Add debug log which print amount of used memory.

core/ArchiveProcessor/PluginsArchiver.php

@@ -14,6 +14,7 @@ use Piwik\ArchiveProcessor;
 use Piwik\DataAccess\ArchiveWriter;
 use Piwik\DataTable\Manager;
 use Piwik\Metrics;
+use Piwik\Piwik;
 use Piwik\Plugin\Archiver;
 use Piwik\Log;
 
@@ -101,6 +102,7 @@ class PluginsArchiver
             }
 
             if ($this->shouldProcessReportsForPlugin($pluginName)) {
+                $memoryUsageBeforePluginArchiving = memory_get_usage(true);
                 if ($this->isSingleSiteDayArchive) {
                     Log::debug("PluginsArchiver::%s: Archiving day reports for plugin '%s'.", __FUNCTION__, $pluginName);
 
@@ -110,6 +112,14 @@ class PluginsArchiver
 
                     $archiver->aggregateMultipleReports();
                 }
+
+                $memoryUsageInArchiving = memory_get_usage(true) - $memoryUsageBeforePluginArchiving;
+                Log::debug("PluginsArchiver::%s: Used %s memory while archiving %s reports for plugin '%s'.",
+                    __FUNCTION__,
+                    Piwik::bytesToSize($memoryUsageInArchiving),
+                    $this->isSingleSiteDayArchive ? 'day' : 'period',
+                    $pluginName
+                );
             } else {
                 Log::debug("PluginsArchiver::%s: Not archiving reports for plugin '%s'.", __FUNCTION__, $pluginName);
             }

core/Piwik.php

@@ -765,4 +765,37 @@ class Piwik
 
         return $result;
     }
+
+    /**
+     * Convert bytes to human readable format
+     *
+     * @param int $bytes Size in bytes to convert
+     * @param int $precision Precision value, default 2.
+     * @return string
+     */
+    public static function bytesToSize($bytes, $precision = 2)
+    {
+        $kilobyte = 1024;
+        $megabyte = $kilobyte * 1024;
+        $gigabyte = $megabyte * 1024;
+        $terabyte = $gigabyte * 1024;
+
+        if (($bytes >= 0) && ($bytes < $kilobyte)) {
+            return $bytes . ' B';
+
+        } elseif (($bytes >= $kilobyte) && ($bytes < $megabyte)) {
+            return round($bytes / $kilobyte, $precision) . ' KB';
+
+        } elseif (($bytes >= $megabyte) && ($bytes < $gigabyte)) {
+            return round($bytes / $megabyte, $precision) . ' MB';
+
+        } elseif (($bytes >= $gigabyte) && ($bytes < $terabyte)) {
+            return round($bytes / $gigabyte, $precision) . ' GB';
+
+        } elseif ($bytes >= $terabyte) {
+            return round($bytes / $terabyte, $precision) . ' TB';
+        } else {
+            return $bytes . ' B';
+        }
+    }
 }