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MDL-78109 core_cache: Remove harmful requirelockingwrite/read options

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These cache options are not used in core and would cause a performance
cost without any benefit if ever used. Also they don't work properly.
This commit is contained in:
sam marshall
2023-07-12 15:33:15 +01:00
parent ef93325f27
commit 8df2ac4e98
5 changed files with 21 additions and 249 deletions
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cache/classes/definition.php
Vendored
+12 -48
View File
@@ -52,14 +52,9 @@ defined('MOODLE_INTERNAL') || die();
* [bool] If set to true then only stores that can guarantee data will remain available once set will be used.
* + requiremultipleidentifiers
* [bool] If set to true then only stores that support multiple identifiers will be used.
* + requirelockingread
* [bool] If set to true then a lock will be gained before reading from the cache store. It is recommended not to use
* this setting unless 100% absolutely positively required. Remember 99.9% of caches will NOT need this setting.
* This setting will only be used for application caches presently.
* + requirelockingwrite
* [bool] If set to true then a lock will be gained before writing to the cache store. As above this is not recommended
* unless truly needed. Please think about the order of your code and deal with race conditions there first.
* This setting will only be used for application caches presently.
* + requirelockingbeforewrite
* [bool] If set to true then the system will throw an exception if you try to write to
* the cache without having a lock on the relevant keys.
* + maxsize
* [int] If set this will be used as the maximum number of entries within the cache store for this definition.
* Its important to note that cache stores don't actually have to acknowledge this setting or maintain it as a hard limit.
@@ -191,23 +186,11 @@ class cache_definition {
/**
* If set to true then we know that this definition requires the locking functionality.
* This gets set during construction based upon the settings requirelockingread and requirelockingwrite.
* This gets set during construction based upon the setting requirelockingbeforewrite.
* @var bool
*/
protected $requirelocking = false;
/**
* Set to true if this definition requires read locking.
* @var bool
*/
protected $requirelockingread = false;
/**
* Gets set to true if this definition requires write locking.
* @var bool
*/
protected $requirelockingwrite = false;
/**
* Gets set to true if this definition requires a lock to be acquired before a write is attempted.
* @var bool
@@ -361,8 +344,6 @@ class cache_definition {
$requireidentifiers = array();
$requiredataguarantee = false;
$requiremultipleidentifiers = false;
$requirelockingread = false;
$requirelockingwrite = false;
$requirelockingbeforewrite = false;
$requiresearchable = ($mode === cache_store::MODE_SESSION) ? true : false;
$maxsize = null;
@@ -397,19 +378,20 @@ class cache_definition {
}
if (array_key_exists('requirelockingread', $definition)) {
$requirelockingread = (bool)$definition['requirelockingread'];
debugging('The cache option requirelockingread is deprecated and now has no effect.',
DEBUG_DEVELOPER);
}
if (array_key_exists('requirelockingwrite', $definition)) {
$requirelockingwrite = (bool)$definition['requirelockingwrite'];
debugging('The cache option requirelockingwrite is deprecated and now has no effect. ' .
'Consider removing the option, or using requirelockingbeforewrite.',
DEBUG_DEVELOPER);
}
if (array_key_exists('requirelockingbeforewrite', $definition)) {
$requirelockingbeforewrite = (bool)$definition['requirelockingbeforewrite'];
}
if ($requirelockingbeforewrite && ($requirelockingwrite || $requirelockingread)) {
throw new coding_exception('requirelockingbeforewrite cannot be set with requirelockingread or requirelockingwrite
in a cache definition, as this will result in conflicting locks.');
}
$requirelocking = $requirelockingwrite || $requirelockingbeforewrite || $requirelockingread;
// This generic $requirelocking variable is kept in code in case we ever add
// another locking option, most obviously requirelockingbeforeread.
$requirelocking = $requirelockingbeforewrite;
if (array_key_exists('requiresearchable', $definition)) {
$requiresearchable = (bool)$definition['requiresearchable'];
@@ -535,8 +517,6 @@ class cache_definition {
$cachedefinition->requiredataguarantee = $requiredataguarantee;
$cachedefinition->requiremultipleidentifiers = $requiremultipleidentifiers;
$cachedefinition->requirelocking = $requirelocking;
$cachedefinition->requirelockingread = $requirelockingread;
$cachedefinition->requirelockingwrite = $requirelockingwrite;
$cachedefinition->requirelockingbeforewrite = $requirelockingbeforewrite;
$cachedefinition->requiresearchable = $requiresearchable;
$cachedefinition->maxsize = $maxsize;
@@ -740,22 +720,6 @@ class cache_definition {
return $this->requirelocking;
}
/**
* Returns true if this definition requires read locking.
* @return bool
*/
public function require_locking_read() {
return $this->requirelockingread;
}
/**
* Returns true if this definition requires write locking.
* @return bool
*/
public function require_locking_write() {
return $this->requirelockingwrite;
}
/**
* Returns true if this definition requires a lock to be aquired before a write is attempted.
* @return bool