1 files changed, 37 insertions, 0 deletions
diff --git a/container-accesslogging/src/main/java/com/yahoo/container/logging/AccessLogSampler.java b/container-accesslogging/src/main/java/com/yahoo/container/logging/AccessLogSampler.java
new file mode 100644
index 00000000000..987035bb0e9
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+++ b/container-accesslogging/src/main/java/com/yahoo/container/logging/AccessLogSampler.java
@@ -0,0 +1,37 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.logging;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Samples entries from access log. It first samples every query until it have some data, and then sub-samples
+ * much less frequently to reduce CPU usage and latency impact. It only samples successful requests and requests
+ * that starts with /search.
+ *
+ * @author dybdahl
+ */
+public class AccessLogSampler implements AccessLogInterface {
+
+    private final AtomicLong accessLineCounter = new AtomicLong(0);
+    private final CircularArrayAccessLogKeeper circularArrayAccessLogKeeper;
+
+    public AccessLogSampler(CircularArrayAccessLogKeeper circularArrayAccessLogKeeper) {
+        this.circularArrayAccessLogKeeper = circularArrayAccessLogKeeper;
+    }
+
+    @Override
+    public void log(AccessLogEntry accessLogEntry) {
+        if (accessLogEntry.getStatusCode() != 200) {
+            return;
+        }
+	String uriString = accessLogEntry.getURI().toString();
+	if (! uriString.startsWith("/search")) {
+            return;
+	}
+        final long count = accessLineCounter.incrementAndGet();
+        if (count >= CircularArrayAccessLogKeeper.SIZE && count % CircularArrayAccessLogKeeper.SIZE  != 0) {
+            return;
+        }
+        circularArrayAccessLogKeeper.addUri(uriString);
+    }
+}