mysqlnd_qc_get_cache_info
Returns information on the current handler, the number of cache entries and cache entries, if available
&reftitle.description;
array
mysqlnd_qc_get_cache_info
&reftitle.parameters;
&no.function.parameters;
&reftitle.returnvalues;
Returns information on the current handler, the number of cache entries and
cache entries, if available. If and what data will be returned for the cache
entries is subject to the active storage handler.
Storage handler are free to return any data. Storage handler are
recommended to return at least the data provided by the default handler,
if technically possible.
The scope of the information is the PHP process. Depending on the PHP deployment
model a process may serve one or more web requests.
Values are aggregated for all cache activities on a per storage handler basis.
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. Use
mysqlnd_qc_get_core_stats
to get timing data aggregated for all storage handlers.
Array of cache information
handler
string
The active storage handler.
All storage handler. Since 1.0.0.
handler_version
string
The version of the active storage handler.
All storage handler. Since 1.0.0.
num_entries
int
The number of cache entries. The value depends on the storage handler in use.
The default, APC and SQLite storage handler provide the actual
number of cache entries.
The MEMCACHE storage handler always returns 0.
MEMCACHE does not support counting the number of cache entries.
If a user defined handler is used, the number of
entries of the data property is reported.
Since 1.0.0.
data
array
The version of the active storage handler.
Additional storage handler dependent data on the cache entries.
Storage handler are requested to provide similar and comparable
information. A user defined storage handler is free to return any data.
Since 1.0.0.
The following information is provided by the default storage handler
for the data property.
The data
property holds a hash. The hash is indexed by the internal
cache entry identifier of the storage handler. The cache entry identifier
is human-readable and contains the query string leading to the cache entry.
Please, see also the example below. The following data is given for
every cache entry.
statistics
array
Statistics of the cache entry.
Since 1.0.0.
Property
Description
Version
rows
Number of rows of the cached result set.
Since 1.0.0.
stored_size
The size of the cached result set in bytes. This is the size
of the payload. The value is not suited for calculating the
total memory consumption of all cache entries including the
administrative overhead of the cache entries.
Since 1.0.0.
cache_hits
How often the cached entry has been returned.
Since 1.0.0.
run_time
Run time of the statement to which the cache entry belongs.
This is the run time of the uncached statement. It is the time
between sending the statement to MySQL receiving a reply from MySQL.
Run time saved by using the query cache plugin can be calculated
like this: cache_hits * ((run_time - avg_run_time) + (store_time - avg_store_time)).
Since 1.0.0.
store_time
Store time of the statements result set to which the cache entry belongs.
This is the time it took to fetch and store the results of the uncached
statement.
Since 1.0.0.
min_run_time
Minimum run time of the cached statement. How long it took
to find the statement in the cache.
Since 1.0.0.
min_store_time
Minimum store time of the cached statement. The time taken
for fetching the cached result set from the storage medium and
decoding
Since 1.0.0.
avg_run_time
Average run time of the cached statement.
Since 1.0.0.
avg_store_time
Average store time of the cached statement.
Since 1.0.0.
max_run_time
Average run time of the cached statement.
Since 1.0.0.
max_store_time
Average store time of the cached statement.
Since 1.0.0.
valid_until
Timestamp when the cache entry expires.
Since 1.1.0.
metadata
array
Metadata of the cache entry.
This is the metadata provided by MySQL together with the
result set of the statement in question. Different versions
of the MySQL server may return different metadata. Unlike with
some of the PHP MySQL extensions no attempt is made to hide
MySQL server version dependencies and version details from the
caller. Please, refer to the MySQL C API documentation that
belongs to the MySQL server in use for further details.
The metadata list contains one entry for every column.
Since 1.0.0.
Property
Description
Version
name
The field name. Depending on the MySQL version this
may be the fields alias name.
Since 1.0.0.
org_name
The field name.
Since 1.0.0.
table
The table name. If an alias name was used for the table, this
usually holds the alias name.
Since 1.0.0.
org_table
The table name.
Since 1.0.0.
db
The database/schema name.
Since 1.0.0.
max_length
The maximum width of the field. Details may vary by MySQL server version.
Since 1.0.0.
length
The width of the field. Details may vary by MySQL server version.
Since 1.0.0.
type
The data type of the field. Details may vary by the MySQL server in use.
This is the MySQL C API type constants value. It is recommended
to use type constants provided by the mysqli extension
to test for its meaning. You should not test for certain type values
by comparing with certain numbers.
Since 1.0.0.
The APC storage handler returns the same information
for the data property but no metadata.
The metadata of a cache entry is set to NULL.
The MEMCACHE storage handler does not fill the data property.
Statistics are not available on a per cache entry basis with the MEMCACHE storage
handler.
A user defined storage handler is free to provide any data.
&reftitle.examples;
mysqlnd_qc_get_cache_info example
The example shows the output from the built-in default storage handler.
Other storage handler may report different data.
query("/*" . MYSQLND_QC_ENABLE_SWITCH . "*/SELECT id FROM test");
/* Display cache information */
var_dump(mysqlnd_qc_get_cache_info());
?>
]]>
&examples.outputs;
int(1)
["handler"]=>
string(7) "default"
["handler_version"]=>
string(5) "1.0.0"
["data"]=>
array(1) {
["Localhost via UNIX socket 3306 user schema|/*qc=on*/SELECT id FROM test"]=>
array(2) {
["statistics"]=>
array(11) {
["rows"]=>
int(6)
["stored_size"]=>
int(101)
["cache_hits"]=>
int(0)
["run_time"]=>
int(471)
["store_time"]=>
int(27)
["min_run_time"]=>
int(0)
["max_run_time"]=>
int(0)
["min_store_time"]=>
int(0)
["max_store_time"]=>
int(0)
["avg_run_time"]=>
int(0)
["avg_store_time"]=>
int(0)
}
["metadata"]=>
array(1) {
[0]=>
array(8) {
["name"]=>
string(2) "id"
["orig_name"]=>
string(2) "id"
["table"]=>
string(4) "test"
["orig_table"]=>
string(4) "test"
["db"]=>
string(4) "schema"
["max_length"]=>
int(1)
["length"]=>
int(11)
["type"]=>
int(3)
}
}
}
}
}
]]>
&reftitle.seealso;
mysqlnd_qc_get_core_stats