<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Find whether to send the query to the master, the slave or the last used MySQL server</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.mysqlnd-ms-match-wild.html">mysqlnd_ms_match_wild</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mysqlnd-ms-set-qos.html">mysqlnd_ms_set_qos</a></div> <div class="up"><a href="ref.mysqlnd-ms.html">Mysqlnd_ms Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="function.mysqlnd-ms-query-is-select" class="refentry"> <div class="refnamediv"> <h1 class="refname">mysqlnd_ms_query_is_select</h1> <p class="verinfo">(PECL mysqlnd_ms >= 1.0.0)</p><p class="refpurpose"><span class="refname">mysqlnd_ms_query_is_select</span> — <span class="dc-title">Find whether to send the query to the master, the slave or the last used MySQL server</span></p> </div> <div class="refsect1 description" id="refsect1-function.mysqlnd-ms-query-is-select-description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">int</span> <span class="methodname"><strong>mysqlnd_ms_query_is_select</strong></span> ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$query</code></span> )</div> <p class="para rdfs-comment"> Finds whether to send the query to the master, the slave or the last used MySQL server. </p> <p class="para"> The plugins built-in read/write split mechanism will be used to analyze the query string to make a recommendation where to send the query. The built-in read/write split mechanism is very basic and simple. The plugin will recommend sending all queries to the MySQL replication master server but those which begin with <em>SELECT</em>, or begin with a SQL hint which enforces sending the query to a slave server. Due to the basic but fast algorithm the plugin may propose to run some read-only statements such as <em>SHOW TABLES</em> on the replication master. </p> </div> <div class="refsect1 parameters" id="refsect1-function.mysqlnd-ms-query-is-select-parameters"> <h3 class="title">Parameters</h3> <dl> <dt> <span class="term"><em><code class="parameter">query</code></em></span> <dd> <p class="para"> Query string to test. </p> </dd> </dt> </dl> </div> <div class="refsect1 returnvalues" id="refsect1-function.mysqlnd-ms-query-is-select-returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> A return value of <strong><code>MYSQLND_MS_QUERY_USE_MASTER</code></strong> indicates that the query should be send to the MySQL replication master server. The function returns a value of <strong><code>MYSQLND_MS_QUERY_USE_SLAVE</code></strong> if the query can be run on a slave because it is considered read-only. A value of <strong><code>MYSQLND_MS_QUERY_USE_LAST_USED</code></strong> is returned to recommend running the query on the last used server. This can either be a MySQL replication master server or a MySQL replication slave server. </p> <p class="para"> If read write splitting has been disabled by setting <em>mysqlnd_ms.disable_rw_split</em>, the function will always return <strong><code>MYSQLND_MS_QUERY_USE_MASTER</code></strong> or <strong><code>MYSQLND_MS_QUERY_USE_LAST_USED</code></strong>. </p> </div> <div class="refsect1 examples" id="refsect1-function.mysqlnd-ms-query-is-select-examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example" id="example-1842"> <p><strong>Example #1 <span class="function"><strong>mysqlnd_ms_query_is_select()</strong></span> example</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">is_select</span><span style="color: #007700">(</span><span style="color: #0000BB">$query</span><span style="color: #007700">)<br />{<br /> switch (</span><span style="color: #0000BB">mysqlnd_ms_query_is_select</span><span style="color: #007700">(</span><span style="color: #0000BB">$query</span><span style="color: #007700">))<br /> {<br /> case </span><span style="color: #0000BB">MYSQLND_MS_QUERY_USE_MASTER</span><span style="color: #007700">:<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"'%s' should be run on the master.\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> break;<br /> case </span><span style="color: #0000BB">MYSQLND_MS_QUERY_USE_SLAVE</span><span style="color: #007700">:<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"'%s' should be run on a slave.\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> break;<br /> case </span><span style="color: #0000BB">MYSQLND_MS_QUERY_USE_LAST_USED</span><span style="color: #007700">:<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"'%s' should be run on the server that has run the previous query\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> break;<br /> default:<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"No suggestion where to run the '%s', fallback to master recommended\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> break;<br /> }<br />}<br /><br /></span><span style="color: #0000BB">is_select</span><span style="color: #007700">(</span><span style="color: #DD0000">"INSERT INTO test(id) VALUES (1)"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">is_select</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT 1 FROM DUAL"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">is_select</span><span style="color: #007700">(</span><span style="color: #DD0000">"/*" </span><span style="color: #007700">. </span><span style="color: #0000BB">MYSQLND_MS_LAST_USED_SWITCH </span><span style="color: #007700">. </span><span style="color: #DD0000">"*/SELECT 2 FROM DUAL"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> <div class="example-contents"><p>The above example will output:</p></div> <div class="example-contents screen"> <div class="cdata"><pre> INSERT INTO test(id) VALUES (1) should be run on the master. SELECT 1 FROM DUAL should be run on a slave. /*ms=last_used*/SELECT 2 FROM DUAL should be run on the server that has run the previous query </pre></div> </div> </div> </p> </div> <div class="refsect1 seealso" id="refsect1-function.mysqlnd-ms-query-is-select-seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"> <a href="mysqlnd-ms.constants.html" class="link">Predefined Constants</a> </li> <li class="member"> <a href="mysqlnd-ms.plugin-ini-json.html#ini.mysqlnd-ms-plugin-config-v2.filter-user" class="link"><em>user</em></a> filter </li> </ul> <ul class="simplelist"> <li class="member"> <a href="mysqlnd-ms.configuration.html" class="link">Runtime configuration</a> </li> <li class="member"> <a href="mysqlnd-ms.configuration.html#ini.mysqlnd-ms.disable-rw-split" class="link">mysqlnd_ms.disable_rw_split</a> </li> <li class="member"> <a href="mysqlnd-ms.configuration.html#ini.mysqlnd-ms.enable" class="link">mysqlnd_ms.enable</a> </li> </ul> </p> </div> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.mysqlnd-ms-match-wild.html">mysqlnd_ms_match_wild</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mysqlnd-ms-set-qos.html">mysqlnd_ms_set_qos</a></div> <div class="up"><a href="ref.mysqlnd-ms.html">Mysqlnd_ms Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>