Fixes to RedisBagOStuff

* Avoid serializing scalars like the memcached client does.
  This means incr/decr can be fast and preserve the TTL.
* Properly call unwatch() in the cas() method.
* Made the expiry set on add() actually atomic.
* Also cleaned up the profiling calls.

bug: 56069
Change-Id: I3e0d1c4888062544c54aef32085f8ce608ff5423

diff --git a/includes/objectcache/RedisBagOStuff.php b/includes/objectcache/RedisBagOStuff.php
index 135e0e8..adcf762 100644 (file)
--- a/includes/objectcache/RedisBagOStuff.php
+++ b/includes/objectcache/RedisBagOStuff.php
@@ -55,7 +55,7 @@ class RedisBagOStuff extends BagOStuff {
         *     flap, for example if it is in swap death.
         */
        function __construct( $params ) {
-               $redisConf = array( 'serializer' => 'php' );
+               $redisConf = array( 'serializer' => 'none' ); // manage that in this class
                foreach ( array( 'connectTimeout', 'persistent', 'password' ) as $opt ) {
                        if ( isset( $params[$opt] ) ) {
                                $redisConf[$opt] = $params[$opt];
@@ -72,38 +72,38 @@ class RedisBagOStuff extends BagOStuff {
        }
 
        public function get( $key, &$casToken = null ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                try {
-                       $result = $conn->get( $key );
+                       $result = $this->unserialize( $conn->get( $key ) );
                } catch ( RedisException $e ) {
                        $result = false;
                        $this->handleException( $server, $conn, $e );
                }
                $casToken = $result;
+
                $this->logRequest( 'get', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
        public function set( $key, $value, $expiry = 0 ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                $expiry = $this->convertToRelative( $expiry );
                try {
-                       if ( !$expiry ) {
-                               // No expiry, that is very different from zero expiry in Redis
-                               $result = $conn->set( $key, $value );
+                       if ( $expiry ) {
+                               $result = $conn->setex( $key, $expiry, $this->serialize( $value ) );
                        } else {
-                               $result = $conn->setex( $key, $expiry, $value );
+                               // No expiry, that is very different from zero expiry in Redis
+                               $result = $conn->set( $key, $this->serialize( $value ) );
                        }
                } catch ( RedisException $e ) {
                        $result = false;
@@ -111,15 +111,14 @@ class RedisBagOStuff extends BagOStuff {
                }
 
                $this->logRequest( 'set', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
        public function cas( $casToken, $key, $value, $expiry = 0 ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                $expiry = $this->convertToRelative( $expiry );
@@ -127,25 +126,18 @@ class RedisBagOStuff extends BagOStuff {
                        $conn->watch( $key );
 
                        if ( $this->get( $key ) !== $casToken ) {
-                               wfProfileOut( __METHOD__ );
+                               $conn->unwatch();
                                return false;
                        }
 
+                       // multi()/exec() will fail atomically if the key changed since watch()
                        $conn->multi();
-
-                       if ( !$expiry ) {
-                               // No expiry, that is very different from zero expiry in Redis
-                               $conn->set( $key, $value );
+                       if ( $expiry ) {
+                               $conn->setex( $key, $expiry, $this->serialize( $value ) );
                        } else {
-                               $conn->setex( $key, $expiry, $value );
+                               // No expiry, that is very different from zero expiry in Redis
+                               $conn->set( $key, $this->serialize( $value ) );
                        }
-
-                       /*
-                        * multi()/exec() (transactional mode) allows multiple values to
-                        * be set/get at once and will return an array of results, in
-                        * the order they were set/get. In this case, we only set 1
-                        * value, which should (in case of success) result in true.
-                        */
                        $result = ( $conn->exec() == array( true ) );
                } catch ( RedisException $e ) {
                        $result = false;
@@ -153,15 +145,14 @@ class RedisBagOStuff extends BagOStuff {
                }
 
                $this->logRequest( 'cas', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
        public function delete( $key, $time = 0 ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                try {
@@ -172,13 +163,14 @@ class RedisBagOStuff extends BagOStuff {
                        $result = false;
                        $this->handleException( $server, $conn, $e );
                }
+
                $this->logRequest( 'delete', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
        public function getMulti( array $keys ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                $batches = array();
                $conns = array();
                foreach ( $keys as $key ) {
@@ -204,7 +196,7 @@ class RedisBagOStuff extends BagOStuff {
                                }
                                foreach ( $batchResult as $i => $value ) {
                                        if ( $value !== false ) {
-                                               $result[$batchKeys[$i]] = $value;
+                                               $result[$batchKeys[$i]] = $this->unserialize( $value );
                                        }
                                }
                        } catch ( RedisException $e ) {
@@ -214,29 +206,32 @@ class RedisBagOStuff extends BagOStuff {
 
                $this->debug( "getMulti for " . count( $keys ) . " keys " .
                        "returned " . count( $result ) . " results" );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
        public function add( $key, $value, $expiry = 0 ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                $expiry = $this->convertToRelative( $expiry );
                try {
-                       $result = $conn->setnx( $key, $value );
-                       if ( $result && $expiry ) {
+                       if ( $expiry ) {
+                               $conn->multi();
+                               $conn->setnx( $key, $this->serialize( $value ) );
                                $conn->expire( $key, $expiry );
+                               $result = ( $conn->exec() == array( true, true ) );
+                       } else {
+                               $result = $conn->setnx( $key, $this->serialize( $value ) );
                        }
                } catch ( RedisException $e ) {
                        $result = false;
                        $this->handleException( $server, $conn, $e );
                }
+
                $this->logRequest( 'add', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
@@ -245,23 +240,22 @@ class RedisBagOStuff extends BagOStuff {
         * with WATCH or scripting, but this function is rarely used.
         */
        public function replace( $key, $value, $expiry = 0 ) {
-               wfProfileIn( __METHOD__ );
+               $section = new ProfileSection( __METHOD__ );
+
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
                if ( !$conn->exists( $key ) ) {
-                       wfProfileOut( __METHOD__ );
                        return false;
                }
 
                $expiry = $this->convertToRelative( $expiry );
                try {
                        if ( !$expiry ) {
-                               $result = $conn->set( $key, $value );
+                               $result = $conn->set( $key, $this->serialize( $value ) );
                        } else {
-                               $result = $conn->setex( $key, $expiry, $value );
+                               $result = $conn->setex( $key, $expiry, $this->serialize( $value ) );
                        }
                } catch ( RedisException $e ) {
                        $result = false;
@@ -269,10 +263,57 @@ class RedisBagOStuff extends BagOStuff {
                }
 
                $this->logRequest( 'replace', $key, $server, $result );
-               wfProfileOut( __METHOD__ );
                return $result;
        }
 
+       /**
+        * Non-atomic implementation of incr().
+        *
+        * Probably all callers actually want incr() to atomically initialise
+        * values to zero if they don't exist, as provided by the Redis INCR
+        * command. But we are constrained by the memcached-like interface to
+        * return null in that case. Once the key exists, further increments are
+        * atomic.
+        */
+       public function incr( $key, $value = 1 ) {
+               $section = new ProfileSection( __METHOD__ );
+
+               list( $server, $conn ) = $this->getConnection( $key );
+               if ( !$conn ) {
+                       return false;
+               }
+               if ( !$conn->exists( $key ) ) {
+                       return null;
+               }
+               try {
+                       $result = $this->unserialize( $conn->incrBy( $key, $value ) );
+               } catch ( RedisException $e ) {
+                       $result = false;
+                       $this->handleException( $server, $conn, $e );
+               }
+
+               $this->logRequest( 'incr', $key, $server, $result );
+               return $result;
+       }
+
+       /**
+        * @param mixed $data
+        * @return string
+        */
+       protected function serialize( $data ) {
+               // Ignore digit strings and ints so INCR/DECR work
+               return ( is_int( $data ) || ctype_digit( $data ) ) ? $data : serialize( $data );
+       }
+
+       /**
+        * @param string $data
+        * @return mixed
+        */
+       protected function unserialize( $data ) {
+               // Ignore digit strings and ints so INCR/DECR work
+               return ( is_int( $data ) || ctype_digit( $data ) ) ? $data : unserialize( $data );
+       }
+
        /**
         * Get a Redis object with a connection suitable for fetching the specified key
         * @return Array (server, RedisConnRef) or (false, false)