mirror of
https://github.com/sigmasternchen/php-doc-en
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9425da2dfa
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@308547 c90b9560-bf6c-de11-be94-00142212c4b1
507 lines
14 KiB
XML
507 lines
14 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.mysqlnd_qc_get_core_stats" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<refnamediv>
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<refname>mysqlnd_qc_get_core_stats</refname>
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<refpurpose>Statistics collected by the core of the query cache</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>array</type>
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<methodname>mysqlnd_qc_get_core_stats</methodname>
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<void />
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</methodsynopsis>
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<para>
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Returns an array of statistics collected by the core of the cache plugin.
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The same data fields will be reported for any storage handler because the
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data is collected by the core.
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</para>
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<para>
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The
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<literal>PHP</literal> configuration setting
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<literal>mysqlnd_qc.collect_statistics</literal>
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controls the collection of statistics. The collection of statistics
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is disabled by default for performance reasons.
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Disabling the collection of statistics will also disable the collection
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of time related statistics.
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</para>
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<para>
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The
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<literal>PHP</literal> configuration setting
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<literal>mysqlnd_qc.collect_time_statistics</literal> controls the
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collection of time related statistics.
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</para>
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<para>
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The scope of the core statistics is the
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<literal>PHP</literal> process.
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Depending on your deployment model a
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<literal>PHP</literal> process may handle one or multiple requests.
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</para>
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<para>
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Statistics are aggregated for all cache entries. It is not possible
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to tell how much queries originating from
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<literal>mysqli</literal>,
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<literal>PDO_MySQL</literal> or
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<literal>mysql</literal> API calls have
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contributed to the aggregated data values.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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&no.function.parameters;
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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Array of core statistics
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</para>
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<informaltable>
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<tgroup cols="3">
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<colspec colwidth="10%"/>
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<colspec colwidth="70%"/>
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<colspec colwidth="20%"/>
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<thead>
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<row>
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<entry>Statistic</entry>
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<entry>Description</entry>
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<entry>Version</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>
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<literal>cache_hit</literal>
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</entry>
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<entry>
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Statement is considered cacheable and cached data has been reused.
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Statement is considered cacheable and a cache miss happened but
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the statement got cached by someone else while we process it and thus
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we can fetch the result from the refreshed cache.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>cache_miss</literal>
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</entry>
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<entry>
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Statement is considered cacheable...
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<itemizedlist>
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<listitem>
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<para>
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... and has been added to the cache
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</para>
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</listitem>
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<listitem>
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<para>
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... but the
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<literal>PHP</literal>
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configuration directive setting of
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<literal>mysqlnd_qc.cache_no_table = 1</literal> has prevented caching.
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</para>
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</listitem>
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<listitem>
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<para>
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... but an unbuffered result set is requested.
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</para>
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</listitem>
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<listitem>
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<para>
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... but a buffered result set was empty.
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</para>
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</listitem>
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</itemizedlist>
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>cache_put</literal>
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</entry>
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<entry>
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Statement is considered cacheable and has been added to the cache.
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Take care when calculating derived statistics. Storage handler
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with a storage life time beyond process scope may report
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<literal>cache_put = 0</literal> together with
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<literal>cache_hit > 0</literal>, if another process has filled
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the cache. You may want to use
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<literal>num_entries</literal> from
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<function>mysqlnd_qc_get_cache_info</function> if the handler
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supports it (
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<literal>default</literal>,
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<literal>APC</literal>).
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_should_cache</literal>
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</entry>
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<entry>
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Statement is considered cacheable based on query string analysis.
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The statement may or may not be added to the cache. See also
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<literal>cache_put</literal>.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_should_not_cache</literal>
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</entry>
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<entry>
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Statement is considered not cacheable based on query string analysis.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_not_cached</literal>
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</entry>
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<entry>
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Statement is considered not cacheable or it is
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considered cachable but the storage handler has not returned a
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hash key for it.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_could_cache</literal>
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</entry>
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<entry>
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Statement is considered cacheable...
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<itemizedlist>
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<listitem>
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<para>
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... and statement has been run without errors
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</para>
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</listitem>
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<listitem>
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<para>
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... and meta data shows at least one column in the result set
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</para>
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</listitem>
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</itemizedlist>
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The statement may or may not be in the cache already.
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It may or may not be added to the cache later on.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_found_in_cache</literal>
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</entry>
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<entry>
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Statement is considered cacheable and we have found it in the cache
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but we have not replayed the cached data yet and we have not send
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the result set to the client yet. This is not considered
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a cache hit because the client might not fetch the result or
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the cached data may be faulty.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_uncached_other</literal>
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</entry>
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<entry>
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Statement is considered cacheable and it may or may not be in
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the cache already but either replaying cached data has failed,
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no result set is available or some other error has happened.
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</entry>
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</row>
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<row>
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<entry>
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<literal>query_uncached_no_table</literal>
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</entry>
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<entry>
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Statement has not been cached because the result set has at least
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one column which has no table name in its meta data. An example of
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such a query is
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<literal>SELECT SLEEP(1)</literal>. To cache those
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statements you have to change default value of the PHP configuration directive
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<literal>mysqlnd_qc.cache_no_table</literal> and set
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<literal>mysqlnd_qc.cache_no_table = 1</literal>. Often, it is not
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desired to cache such statements.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_uncached_use_result</literal>
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</entry>
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<entry>
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Statement would have been cached if a buffered result set
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had been used. The situation is also consiered as a cache miss and
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<literal>cache_miss</literal> will be incremented as well.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_run_time_cache_hit</literal>
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</entry>
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<entry>
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Aggregated run time (ms) of all cached queries.
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Cached queries are those which have incremented
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<literal>cache_hit</literal>.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_run_time_cache_put</literal>
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</entry>
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<entry>
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Aggregated run time (ms) of all uncached queries that
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have been put into the cache. See also
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<literal>cache_put</literal>.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_run_time_total</literal>
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</entry>
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<entry>
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Aggregated run time (ms) of all uncached and cached queries
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that have been inspected and executed by the query cache.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_store_time_cache_hit</literal>
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</entry>
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<entry>
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Aggregated store time (ms) of all cached queries.
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Cached queries are those which have incremented
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<literal>cache_hit</literal>.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_store_time_cache_put</literal>
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</entry>
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<entry>
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Aggregated store time (
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<literal>ms</literal>) of all uncached queries that
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have been put into the cache. See also
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<literal>cache_put</literal>.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>query_aggr_store_time_total</literal>
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</entry>
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<entry>
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Aggregated store time (ms) of all uncached and cached queries
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that have been inspected and executed by the query cache.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>receive_bytes_recorded</literal>
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</entry>
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<entry>
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Recorded incoming network traffic (
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<literal>bytes</literal>) send from MySQL to PHP.
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The traffic may or may not have been added to the cache. The
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traffic is the total for all queries regardless if cached or not.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>receive_bytes_replayed</literal>
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</entry>
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<entry>
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Network traffic replayed during cache. This is the total amount of
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incoming traffic saved because of the usage of the query cache plugin.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>send_bytes_recorded</literal>
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</entry>
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<entry>
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Recorded outgoing network traffic (
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<literal>bytes</literal>) send from MySQL to PHP.
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The traffic may or may not have been added to the cache. The
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traffic is the total for all queries regardless if cached or not.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>send_bytes_replayed</literal>
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</entry>
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<entry>
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Network traffic replayed during cache. This is the total amount of
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outgoing traffic saved because of the usage of the query cache plugin.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>slam_stale_refresh</literal>
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</entry>
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<entry>
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Number of cache misses which triggered serving stale data until
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the client causing the cache miss has refreshed the cache entry.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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<row>
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<entry>
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<literal>slam_stale_hit</literal>
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</entry>
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<entry>
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Number of cache hits while a stale cache entry gets refreshed.
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</entry>
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<entry>Since 1.0.0.</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<example>
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<programlisting role="php">
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<![CDATA[
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<?php
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/* Enable collection of statistics - default: disabled */
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ini_set("mysqlnd_qc.collect_statistics", 1);
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/* Enable collection of all timing related statistics -
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default: enabled but overruled by mysqlnd_qc.collect_statistics = 0 */
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ini_set("mysqlnd_qc.collect_time_statistics", 1);
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/* Populate the cache, e.g. using mysqli */
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$mysqli = new mysqli('host', 'user', 'password', 'schema');
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/* Cache miss and cache put */
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$mysqli->query("/*qc=on*/SELECT id FROM test");
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/* Cache hit */
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$mysqli->query("/*qc=on*/SELECT id FROM test");
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/* Display core statstics */
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var_dump(mysqlnd_qc_get_core_stats());
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?>
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]]>
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</programlisting>
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&examples.outputs;
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<screen>
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<![CDATA[
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array(26) {
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["cache_hit"]=>
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string(1) "1"
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["cache_miss"]=>
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string(1) "1"
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["cache_put"]=>
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string(1) "1"
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["query_should_cache"]=>
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string(1) "2"
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["query_should_not_cache"]=>
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string(1) "0"
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["query_not_cached"]=>
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string(1) "0"
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["query_could_cache"]=>
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string(1) "2"
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["query_found_in_cache"]=>
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string(1) "1"
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["query_uncached_other"]=>
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string(1) "0"
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["query_uncached_no_table"]=>
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string(1) "0"
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["query_uncached_no_result"]=>
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string(1) "0"
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["query_uncached_use_result"]=>
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string(1) "0"
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["query_aggr_run_time_cache_hit"]=>
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string(1) "4"
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["query_aggr_run_time_cache_put"]=>
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string(3) "395"
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["query_aggr_run_time_total"]=>
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string(3) "399"
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["query_aggr_store_time_cache_hit"]=>
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string(1) "2"
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["query_aggr_store_time_cache_put"]=>
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string(1) "8"
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["query_aggr_store_time_total"]=>
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string(2) "10"
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["receive_bytes_recorded"]=>
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string(2) "65"
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["receive_bytes_replayed"]=>
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string(2) "65"
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["send_bytes_recorded"]=>
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string(2) "29"
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["send_bytes_replayed"]=>
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string(2) "29"
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["slam_stale_refresh"]=>
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string(1) "0"
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["slam_stale_hit"]=>
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string(1) "0"
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["request_counter"]=>
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int(1)
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["process_hash"]=>
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int(3547549858)
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}
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]]>
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</screen>
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</example>
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</refsect1>
|
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|
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<refsect1 role="seealso">
|
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&reftitle.seealso;
|
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<para>
|
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<simplelist>
|
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<member>
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<link linkend="mysqlnd-qc.configuration">Runtime configuration</link>
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</member>
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<member>
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<link linkend="ini.mysqlnd-qc.collect-statistics">mysqlnd_qc.collect_statistics</link>
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</member>
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<member>
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<link linkend="ini.mysqlnd-qc.time-statistics">mysqlnd_qc.time_statistics</link>
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</member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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