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| author | Horus3 | 2014-02-24 16:42:14 +0100 |
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| committer | Horus3 | 2014-02-24 16:42:14 +0100 |
| commit | 06f945f27840b53e57795dadbc38e76f7e11ab1c (patch) | |
| tree | 689d5c7f4ffa15460c7e90f47c6a7dd59ce4e8bd /zend/documentation/manual/core/en/performance.database.html | |
| download | random-06f945f27840b53e57795dadbc38e76f7e11ab1c.tar.gz | |
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| -rw-r--r-- | zend/documentation/manual/core/en/performance.database.html | 202 |
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diff --git a/zend/documentation/manual/core/en/performance.database.html b/zend/documentation/manual/core/en/performance.database.html new file mode 100644 index 0000000..a4b0ea8 --- /dev/null +++ b/zend/documentation/manual/core/en/performance.database.html @@ -0,0 +1,202 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> + <meta http-equiv="content-type" content="text/html; charset=UTF-8"/> + <title>Zend_Db Performance - Zend Framework Manual</title> + +</head> +<body> +<table width="100%"> + <tr valign="top"> + <td width="85%"> + <table width="100%"> + <tr> + <td width="25%" style="text-align: left;"> + <a href="performance.classloading.html">Class Loading</a> + </td> + + <td width="50%" style="text-align: center;"> + <div class="up"><span class="up"><a href="performance.html">Zend Gdata Performance Guide</a></span><br /> + <span class="home"><a href="manual.html">Programmer's Reference Guide</a></span></div> + </td> + + <td width="25%" style="text-align: right;"> + <div class="next" style="text-align: right; float: right;"><a href="performance.localization.html">Internationalization (i18n) and Localization (l10n)</a></div> + </td> + </tr> + </table> +<hr /> +<div id="performance.database" class="section"><div class="info"><h1 class="title">Zend_Db Performance</h1></div> + + + <p class="para"> + <span class="classname">Zend_Db</span> is a database abstraction layer, and is intended to + provide a common <acronym class="acronym">API</acronym> for <acronym class="acronym">SQL</acronym> operations. + <span class="classname">Zend_Db_Table</span> is a + Table Data Gateway, intended to abstract common table-level database + operations. Due to their abstract nature and the "magic" they do under + the hood to perform their operations, they can sometimes introduce + performance overhead. + </p> + + <div class="section" id="performance.database.tableMetadata" name="performance.database.tableMetadata"><div class="info"><h1 class="title">How can I reduce overhead introduced by Zend_Db_Table for + retrieving table metadata?</h1></div> + + + <p class="para"> + In order to keep usage as simple as possible, and also to support + constantly changing schemas during development, + <span class="classname">Zend_Db_Table</span> does some magic under the hood: on + first use, it fetches the table schema and stores it within object + members. This operation is typically expensive, regardless of the + database -- which can contribute to bottlenecks in production. + </p> + + <p class="para"> + Fortunately, there are techniques for improving the situation. + </p> + + <div class="section" id="performance.database.tableMetadata.cache" name="performance.database.tableMetadata.cache"><div class="info"><h1 class="title">Use the metadata cache</h1></div> + + + <p class="para"> + <span class="classname">Zend_Db_Table</span> can optionally utilize + <span class="classname">Zend_Cache</span> to cache table metadata. This is + typically faster to access and less expensive than fetching the + metadata from the database itself. + </p> + + <p class="para"> + The <a href="" class="link"><span class="classname">Zend_Db_Table + </span> documentation includes information on metadata caching</a>. + </p> + </div> + + <div class="section" id="performance.database.tableMetadata.hardcoding" name="performance.database.tableMetadata.hardcoding"><div class="info"><h1 class="title">Hardcode your metadata in the table definition</h1></div> + + + <p class="para"> + As of 1.7.0, <span class="classname">Zend_Db_Table</span> also provides <a href="" class="link">support + for hardcoding metadata in the table definition</a>. This is + an advanced use case, and should only be used when you know the + table schema is unlikely to change, or that you're able to keep + the definitions up-to-date. + </p> + </div> + </div> + + <div class="section" id="performance.database.select" name="performance.database.select"><div class="info"><h1 class="title"> + SQL generated with Zend_Db_Select s not hitting my indexes; how can I make it better? + </h1></div> + + + <p class="para"> + <span class="classname">Zend_Db_Select</span> is relatively good at its job. However, + if you are performing complex queries requiring joins or + sub-selects, it can often be fairly naive. + </p> + + <div class="section" id="performance.database.select.writeyourown" name="performance.database.select.writeyourown"><div class="info"><h1 class="title">Write your own tuned SQL</h1></div> + + + <p class="para"> + The only real answer is to write your own <acronym class="acronym">SQL</acronym>; + <span class="classname">Zend_Db</span> does not require the usage of + <span class="classname">Zend_Db_Select</span>, so providing your own, tuned + <acronym class="acronym">SQL</acronym> select statements is a perfectly legitimate approach, + </p> + + <p class="para"> + Run <b><tt>EXPLAIN</tt></b> on your queries, and test a variety of + approaches until you can reliably hit your indices in the most + performant way -- and then hardcode the <acronym class="acronym">SQL</acronym> as a class property + or constant. + </p> + + <p class="para"> + If the <acronym class="acronym">SQL</acronym> requires variable arguments, provide placeholders in + the <acronym class="acronym">SQL</acronym>, and utilize a combination of + <span class="methodname">vsprintf()</span> and <span class="methodname">array_map()</span> to + inject the values into the <acronym class="acronym">SQL</acronym>: + </p> + + <div class="programlisting php"><div class="phpcode"><div class="php" style="font-family: monospace;"><ol><li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"><span style="color: #808080; font-style: italic;">// $adapter is the DB adapter. In Zend_Db_Table, retrieve</span></div></li> +<li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"><span style="color: #808080; font-style: italic;">// it using $this->getAdapter().</span></div></li> +<li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"><span style="color: #0000ff;">$sql</span> = <a href="http://www.php.net/vsprintf"><span style="color: #000066;">vsprintf</span></a><span style="color: #66cc66;">(</span></div></li> +<li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"> self::<span style="color: #006600;">SELECT_FOO</span>,</div></li> +<li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"> <a href="http://www.php.net/array_map"><span style="color: #000066;">array_map</span></a><span style="color: #66cc66;">(</span><a href="http://www.php.net/array"><span style="color: #000066;">array</span></a><span style="color: #66cc66;">(</span><span style="color: #0000ff;">$adapter</span>, <span style="color: #ff0000;">'quoteInto'</span><span style="color: #66cc66;">)</span>, <span style="color: #0000ff;">$values</span><span style="color: #66cc66;">)</span></div></li> +<li style="font-family: 'Courier New', Courier, monospace; color: black; font-weight: normal; font-style: normal;"><div style="font-family: 'Courier New', Courier, monospace; font-weight: normal;"><span style="color: #66cc66;">)</span>;</div></li></ol></div></div></div> + + </div> + </div> +</div> + <hr /> + + <table width="100%"> + <tr> + <td width="25%" style="text-align: left;"> + <a href="performance.classloading.html">Class Loading</a> + </td> + + <td width="50%" style="text-align: center;"> + <div class="up"><span class="up"><a href="performance.html">Zend Gdata Performance Guide</a></span><br /> + <span class="home"><a href="manual.html">Programmer's Reference Guide</a></span></div> + </td> + + <td width="25%" style="text-align: right;"> + <div class="next" style="text-align: right; float: right;"><a href="performance.localization.html">Internationalization (i18n) and Localization (l10n)</a></div> + </td> + </tr> + </table> +</td> + <td style="font-size: smaller;" width="15%"> <style type="text/css"> +#leftbar { + float: left; + width: 186px; + padding: 5px; + font-size: smaller; +} +ul.toc { + margin: 0px 5px 5px 5px; + padding: 0px; +} +ul.toc li { + font-size: 85%; + margin: 1px 0 1px 1px; + padding: 1px 0 1px 11px; + list-style-type: none; + background-repeat: no-repeat; + background-position: center left; +} +ul.toc li.header { + font-size: 115%; + padding: 5px 0px 5px 11px; + border-bottom: 1px solid #cccccc; + margin-bottom: 5px; +} +ul.toc li.active { + font-weight: bold; +} +ul.toc li a { + text-decoration: none; +} +ul.toc li a:hover { + text-decoration: underline; +} +</style> + <ul class="toc"> + <li class="header home"><a href="manual.html">Programmer's Reference Guide</a></li> + <li class="header up"><a href="manual.html">Programmer's Reference Guide</a></li> + <li class="header up"><a href="performance.html">Zend Gdata Performance Guide</a></li> + <li><a href="performance.introduction.html">Introduction</a></li> + <li><a href="performance.classloading.html">Class Loading</a></li> + <li class="active"><a href="performance.database.html">Zend_Db Performance</a></li> + <li><a href="performance.localization.html">Internationalization (i18n) and Localization (l10n)</a></li> + <li><a href="performance.view.html">View Rendering</a></li> + </ul> + </td> + </tr> +</table> +</body> +</html>
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