function.pg-trace.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Enable tracing a PostgreSQL connection</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pg-set-error-verbosity.html">pg_set_error_verbosity</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pg-transaction-status.html">pg_transaction_status</a></div> <div class="up"><a href="ref.pgsql.html">PostgreSQL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.pg-trace" class="refentry"> <div class="refnamediv"> <h1 class="refname">pg_trace</h1> <p class="verinfo">(PHP 4 >= 4.0.1, PHP 5)</p><p class="refpurpose"><span class="refname">pg_trace</span> — <span class="dc-title">Enable tracing a PostgreSQL connection</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>pg_trace</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$pathname</tt></span> [, <span class="methodparam"><span class="type">string</span> <tt class="parameter">$mode</tt></span> [, <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$connection</tt></span> ]] )</div> <p class="para rdfs-comment"> <b>pg_trace()</b> enables tracing of the PostgreSQL frontend/backend communication to a file. To fully understand the results, one needs to be familiar with the internals of PostgreSQL communication protocol. </p> <p class="para">For those who are not, it can still be useful for tracing errors in queries sent to the server, you could do for example <strong class="command">grep '^To backend' trace.log</strong> and see what queries actually were sent to the PostgreSQL server. For more information, refer to the <a href="http://www.postgresql.org/docs/current/interactive/" class="link external">» PostgreSQL Documentation</a>. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">pathname</tt></i></span> <dd> <p class="para"> The full path and file name of the file in which to write the trace log. Same as in <a href="function.fopen.html" class="function">fopen()</a>. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">pathname</tt></i></span> <dd> <p class="para"> An optional file access mode, same as for <a href="function.fopen.html" class="function">fopen()</a>. Defaults to "w". </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">connection</tt></i></span> <dd> <p class="para"> PostgreSQL database connection resource. When <i><tt class="parameter">connection</tt></i> is not present, the default connection is used. The default connection is the last connection made by <a href="function.pg-connect.html" class="function">pg_connect()</a> or <a href="function.pg-pconnect.html" class="function">pg_pconnect()</a>. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>pg_trace()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$pgsql_conn </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"dbname=mark host=localhost"</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">$pgsql_conn</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">pg_trace</span><span style="color: #007700">(</span><span style="color: #DD0000">'/tmp/trace.log'</span><span style="color: #007700">, </span><span style="color: #DD0000">'w'</span><span style="color: #007700">, </span><span style="color: #0000BB">$pgsql_conn</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">pg_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT 1"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">pg_untrace</span><span style="color: #007700">(</span><span style="color: #0000BB">$pgsql_conn</span><span style="color: #007700">);<br /> </span><span style="color: #FF8000">// Now /tmp/trace.log will contain backend communication<br /></span><span style="color: #007700">} else {<br /> print </span><span style="color: #0000BB">pg_last_error</span><span style="color: #007700">(</span><span style="color: #0000BB">$pgsql_conn</span><span style="color: #007700">);<br /> exit;<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.fopen.html" class="function" rel="rdfs-seeAlso">fopen()</a></li> <li class="member"><a href="function.pg-untrace.html" class="function" rel="rdfs-seeAlso">pg_untrace()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pg-set-error-verbosity.html">pg_set_error_verbosity</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pg-transaction-status.html">pg_transaction_status</a></div> <div class="up"><a href="ref.pgsql.html">PostgreSQL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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