Merge "SpecialVersion: Avoid deprecated wfMemcKey()"

[lhc/web/wiklou.git] / includes / libs / objectcache / WANObjectCache.php

diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index 75c79a9..cb1be95 100644 (file)
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -44,15 +44,20 @@ use Psr\Log\NullLogger;
  *
  * The simplest purge method is delete().
  *
- * There are two supported ways to handle broadcasted operations:
+ * There are three supported ways to handle broadcasted operations:
  *   - a) Configure the 'purge' EventRelayer to point to a valid PubSub endpoint
- *        that has subscribed listeners on the cache servers applying the cache updates.
+ *         that has subscribed listeners on the cache servers applying the cache updates.
  *   - b) Ignore the 'purge' EventRelayer configuration (default is NullEventRelayer)
- *        and set up mcrouter as the underlying cache backend, using one of the memcached
- *        BagOStuff classes as 'cache'. Use OperationSelectorRoute in the mcrouter settings
- *        to configure 'set' and 'delete' operations to go to all DCs via AllAsyncRoute and
- *        configure other operations to go to the local DC via PoolRoute (for reference,
- *        see https://github.com/facebook/mcrouter/wiki/List-of-Route-Handles).
+ *         and set up mcrouter as the underlying cache backend, using one of the memcached
+ *         BagOStuff classes as 'cache'. Use OperationSelectorRoute in the mcrouter settings
+ *         to configure 'set' and 'delete' operations to go to all DCs via AllAsyncRoute and
+ *         configure other operations to go to the local DC via PoolRoute (for reference,
+ *         see https://github.com/facebook/mcrouter/wiki/List-of-Route-Handles).
+ *   - c) Ignore the 'purge' EventRelayer configuration (default is NullEventRelayer)
+ *         and set up dynomite as cache middleware between the web servers and either
+ *         memcached or redis. This will also broadcast all key setting operations, not just purges,
+ *         which can be useful for cache warming. Writes are eventually consistent via the
+ *         Dynamo replication model (see https://github.com/Netflix/dynomite).
  *
  * Broadcasted operations like delete() and touchCheckKey() are done asynchronously
  * in all datacenters this way, though the local one should likely be near immediate.
@@ -92,6 +97,8 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
        private $callbackDepth = 0;
        /** @var mixed[] Temporary warm-up cache */
        private $warmupCache = [];
+       /** @var integer Key fetched */
+       private $warmupKeyMisses = 0;
 
        /** Max time expected to pass between delete() and DB commit finishing */
        const MAX_COMMIT_DELAY = 3;
@@ -293,10 +300,13 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                if ( $this->warmupCache ) {
                        $wrappedValues = array_intersect_key( $this->warmupCache, array_flip( $keysGet ) );
                        $keysGet = array_diff( $keysGet, array_keys( $wrappedValues ) ); // keys left to fetch
+                       $this->warmupKeyMisses += count( $keysGet );
                } else {
                        $wrappedValues = [];
                }
-               $wrappedValues += $this->cache->getMulti( $keysGet );
+               if ( $keysGet ) {
+                       $wrappedValues += $this->cache->getMulti( $keysGet );
+               }
                // Time used to compare/init "check" keys (derived after getMulti() to be pessimistic)
                $now = microtime( true );
 
@@ -1068,7 +1078,7 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
         *         // Time-to-live (in seconds)
         *         $cache::TTL_DAY,
         *         // Function that derives the new key value
-        *         return function ( $id, $oldValue, &$ttl, array &$setOpts ) {
+        *         function ( $id, $oldValue, &$ttl, array &$setOpts ) {
         *             $dbr = wfGetDB( DB_REPLICA );
         *             // Account for any snapshot/replica DB lag
         *             $setOpts += Database::getCacheSetOptions( $dbr );
@@ -1098,22 +1108,34 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
        final public function getMultiWithSetCallback(
                ArrayIterator $keyedIds, $ttl, callable $callback, array $opts = []
        ) {
-               $keysWarmUp = iterator_to_array( $keyedIds, true );
                $checkKeys = isset( $opts['checkKeys'] ) ? $opts['checkKeys'] : [];
+
+               $keysWarmUp = [];
+               // Get all the value keys to fetch...
+               foreach ( $keyedIds as $key => $id ) {
+                       $keysWarmUp[] = self::VALUE_KEY_PREFIX . $key;
+               }
+               // Get all the check keys to fetch...
                foreach ( $checkKeys as $i => $checkKeyOrKeys ) {
                        if ( is_int( $i ) ) {
-                               $keysWarmUp[] = $checkKeyOrKeys;
+                               // Single check key that applies to all value keys
+                               $keysWarmUp[] = self::TIME_KEY_PREFIX . $checkKeyOrKeys;
                        } else {
-                               $keysWarmUp = array_merge( $keysWarmUp, $checkKeyOrKeys );
+                               // List of check keys that apply to value key $i
+                               $keysWarmUp = array_merge(
+                                       $keysWarmUp,
+                                       self::prefixCacheKeys( $checkKeyOrKeys, self::TIME_KEY_PREFIX )
+                               );
                        }
                }
 
                $this->warmupCache = $this->cache->getMulti( $keysWarmUp );
                $this->warmupCache += array_fill_keys( $keysWarmUp, false );
+               $this->warmupKeyMisses = 0;
 
                // Wrap $callback to match the getWithSetCallback() format while passing $id to $callback
                $id = null;
-               $func = function ( $oldValue, &$ttl, array $setOpts, $oldAsOf ) use ( $callback, &$id ) {
+               $func = function ( $oldValue, &$ttl, array &$setOpts, $oldAsOf ) use ( $callback, &$id ) {
                        return $callback( $id, $oldValue, $ttl, $setOpts, $oldAsOf );
                };
 
@@ -1311,6 +1333,14 @@ class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
                return (int)min( $maxTTL, max( $minTTL, $factor * $age ) );
        }
 
+       /**
+        * @return integer Number of warmup key cache misses last round
+        * @since 1.30
+        */
+       public function getWarmupKeyMisses() {
+               return $this->warmupKeyMisses;
+       }
+
        /**
         * Do the actual async bus purge of a key
         *