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Use stock BagOStuff lock methods in MessageCache

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Change-Id: Ic77b1b0f742590a10cddc7db067a4fcff246540f
This commit is contained in:
Aaron Schulz 2015-08-19 12:27:20 -07:00
parent 4432471dab
commit b8f231420c
1 changed files with 15 additions and 60 deletions
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75
includes/cache/MessageCache.php vendored
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@ -33,17 +33,6 @@ define( 'MSG_CACHE_VERSION', 2 );
*/
define( 'MSG_LOAD_TIMEOUT', 60 );
/**
* Memcached timeout when locking a key for a writing operation.
* See MessageCache::lock()
*/
define( 'MSG_LOCK_TIMEOUT', 30 );
/**
* Number of times we will try to acquire a lock from Memcached.
* This comes in addition to MSG_LOCK_TIMEOUT.
*/
define( 'MSG_WAIT_TIMEOUT', 30 );
/**
* Message cache
* Performs various MediaWiki namespace-related functions
@ -52,6 +41,11 @@ define( 'MSG_WAIT_TIMEOUT', 30 );
class MessageCache {
const FOR_UPDATE = 1; // force message reload
/** How long memcached locks last */
const WAIT_SEC = 30;
/** How long to wait for memcached locks */
const LOCK_TTL = 30;
/**
* Process local cache of loaded messages that are defined in
* MediaWiki namespace. First array level is a language code,
@ -349,10 +343,10 @@ class MessageCache {
# Disable cache
break;
} else {
# Wait for the other thread to finish, then retry
# Wait for the other thread to finish, then retry. Normally,
# the memcached get() will then yeild the other thread's result.
$where[] = 'waited for other thread to complete';
$this->lock( $cacheKey );
$this->unlock( $cacheKey );
$this->mMemc->getScopedLock( $cacheKey, self::WAIT_SEC, self::LOCK_TTL );
}
}
}
@ -385,6 +379,9 @@ class MessageCache {
$memCache = $this->mMemc;
# Get the non-blocking status key lock. This lets the caller quickly know
# to use any stale cache lying around. Otherwise, it may do a blocking
# lock to try to obtain the messages.
$statusKey = wfMemcKey( 'messages', $code, 'status' );
if ( !$memCache->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT ) ) {
return false; // could not acquire lock
@ -403,13 +400,8 @@ class MessageCache {
# If this lock fails, it doesn't really matter, it just means the
# write is potentially non-atomic, e.g. the results of a replace()
# may be discarded.
if ( $this->lock( $cacheKey ) ) {
$that = $this;
$mainUnlocker = new ScopedCallback( function () use ( $that, $cacheKey ) {
$that->unlock( $cacheKey );
} );
} else {
$mainUnlocker = null;
$mainUnlocker = $memCache->getScopedLock( $cacheKey, self::WAIT_SEC, self::LOCK_TTL );
if ( !$mainUnlocker ) {
$where[] = 'could not acquire main lock';
}
@ -557,7 +549,7 @@ class MessageCache {
}
$cacheKey = wfMemcKey( 'messages', $code );
$this->lock( $cacheKey );
$scopedLock = $this->mMemc->getScopedLock( $cacheKey, self::WAIT_SEC, self::LOCK_TTL );
$this->load( $code, self::FOR_UPDATE );
$titleKey = wfMemcKey( 'messages', 'individual', $title );
@ -577,7 +569,7 @@ class MessageCache {
# Update caches
$this->saveToCaches( $this->mCache[$code], 'all', $code );
$this->unlock( $cacheKey );
ScopedCallback::consume( $scopedLock );
$this->wanCache->touchCheckKey( wfMemcKey( 'messages', $code ) );
// Also delete cached sidebar... just in case it is affected
@ -681,43 +673,6 @@ class MessageCache {
);
}
/**
* Represents a write lock on the messages key.
*
* Will retry MessageCache::MSG_WAIT_TIMEOUT times, each operations having
* a timeout of MessageCache::MSG_LOCK_TIMEOUT.
*
* @param string $key
* @return bool Success
*/
function lock( $key ) {
$lockKey = $key . ':lock';
$acquired = false;
$testDone = false;
for ( $i = 0; $i < MSG_WAIT_TIMEOUT && !$acquired; $i++ ) {
$acquired = $this->mMemc->add( $lockKey, 1, MSG_LOCK_TIMEOUT );
if ( $acquired ) {
break;
}
# Fail fast if memcached is totally down
if ( !$testDone ) {
$testDone = true;
if ( !$this->mMemc->set( wfMemcKey( 'test' ), 'test', 1 ) ) {
break;
}
}
sleep( 1 );
}
return $acquired;
}
function unlock( $key ) {
$lockKey = $key . ':lock';
$this->mMemc->delete( $lockKey );
}
/**
* Get a message from either the content language or the user language.
*