try to issue a SETNX, as there is a race condition here, whenmultiple clients detected an expired lock and are trying to release it.</blockquote>
<ul><li> C1 and C2 read lock.foo to check the timestamp, because SETNX returned 0 to both C1 and C2, as the lock is still hold by C3 that crashed after holding the lock.</li><li> C1 sends DEL lock.foo</li><li> C1 sends SETNX =&gt; success!</li><li> C2 sends DEL lock.foo</li><li> C2 sends SETNX =&gt; success!</li><li> ERROR: both C1 and C2 acquired the lock because of the race condition.</li></ul>
<blockquote>Fortunately it's possible to avoid this issue using the following algorithm.Let's see how C4, our sane client, uses the good algorithm:</blockquote>
<ul><li> C4 sends SETNX lock.foo in order to acquire the lock</li><li> The crashed C3 client still holds it, so Redis will reply with 0 to C4.</li><li> C4 GET lock.foo to check if the lock expired. If not it will sleep one second (for instance) and retry from the start.</li><li> If instead the lock is expired because the UNIX time at lock.foo is older than the current UNIX time, C4 tries to perform GETSET lock.foo &lt;current unix timestamp + lock timeout + 1&gt;</li><li> Thanks to the <a href="GetsetCommand.html">GETSET</a> command semantic C4 can check if the old value stored at key is still an expired timestamp. If so we acquired the lock!</li><li> Otherwise if another client, for instance C5, was faster than C4 and acquired the lock with the GETSET operation, C4 GETSET operation will return a non expired timestamp. C4 will simply restart from the first step. Note that even if C4 set the key a bit a few seconds in the future this is not a problem.</li></ul>
IMPORTANT NOTE: In order to make this locking algorithm more robust, a client holding a lock should always check the timeout didn't expired before to unlock the key with DEL because client failures can be complex, not just crashing but also blocking a lot of time against some operation and trying to issue DEL after a lot of time (when the LOCK is already hold by some other client).
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>Sets: Contents</b><br>&nbsp;&nbsp;<a href="#Redis Set Type">Redis Set Type</a><br>&nbsp;&nbsp;<a href="#Implementation details">Implementation details</a>
</div>
<h1 class="wikiname">Sets</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="Redis Set Type">Redis Set Type</a></h1>Redis Sets are unordered collections of <a href="Strings.html">Redis Strings</a>. It's possible to add, remove, and test for existence of members in O(1).<br/><br/>Redis Sets have the desirable property of not allowing repeated members. Adding the same element multiple times will result in a set having a single copy of this element. Practically speaking this means that adding an members does not require a &quot;check if exists then add&quot; operation.<br/><br/>Commands operating on sets try to make a good use of the return value in order to signal the application about previous existence of members. For instance the <a href="SaddCommand.html">SADD</a> command will return 1 if the element added was not already a member of the set, otherwise will return 0.<br/><br/>The max number of members in a set is 232-1 (4294967295, more than 4 billion of members per set).<br/><br/>Redis Sets support a wide range of operations, like union, intersection, difference. Intersection is optimized in order to perform the smallest number of lookups. For instance if you try to intersect a 10000 members set with a 2 members set Redis will iterate the 2 members set testing for members existence in the other set, performing 2 lookups instead of 10000.<h1><a name="Implementation details">Implementation details</a></h1>Redis Sets are implemented using hash tables, so adding, removing and testing for members is O(1) in the average. The hash table will automatically resize when new elements are added or removed into a Set.<br/><br/>The hash table resizing is a blocking operation performed synchronously so working with huge sets (consisting of many millions of elements) care should be taken when mass-inserting a very big amount of elements in a Set while other clients are querying Redis at high speed.<br/><br/>It is possible that in the near future Redis will switch to skip lists (already used in sorted sets) in order to avoid such a problem.
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>ShutdownCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SHUTDOWN">SHUTDOWN</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">ShutdownCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="ControlCommandsSidebar.html">ControlCommandsSidebar</a><h1><a name="SHUTDOWN">SHUTDOWN</a></h1>
<blockquote>Stop all the clients, save the DB, then quit the server. This commandsmakes sure that the DB is switched off without the lost of any data.This is not guaranteed if the client uses simply &quot;SAVE&quot; and then&quot;QUIT&quot; because other clients may alter the DB data between the twocommands.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a> on error. On success nothing is returned since the server quits and the connection is closed.
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SideBar: Contents</b>
</div>
<h1 class="wikiname">SideBar</h1>
<div class="summary">
</div>
<div class="narrow">
DRAFT<br/><br/><ul><li> <a href="Features.html">Features</a></li><li> <a href="QuickStart.html">Quick Start</a></li><li> <a href="DataTypes.html">Data Types</a></li><li> <a href="SupportedLanguages.html">Supported Languages</a></li><li> <a href="ObjectHashMappers.html">Object Hash Mappers</a></li><li> <a href="ProgrammingExamples.html">Programming Examples</a></li><li> <a href="RoadMap.html">Road Map</a></li><li> <a href="Speed.html">Speed</a></li><li> <a href="FromSqlToDataStructures.html">FromSqlToDataStructures</a></li></ul><blockquote></blockquote>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SinterCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SINTER _key1_ _key2_ ... _keyN_">SINTER _key1_ _key2_ ... _keyN_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SinterCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SINTER _key1_ _key2_ ... _keyN_">SINTER _key1_ _key2_ ... _keyN_</a></h1>
<i>Time complexity O(NM) worst case where N is the cardinality of the smallest set and M the number of sets</i><blockquote>Return the members of a set resulting from the intersection of all thesets hold at the specified keys. Like in LRANGE the result is sent tothe client as a multi-bulk reply (see the protocol specification formore information). If just a single key is specified, then this commandproduces the same result as SMEMBERS. Actually SMEMBERS is just syntaxsugar for SINTERSECT.</blockquote>
<blockquote>Non existing keys are considered like empty sets, so if one of the keys ismissing an empty set is returned (since the intersection with an emptyset always is an empty set).</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>, specifically the list of common elements.
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SinterstoreCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SINTERSTORE _dstkey_ _key1_ _key2_ ... _keyN_">SINTERSTORE _dstkey_ _key1_ _key2_ ... _keyN_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SinterstoreCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SINTERSTORE _dstkey_ _key1_ _key2_ ... _keyN_">SINTERSTORE _dstkey_ _key1_ _key2_ ... _keyN_</a></h1>
<i>Time complexity O(NM) worst case where N is the cardinality of the smallest set and M the number of sets</i><blockquote>This commnad works exactly like SINTER but instead of being returned the resulting set is sotred as <i>dstkey</i>.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SismemberCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SISMEMBER _key_ _member_">SISMEMBER _key_ _member_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SismemberCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SISMEMBER _key_ _member_">SISMEMBER _key_ _member_</a></h1>
<i>Time complexity O(1)</i><blockquote>Return 1 if <i>member</i> is a member of the set stored at <i>key</i>, otherwise0 is returned.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
1 if the element is a member of the set
0 if the element is not a member of the set OR if the key does not exist
</pre>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SlaveofCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SLAVEOF _host_ _port_">SLAVEOF _host_ _port_</a><br>&nbsp;&nbsp;<a href="#SLAVEOF no one">SLAVEOF no one</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SlaveofCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="ControlCommandsSidebar.html">ControlCommandsSidebar</a><h1><a name="SLAVEOF _host_ _port_">SLAVEOF _host_ _port_</a></h1>
<h1><a name="SLAVEOF no one">SLAVEOF no one</a></h1><blockquote>The SLAVEOF command can change the replication settings of a slave on the fly.If a Redis server is arleady acting as slave, the command <code name="code" class="python">SLAVEOF NO ONE</code>will turn off the replicaiton turning the Redis server into a MASTER.In the proper form <code name="code" class="python">SLAVEOF hostname port</code> will make the server a slave of thespecific server listening at the specified hostname and port.</blockquote>
<blockquote>If a server is already a slave of some master, <code name="code" class="python">SLAVEOF hostname port</code> willstop the replication against the old server and start the synchrnonizationagainst the new one discarding the old dataset.</blockquote>
<blockquote>The form <code name="code" class="python">SLAVEOF no one</code> will stop replication turning the server into aMASTER but will not discard the replication. So if the old master stop workingit is possible to turn the slave into a master and set the application touse the new master in read/write. Later when the other Redis server will befixed it can be configured in order to work as slave.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Status code reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SmembersCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SMEMBERS _key_">SMEMBERS _key_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SmembersCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SMEMBERS _key_">SMEMBERS _key_</a></h1>
<i>Time complexity O(N)</i><blockquote>Return all the members (elements) of the set value stored at <i>key</i>. Thisis just syntax glue for <a href="SintersectCommand.html">SINTER</a>.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Multi bulk reply</a>
</div>
</div>
</div>
</body>
</html>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<link type="text/css" rel="stylesheet" href="style.css" />
</head>
<body>
<div id="page">
<div id='header'>
<a href="index.html">
<img style="border:none" alt="Redis Documentation" src="redis.png">
</a>
</div>
<div id="pagecontent">
<div class="index">
<!-- This is a (PRE) block. Make sure it's left aligned or your toc title will be off. -->
<b>SmoveCommand: Contents</b><br>&nbsp;&nbsp;<a href="#SMOVE _srckey_ _dstkey_ _member_">SMOVE _srckey_ _dstkey_ _member_</a><br>&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Return value">Return value</a>
</div>
<h1 class="wikiname">SmoveCommand</h1>
<div class="summary">
</div>
<div class="narrow">
&iuml;&raquo;&iquest;#sidebar <a href="SetCommandsSidebar.html">SetCommandsSidebar</a><h1><a name="SMOVE _srckey_ _dstkey_ _member_">SMOVE _srckey_ _dstkey_ _member_</a></h1>
<i>Time complexity O(1)</i><blockquote>Move the specifided <i>member</i> from the set at <i>srckey</i> to the set at <i>dstkey</i>.This operation is atomic, in every given moment the element will appear tobe in the source or destination set for accessing clients.</blockquote>
<blockquote>If the source set does not exist or does not contain the specified elementno operation is performed and zero is returned, otherwise the element isremoved from the source set and added to the destination set. On successone is returned, even if the element was already present in the destinationset.</blockquote>
<blockquote>An error is raised if the source or destination keys contain a non Set value.</blockquote>
<h2><a name="Return value">Return value</a></h2><a href="ReplyTypes.html">Integer reply</a>, specifically:<br/><br/><pre class="codeblock python" name="code">
1 if the element was moved
0 if the element was not found on the first set and no operation was performed
</pre>
</div>
</div>
</div>
</body>
</html>
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment