Php/docs/mysqlnd-qc.set-user-handlers
Beyond TTL: user-defined storage
The query cache plugin supports the use of user-defined storage handler. User-defined storage handler can use arbitrarily complex invalidation algorithms and support arbitrary storage media.
All user-defined storage handlers have to provide a certain interface. The functions of the user-defined storage handler will be called by the core of the cache plugin. The necessary interface consists of seven public functions. Both procedural and object oriented user-defined storage handler must implement the same set of functions.
Example #1 Using a user-defined storage handler
<?php/* Enable default caching of all statements */ini_set("mysqlnd_qc.cache_by_default", 1);/* Procedural user defined storage handler functions */$__cache = array();function get_hash($host_info, $port, $user, $db, $query) { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); return md5(sprintf("%s%s%s%s%s", $host_info, $port, $user, $db, $query));}function find_query_in_cache($key) { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); if (isset($__cache[$key])) { $tmp = $__cache[$key]; if ($tmp["valid_until"] < time()) { unset($__cache[$key]); $ret = NULL; } else { $ret = $__cache[$key]["data"]; } } else { $ret = NULL; } return $ret;}function return_to_cache($key) { /* Called on cache hit after cached data has been processed, may be used for reference counting */ printf("\t%s(%d)\n", __FUNCTION__, func_num_args());}function add_query_to_cache_if_not_exists($key, $data, $ttl, $run_time, $store_time, $row_count) { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); $__cache[$key] = array( "data" => $data, "row_count" => $row_count, "valid_until" => time() + $ttl, "hits" => 0, "run_time" => $run_time, "store_time" => $store_time, "cached_run_times" => array(), "cached_store_times" => array(), ); return TRUE;}function query_is_select($query) { printf("\t%s('%s'): ", __FUNCTION__, $query); $ret = FALSE; if (stristr($query, "SELECT") !== FALSE) { /* cache for 5 seconds */ $ret = 5; } printf("%s\n", (FALSE === $ret) ? "FALSE" : $ret); return $ret;}function update_query_run_time_stats($key, $run_time, $store_time) { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); if (isset($__cache[$key])) { $__cache[$key]['hits']++; $__cache[$key]["cached_run_times"][] = $run_time; $__cache[$key]["cached_store_times"][] = $store_time; }}function get_stats($key = NULL) { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); if ($key && isset($__cache[$key])) { $stats = $__cache[$key]; } else { $stats = array(); foreach ($__cache as $key => $details) { $stats[$key] = array( 'hits' => $details['hits'], 'bytes' => strlen($details['data']), 'uncached_run_time' => $details['run_time'], 'cached_run_time' => (count($details['cached_run_times'])) ? array_sum($details['cached_run_times']) / count($details['cached_run_times']) : 0, ); } } return $stats;}function clear_cache() { global $__cache; printf("\t%s(%d)\n", __FUNCTION__, func_num_args()); $__cache = array(); return TRUE;}/* Install procedural user-defined storage handler */if (!mysqlnd_qc_set_user_handlers("get_hash", "find_query_in_cache", "return_to_cache", "add_query_to_cache_if_not_exists", "query_is_select", "update_query_run_time_stats", "get_stats", "clear_cache")) { printf("Failed to install user-defined storage handler\n");}/* Connect, create and populate test table */$mysqli = new mysqli("host", "user", "password", "schema", "port", "socket");$mysqli->query("DROP TABLE IF EXISTS test");$mysqli->query("CREATE TABLE test(id INT)");$mysqli->query("INSERT INTO test(id) VALUES (1), (2)");printf("\nCache put/cache miss\n");$res = $mysqli->query("SELECT id FROM test WHERE id = 1");var_dump($res->fetch_assoc());$res->free();/* Delete record to verify we get our data from the cache */$mysqli->query("DELETE FROM test WHERE id = 1");printf("\nCache hit\n");$res = $mysqli->query("SELECT id FROM test WHERE id = 1");var_dump($res->fetch_assoc());$res->free();printf("\nDisplay cache statistics\n");var_dump(mysqlnd_qc_get_cache_info());printf("\nFlushing cache, cache put/cache miss");var_dump(mysqlnd_qc_clear_cache());$res = $mysqli->query("SELECT id FROM test WHERE id = 1");var_dump($res->fetch_assoc());$res->free();?>
The above examples will output something similar to:
query_is_select('DROP TABLE IF EXISTS test'): FALSE
query_is_select('CREATE TABLE test(id INT)'): FALSE
query_is_select('INSERT INTO test(id) VALUES (1), (2)'): FALSE
Cache put/cache miss
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
add_query_to_cache_if_not_exists(6)
array(1) {
["id"]=>
string(1) "1"
}
query_is_select('DELETE FROM test WHERE id = 1'): FALSE
Cache hit
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
return_to_cache(1)
update_query_run_time_stats(3)
array(1) {
["id"]=>
string(1) "1"
}
Display cache statistics
get_stats(0)
array(4) {
["num_entries"]=>
int(1)
["handler"]=>
string(4) "user"
["handler_version"]=>
string(5) "1.0.0"
["data"]=>
array(1) {
["18683c177dc89bb352b29965d112fdaa"]=>
array(4) {
["hits"]=>
int(1)
["bytes"]=>
int(71)
["uncached_run_time"]=>
int(398)
["cached_run_time"]=>
int(4)
}
}
}
Flushing cache, cache put/cache miss clear_cache(0)
bool(true)
query_is_select('SELECT id FROM test WHERE id = 1'): 5
get_hash(5)
find_query_in_cache(1)
add_query_to_cache_if_not_exists(6)
NULL
