From 5f1e95436eac69fb7d02a538ac20b4215391e2b6 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Thu, 28 Mar 2013 13:18:30 -0700
Subject: [PATCH] Avoid sending multiple UDP packets for the same key in
 wfIncrStats().

* This should help reduce collector data loss.

Change-Id: Ibe55648422d1b8aac86dd6fa83973d3c8715b0aa
---
 includes/AutoLoader.php      |   1 +
 includes/GlobalFunctions.php |  48 +-----------
 includes/StatCounter.php     | 141 +++++++++++++++++++++++++++++++++++
 3 files changed, 145 insertions(+), 45 deletions(-)
 create mode 100644 includes/StatCounter.php

diff --git a/includes/AutoLoader.php b/includes/AutoLoader.php
index 0b3c788d61..9ef3165258 100644
--- a/includes/AutoLoader.php
+++ b/includes/AutoLoader.php
@@ -243,6 +243,7 @@ $wgAutoloadLocalClasses = array(
 	'SpecialRedirectToSpecial' => 'includes/SpecialPage.php',
 	'SquidPurgeClient' => 'includes/SquidPurgeClient.php',
 	'SquidPurgeClientPool' => 'includes/SquidPurgeClient.php',
+	'StatCounter' => 'includes/StatCounter.php',
 	'Status' => 'includes/Status.php',
 	'StreamFile' => 'includes/StreamFile.php',
 	'StringUtils' => 'includes/StringUtils.php',
diff --git a/includes/GlobalFunctions.php b/includes/GlobalFunctions.php
index 90429268e9..1a4b985c41 100644
--- a/includes/GlobalFunctions.php
+++ b/includes/GlobalFunctions.php
@@ -1177,6 +1177,8 @@ function wfLogProfilingData() {
 	global $wgRequestTime, $wgDebugLogFile, $wgDebugRawPage, $wgRequest;
 	global $wgProfileLimit, $wgUser;
 
+	StatCounter::singleton()->flush();
+
 	$profiler = Profiler::instance();
 
 	# Profiling must actually be enabled...
@@ -1240,51 +1242,7 @@ function wfLogProfilingData() {
  * @return void
  */
 function wfIncrStats( $key, $count = 1 ) {
-	global $wgStatsMethod;
-
-	$count = intval( $count );
-	if ( $count == 0 ) {
-		return;
-	}
-
-	if( $wgStatsMethod == 'udp' ) {
-		global $wgUDPProfilerHost, $wgUDPProfilerPort, $wgAggregateStatsID;
-		static $socket;
-
-		$id = $wgAggregateStatsID !== false ? $wgAggregateStatsID : wfWikiID();
-
-		if ( !$socket ) {
-			$socket = socket_create( AF_INET, SOCK_DGRAM, SOL_UDP );
-			$statline = "stats/{$id} - 1 1 1 1 1 -total\n";
-			socket_sendto(
-				$socket,
-				$statline,
-				strlen( $statline ),
-				0,
-				$wgUDPProfilerHost,
-				$wgUDPProfilerPort
-			);
-		}
-		$statline = "stats/{$id} - {$count} 1 1 1 1 {$key}\n";
-		wfSuppressWarnings();
-		socket_sendto(
-			$socket,
-			$statline,
-			strlen( $statline ),
-			0,
-			$wgUDPProfilerHost,
-			$wgUDPProfilerPort
-		);
-		wfRestoreWarnings();
-	} elseif( $wgStatsMethod == 'cache' ) {
-		global $wgMemc;
-		$key = wfMemcKey( 'stats', $key );
-		if ( is_null( $wgMemc->incr( $key, $count ) ) ) {
-			$wgMemc->add( $key, $count );
-		}
-	} else {
-		// Disabled
-	}
+	StatCounter::singleton()->incr( $key, $count );
 }
 
 /**
diff --git a/includes/StatCounter.php b/includes/StatCounter.php
new file mode 100644
index 0000000000..30e504219b
--- /dev/null
+++ b/includes/StatCounter.php
@@ -0,0 +1,141 @@
+<?php
+/**
+ * @defgroup StatCounter StatCounter
+ *
+ * StatCounter is used to increment arbitrary keys for profiling reasons.
+ * The key/values are persisted in several possible ways (see $wgStatsMethod).
+ */
+
+/**
+ * Aggregator for wfIncrStats() that batches updates per request.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup StatCounter
+ */
+
+/**
+ * Aggregator for wfIncrStats() that batches updates per request.
+ * This avoids spamming the collector many times for the same key.
+ *
+ * @ingroup StatCounter
+ */
+class StatCounter {
+	/** @var Array */
+	protected $deltas = array(); // (key => count)
+
+	protected function __construct() {}
+
+	public static function singleton() {
+		static $instance = null;
+		if ( !$instance ) {
+			$instance = new self();
+		}
+		return $instance;
+	}
+
+	/**
+	 * Increment a key by delta $count
+	 *
+	 * @param string $key
+	 * @param integer $count
+	 * @return void
+	 */
+	public function incr( $key, $count = 1 ) {
+		if ( PHP_SAPI === 'cli' ) {
+			$this->sendDelta( $key, $count );
+		} else {
+			if ( !isset( $this->deltas[$key] ) ) {
+				$this->deltas[$key] = 0;
+			}
+			$this->deltas[$key] += $count;
+		}
+	}
+
+	/**
+	 * Flush all pending deltas to persistent storage
+	 *
+	 * @return void
+	 */
+	public function flush() {
+		try {
+			foreach ( $this->deltas as $key => $count ) {
+				$this->sendDelta( $key, $count );
+			}
+		} catch ( MWException $e ) {
+			trigger_error( "Caught exception: {$e->getMessage()}");
+		}
+		$this->deltas = array();
+	}
+
+	/**
+	 * @param string $key
+	 * @param string $count
+	 * @return void
+	 */
+	protected function sendDelta( $key, $count ) {
+		global $wgStatsMethod;
+
+		$count = intval( $count );
+		if ( $count == 0 ) {
+			return;
+		}
+
+		if ( $wgStatsMethod == 'udp' ) {
+			global $wgUDPProfilerHost, $wgUDPProfilerPort, $wgAggregateStatsID;
+			static $socket;
+
+			$id = $wgAggregateStatsID !== false ? $wgAggregateStatsID : wfWikiID();
+
+			if ( !$socket ) {
+				$socket = socket_create( AF_INET, SOCK_DGRAM, SOL_UDP );
+				$statline = "stats/{$id} - 1 1 1 1 1 -total\n";
+				socket_sendto(
+					$socket,
+					$statline,
+					strlen( $statline ),
+					0,
+					$wgUDPProfilerHost,
+					$wgUDPProfilerPort
+				);
+			}
+			$statline = "stats/{$id} - {$count} 1 1 1 1 {$key}\n";
+			wfSuppressWarnings();
+			socket_sendto(
+				$socket,
+				$statline,
+				strlen( $statline ),
+				0,
+				$wgUDPProfilerHost,
+				$wgUDPProfilerPort
+			);
+			wfRestoreWarnings();
+		} elseif ( $wgStatsMethod == 'cache' ) {
+			global $wgMemc;
+			$key = wfMemcKey( 'stats', $key );
+			if ( is_null( $wgMemc->incr( $key, $count ) ) ) {
+				$wgMemc->add( $key, $count );
+			}
+		} else {
+			// Disabled
+		}
+	}
+
+	function __destruct() {
+		$this->flush();
+	}
+}
-- 
2.20.1