mirror of
https://github.com/sigmasternchen/php-doc-en
synced 2025-03-17 01:18:55 +00:00
Quickstart: how to cache selected queries based on a pattern
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@322215 c90b9560-bf6c-de11-be94-00142212c4b1
This commit is contained in:
Ulf Wendel
parent
0d604bbc9d
commit
8244b37fb3
3 changed files with 268 additions and 2 deletions
|
|
@ -415,8 +415,8 @@
|
|||
</varlistentry>
|
||||
</variablelist>
|
||||
</para>
|
||||
|
||||
</refsect1>
|
||||
|
||||
<refsect1 role="examples">
|
||||
&reftitle.examples;
|
||||
<example>
|
||||
|
|
@ -503,7 +503,6 @@ array(4) {
|
|||
|
||||
]]>
|
||||
</screen>
|
||||
|
||||
</example>
|
||||
</refsect1>
|
||||
|
||||
|
|
|
|||
163
reference/mysqlnd_qc/functions/mysqlnd-qc-set-is-select.xml
Normal file
163
reference/mysqlnd_qc/functions/mysqlnd-qc-set-is-select.xml
Normal file
|
|
@ -0,0 +1,163 @@
|
|||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<!-- $Revision: 322131 $ -->
|
||||
|
||||
<refentry xml:id="function.mysqlnd-qc-set-is-select" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
|
||||
<refnamediv>
|
||||
<refname>mysqlnd_qc_set_is_select</refname>
|
||||
<refpurpose>Installs a callback which decides whether a statement is cached</refpurpose>
|
||||
</refnamediv>
|
||||
|
||||
<refsect1 role="description">
|
||||
&reftitle.description;
|
||||
<methodsynopsis>
|
||||
<type>mixed</type>
|
||||
<methodname>mysqlnd_qc_set_is_select</methodname>
|
||||
<methodparam>
|
||||
<type>string</type>
|
||||
<parameter>callback</parameter>
|
||||
</methodparam>
|
||||
</methodsynopsis>
|
||||
<para>
|
||||
Installs a callback which decides whether a statement is cached.
|
||||
</para>
|
||||
<para>
|
||||
There are several ways of hinting PELC/mysqlnd_qc to cache a query.
|
||||
By default, PECL/mysqlnd_qc attempts to cache a if caching of all statements
|
||||
is enabled or the query string begins with a certain SQL hint.
|
||||
The plugin internally calls a function named <literal>is_select()</literal>
|
||||
to find out. This internal function can be replaced with a user-defined callback.
|
||||
Then, the user-defined callback is responsible to decide whether the plugin
|
||||
attempts to cache a statement. Because the internal function is replaced
|
||||
with the callback, the callback gains full control. The callback is free
|
||||
to ignore the configuration setting <literal>mysqlnd_qc.cache_by_default</literal>
|
||||
and SQL hints.
|
||||
</para>
|
||||
<para>
|
||||
The callback is invoked for every statement inspected by the plugin.
|
||||
It is given the statements string as a parameter. The callback returns
|
||||
&false; if the statement shall not be cached. It returns &true; to
|
||||
make the plugin attempt to cache the statements result set, if any.
|
||||
A so-created cache entry is given the default TTL set with the
|
||||
PHP configuration directive <literal>mysqlnd_qc.ttl</literal>.
|
||||
If a different TTL shall be used, the callback returns a numeric
|
||||
value to be used as the TTL.
|
||||
</para>
|
||||
<para>
|
||||
The internal <literal>is_select</literal> function is part of the internal
|
||||
cache storage handler interface. Thus, a user-defined storage handler
|
||||
offers the same capabilities.
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1 role="parameters">
|
||||
&reftitle.parameters;
|
||||
&no.function.parameters;
|
||||
</refsect1>
|
||||
|
||||
<refsect1 role="returnvalues">
|
||||
&reftitle.returnvalues;
|
||||
<para>
|
||||
&return.success;
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
<refsect1 role="examples">
|
||||
&reftitle.examples;
|
||||
<example>
|
||||
<para>
|
||||
|
||||
</para>
|
||||
<programlisting role="php">
|
||||
<![CDATA[
|
||||
<?php
|
||||
/* callback which decides if query is cached */
|
||||
function is_select($query) {
|
||||
static $patterns = array(
|
||||
/* true - use default from mysqlnd_qc.ttl */
|
||||
"@SELECT\s+.*\s+FROM\s+test@ismU" => true,
|
||||
/* 3 - use TTL = 3 seconds */
|
||||
"@SELECT\s+.*\s+FROM\s+news@ismU" => 3
|
||||
);
|
||||
/* check if query does match pattern */
|
||||
foreach ($patterns as $pattern => $ttl) {
|
||||
if (preg_match($pattern, $query)) {
|
||||
printf("is_select(%45s): cache\n", $query);
|
||||
return $ttl;
|
||||
}
|
||||
}
|
||||
printf("is_select(%45s): do not cache\n", $query);
|
||||
return false;
|
||||
}
|
||||
mysqlnd_qc_set_is_select("is_select");
|
||||
|
||||
/* Connect, create and populate test table */
|
||||
$mysqli = new mysqli("host", "user", "password", "schema");
|
||||
$mysqli->query("DROP TABLE IF EXISTS test");
|
||||
$mysqli->query("CREATE TABLE test(id INT)");
|
||||
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
|
||||
|
||||
/* cache put */
|
||||
$mysqli->query("SELECT id FROM test WHERE id = 1");
|
||||
/* cache hit */
|
||||
$mysqli->query("SELECT id FROM test WHERE id = 1");
|
||||
/* cache put */
|
||||
$mysqli->query("SELECT * FROM test");
|
||||
?>
|
||||
]]>
|
||||
</programlisting>
|
||||
&examples.outputs;
|
||||
<screen>
|
||||
<![CDATA[
|
||||
is_select( DROP TABLE IF EXISTS test): do not cache
|
||||
is_select( CREATE TABLE test(id INT)): do not cache
|
||||
is_select( INSERT INTO test(id) VALUES (1), (2), (3)): do not cache
|
||||
is_select( SELECT id FROM test WHERE id = 1): cache
|
||||
is_select( SELECT id FROM test WHERE id = 1): cache
|
||||
is_select( SELECT * FROM test): cache
|
||||
]]>
|
||||
</screen>
|
||||
</example>
|
||||
</refsect1>
|
||||
|
||||
<refsect1 role="seealso">
|
||||
&reftitle.seealso;
|
||||
<para>
|
||||
<simplelist>
|
||||
<member>
|
||||
<link linkend="mysqlnd-qc.configuration">Runtime configuration</link>
|
||||
</member>
|
||||
<member>
|
||||
<link linkend="ini.mysqlnd-qc.ttl">mysqlnd_qc.ttl</link>
|
||||
</member>
|
||||
<member>
|
||||
<link linkend="ini.mysqlnd-qc.cache-by-default">mysqlnd_qc.cache_by_default</link>
|
||||
</member>
|
||||
<member>
|
||||
<function>mysqlnd_qc_set_user_handlers</function>
|
||||
</member>
|
||||
</simplelist>
|
||||
</para>
|
||||
</refsect1>
|
||||
|
||||
</refentry>
|
||||
|
||||
<!-- Keep this comment at the end of the file
|
||||
Local variables:
|
||||
mode: sgml
|
||||
sgml-omittag:t
|
||||
sgml-shorttag:t
|
||||
sgml-minimize-attributes:nil
|
||||
sgml-always-quote-attributes:t
|
||||
sgml-indent-step:1
|
||||
sgml-indent-data:t
|
||||
indent-tabs-mode:nil
|
||||
sgml-parent-document:nil
|
||||
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
|
||||
sgml-exposed-tags:nil
|
||||
sgml-local-catalogs:nil
|
||||
sgml-local-ecat-files:nil
|
||||
End:
|
||||
vim600: syn=xml fen fdm=syntax fdl=2 si
|
||||
vim: et tw=78 syn=sgml
|
||||
vi: ts=1 sw=1
|
||||
-->
|
||||
|
|
@ -661,6 +661,110 @@ Script runtime : 3 seconds
|
|||
</para>
|
||||
</section>
|
||||
|
||||
<section xml:id="mysqlnd-qc.pattern_based_caching" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
|
||||
<title>Pattern based caching</title>
|
||||
<para>
|
||||
An application has three options for telling PECL/mysqlnd_qc whether a particular
|
||||
statement shall be used. The most basic approach is to cache all statements by
|
||||
setting <literal><link linkend="mysqlnd-qc.configuration">
|
||||
mysqlnd_qc.cache_by_default = 1</link></literal>. This apporach is often of little
|
||||
practical value. But it enables users to make a quick estimation about
|
||||
the maximum performance gains from caching. An application designed to
|
||||
use a cache may able to prefix selected statements with the appropriate SQL
|
||||
hints. However, altering an applications source code may not always be possible
|
||||
or desired, for example, to avoid problems with software updates. Therefore,
|
||||
PECL/mysqlnd_qc allows setting a callback which decides if a query is to be
|
||||
cached.
|
||||
</para>
|
||||
<para>
|
||||
The callback is installed with the <function>mysqlnd_qc_set_is_select</function>
|
||||
function. The callback is given the statement string of every statement
|
||||
inspected by the plugin. Then, the callback can decide whether to cache
|
||||
the function. The callback is supposed to return <literal>FALSE</literal>
|
||||
if the statement shall not be cached. A return value of <literal>TRUE</literal>
|
||||
makes the plugin try to add the statement into the cache. The cache entry
|
||||
will be given the default TTL (<literal><link linkend="mysqlnd-qc.configuration">
|
||||
mysqlnd_qc.ttl</link></literal>). If the callback returns
|
||||
a numberical value it is used as the TTL instead of the global default.
|
||||
</para>
|
||||
<para>
|
||||
<example>
|
||||
<programlisting role="ini">
|
||||
<![CDATA[
|
||||
mysqlnd_qc.enable_qc=1
|
||||
mysqlnd_qc.collect_statistics=1
|
||||
]]>
|
||||
</programlisting>
|
||||
<programlisting role="php">
|
||||
<![CDATA[
|
||||
<?php
|
||||
/* callback which decides if query is cached */
|
||||
function is_select($query) {
|
||||
static $patterns = array(
|
||||
/* true - use default from mysqlnd_qc.ttl */
|
||||
"@SELECT\s+.*\s+FROM\s+test@ismU" => true,
|
||||
/* 3 - use TTL = 3 seconds */
|
||||
"@SELECT\s+.*\s+FROM\s+news@ismU" => 3
|
||||
);
|
||||
|
||||
/* check if query does match pattern */
|
||||
foreach ($patterns as $pattern => $ttl) {
|
||||
if (preg_match($pattern, $query)) {
|
||||
printf("is_select(%45s): cache\n", $query);
|
||||
return $ttl;
|
||||
}
|
||||
}
|
||||
printf("is_select(%45s): do not cache\n", $query);
|
||||
return false;
|
||||
}
|
||||
/* install callback */
|
||||
mysqlnd_qc_set_is_select("is_select");
|
||||
|
||||
/* Connect, create and populate test table */
|
||||
$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");
|
||||
$mysqli->query("DROP TABLE IF EXISTS test");
|
||||
$mysqli->query("CREATE TABLE test(id INT)");
|
||||
$mysqli->query("INSERT INTO test(id) VALUES (1), (2), (3)");
|
||||
|
||||
/* cache put */
|
||||
$mysqli->query("SELECT id FROM test WHERE id = 1");
|
||||
/* cache hit */
|
||||
$mysqli->query("SELECT id FROM test WHERE id = 1");
|
||||
/* cache put */
|
||||
$mysqli->query("SELECT * FROM test");
|
||||
|
||||
$stats = mysqlnd_qc_get_core_stats();
|
||||
printf("Cache put: %d\n", $stats['cache_put']);
|
||||
printf("Cache hit: %d\n", $stats['cache_hit']);
|
||||
?>
|
||||
]]>
|
||||
</programlisting>
|
||||
&examples.outputs;
|
||||
<screen>
|
||||
<![CDATA[
|
||||
is_select( DROP TABLE IF EXISTS test): do not cache
|
||||
is_select( CREATE TABLE test(id INT)): do not cache
|
||||
is_select( INSERT INTO test(id) VALUES (1), (2), (3)): do not cache
|
||||
is_select( SELECT id FROM test WHERE id = 1): cache
|
||||
is_select( SELECT id FROM test WHERE id = 1): cache
|
||||
is_select( SELECT * FROM test): cache
|
||||
Cache put: 2
|
||||
Cache hit: 1
|
||||
]]>
|
||||
</screen>
|
||||
</example>
|
||||
</para>
|
||||
<para>
|
||||
The examples callback tests if a statement string matches a pattern.
|
||||
If this is the case, it either returns <literal>TRUE</literal> to cache
|
||||
the statement using the global default TTL or an alternative TTL.
|
||||
</para>
|
||||
<para>
|
||||
To minimize application changes the callback can put into and registered
|
||||
in an auto prepend file.
|
||||
</para>
|
||||
</section>
|
||||
|
||||
<section xml:id="mysqlnd-qc.slam-defense" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
|
||||
<title>Slam defense</title>
|
||||
<para>
|
||||
|
|
|
|||
Loading…
Reference in a new issue