jenkins-bot has submitted this change and it was merged.
Change subject: Use stock BagOStuff lock methods in MessageCache
......................................................................
Use stock BagOStuff lock methods in MessageCache
Change-Id: Ic77b1b0f742590a10cddc7db067a4fcff246540f
---
M includes/cache/MessageCache.php
1 file changed, 15 insertions(+), 60 deletions(-)
Approvals:
Legoktm: Looks good to me, approved
jenkins-bot: Verified
diff --git a/includes/cache/MessageCache.php b/includes/cache/MessageCache.php
index 7945c8b..dafb59d 100644
--- a/includes/cache/MessageCache.php
+++ b/includes/cache/MessageCache.php
@@ -34,23 +34,17 @@
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
* @ingroup Cache
*/
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
@@ -349,10 +343,10 @@
# 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 @@
$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 @@
# 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 @@
}
$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 @@
# 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
@@ -679,43 +671,6 @@
$hash,
WANObjectCache::TTL_NONE
);
- }
-
- /**
- * 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 );
}
/**
--
To view, visit https://gerrit.wikimedia.org/r/232571
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: merged
Gerrit-Change-Id: Ic77b1b0f742590a10cddc7db067a4fcff246540f
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Aaron Schulz <[email protected]>
Gerrit-Reviewer: BryanDavis <[email protected]>
Gerrit-Reviewer: Legoktm <[email protected]>
Gerrit-Reviewer: jenkins-bot <>
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