mysqlnd_qc_get_core_statsStatistics collected by the core of the query cache
&reftitle.description;
arraymysqlnd_qc_get_core_stats
Returns an array of statistics collected by the core of the cache plugin.
The same data fields will be reported for any storage handler because the
data is collected by the core.
The
PHP configuration setting
mysqlnd_qc.collect_statistics
controls the collection of statistics. The collection of statistics
is disabled by default for performance reasons.
Disabling the collection of statistics will also disable the collection
of time related statistics.
The
PHP configuration setting
mysqlnd_qc.collect_time_statistics controls the
collection of time related statistics.
The scope of the core statistics is the
PHP process.
Depending on your deployment model a
PHP process may handle one or multiple requests.
Statistics are aggregated for all cache entries and all storage handler.
It is not possible
to tell how much queries originating from
mysqli,
PDO_MySQL or
mysql API calls have
contributed to the aggregated data values.
&reftitle.parameters;
&no.function.parameters;
&reftitle.returnvalues;
Array of core statistics
StatisticDescriptionVersioncache_hit
Statement is considered cacheable and cached data has been reused.
Statement is considered cacheable and a cache miss happened but
the statement got cached by someone else while we process it and thus
we can fetch the result from the refreshed cache.
Since 1.0.0.cache_miss
Statement is considered cacheable...
... and has been added to the cache
... but the
PHP
configuration directive setting of
mysqlnd_qc.cache_no_table = 1 has prevented caching.
... but an unbuffered result set is requested.
... but a buffered result set was empty.
Since 1.0.0.cache_put
Statement is considered cacheable and has been added to the cache.
Take care when calculating derived statistics. Storage handler
with a storage life time beyond process scope may report
cache_put = 0 together with
cache_hit > 0, if another process has filled
the cache. You may want to use
num_entries from
mysqlnd_qc_get_cache_info if the handler
supports it (
default,
APC).
Since 1.0.0.query_should_cache
Statement is considered cacheable based on query string analysis.
The statement may or may not be added to the cache. See also
cache_put.
Since 1.0.0.query_should_not_cache
Statement is considered not cacheable based on query string analysis.
Since 1.0.0.query_not_cached
Statement is considered not cacheable or it is
considered cachable but the storage handler has not returned a
hash key for it.
Since 1.0.0.query_could_cache
Statement is considered cacheable...
... and statement has been run without errors
... and meta data shows at least one column in the result set
The statement may or may not be in the cache already.
It may or may not be added to the cache later on.
Since 1.0.0.query_found_in_cache
Statement is considered cacheable and we have found it in the cache
but we have not replayed the cached data yet and we have not send
the result set to the client yet. This is not considered
a cache hit because the client might not fetch the result or
the cached data may be faulty.
Since 1.0.0.query_uncached_other
Statement is considered cacheable and it may or may not be in
the cache already but either replaying cached data has failed,
no result set is available or some other error has happened.
query_uncached_no_table
Statement has not been cached because the result set has at least
one column which has no table name in its meta data. An example of
such a query is
SELECT SLEEP(1). To cache those
statements you have to change default value of the PHP configuration directive
mysqlnd_qc.cache_no_table and set
mysqlnd_qc.cache_no_table = 1. Often, it is not
desired to cache such statements.
Since 1.0.0.query_uncached_use_result
Statement would have been cached if a buffered result set
had been used. The situation is also considered as a cache miss and
cache_miss will be incremented as well.
Since 1.0.0.query_aggr_run_time_cache_hit
Aggregated run time (ms) of all cached queries.
Cached queries are those which have incremented
cache_hit.
Since 1.0.0.query_aggr_run_time_cache_put
Aggregated run time (ms) of all uncached queries that
have been put into the cache. See also
cache_put.
Since 1.0.0.query_aggr_run_time_total
Aggregated run time (ms) of all uncached and cached queries
that have been inspected and executed by the query cache.
Since 1.0.0.query_aggr_store_time_cache_hit
Aggregated store time (ms) of all cached queries.
Cached queries are those which have incremented
cache_hit.
Since 1.0.0.query_aggr_store_time_cache_put
Aggregated store time (
ms) of all uncached queries that
have been put into the cache. See also
cache_put.
Since 1.0.0.query_aggr_store_time_total
Aggregated store time (ms) of all uncached and cached queries
that have been inspected and executed by the query cache.
Since 1.0.0.receive_bytes_recorded
Recorded incoming network traffic (
bytes) send from MySQL to PHP.
The traffic may or may not have been added to the cache. The
traffic is the total for all queries regardless if cached or not.
Since 1.0.0.receive_bytes_replayed
Network traffic replayed during cache. This is the total amount of
incoming traffic saved because of the usage of the query cache plugin.
Since 1.0.0.send_bytes_recorded
Recorded outgoing network traffic (
bytes) send from MySQL to PHP.
The traffic may or may not have been added to the cache. The
traffic is the total for all queries regardless if cached or not.
Since 1.0.0.send_bytes_replayed
Network traffic replayed during cache. This is the total amount of
outgoing traffic saved because of the usage of the query cache plugin.
Since 1.0.0.slam_stale_refresh
Number of cache misses which triggered serving stale data until
the client causing the cache miss has refreshed the cache entry.
Since 1.0.0.slam_stale_hit
Number of cache hits while a stale cache entry gets refreshed.
Since 1.0.0.
&reftitle.examples;
<function>mysqlnd_qc_get_core_stats</function> example
query("/*qc=on*/SELECT id FROM test");
/* Cache hit */
$mysqli->query("/*qc=on*/SELECT id FROM test");
/* Display core statistics */
var_dump(mysqlnd_qc_get_core_stats());
?>
]]>
&examples.outputs;
string(1) "1"
["cache_miss"]=>
string(1) "1"
["cache_put"]=>
string(1) "1"
["query_should_cache"]=>
string(1) "2"
["query_should_not_cache"]=>
string(1) "0"
["query_not_cached"]=>
string(1) "0"
["query_could_cache"]=>
string(1) "2"
["query_found_in_cache"]=>
string(1) "1"
["query_uncached_other"]=>
string(1) "0"
["query_uncached_no_table"]=>
string(1) "0"
["query_uncached_no_result"]=>
string(1) "0"
["query_uncached_use_result"]=>
string(1) "0"
["query_aggr_run_time_cache_hit"]=>
string(1) "4"
["query_aggr_run_time_cache_put"]=>
string(3) "395"
["query_aggr_run_time_total"]=>
string(3) "399"
["query_aggr_store_time_cache_hit"]=>
string(1) "2"
["query_aggr_store_time_cache_put"]=>
string(1) "8"
["query_aggr_store_time_total"]=>
string(2) "10"
["receive_bytes_recorded"]=>
string(2) "65"
["receive_bytes_replayed"]=>
string(2) "65"
["send_bytes_recorded"]=>
string(2) "29"
["send_bytes_replayed"]=>
string(2) "29"
["slam_stale_refresh"]=>
string(1) "0"
["slam_stale_hit"]=>
string(1) "0"
["request_counter"]=>
int(1)
["process_hash"]=>
int(3547549858)
}
]]>
&reftitle.seealso;
Runtime configuration
mysqlnd_qc.collect_statistics
mysqlnd_qc.time_statistics
mysqlnd_qc_get_cache_info