From efc32c83ba21f59e68bbfd4d56ae777251b42b8b Mon Sep 17 00:00:00 2001
From: sershe <sershe@unknown>
Date: Fri, 19 Apr 2013 02:29:54 +0000
Subject: [PATCH] HBASE-8264 expose the number of seen KVs from StoreScanner

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1469668 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hadoop/hbase/regionserver/StoreScanner.java    | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
index fe77b11fb3f..fb0ac388404 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java
@@ -73,6 +73,12 @@ public class StoreScanner extends NonLazyKeyValueScanner
   protected final long oldestUnexpiredTS;
   protected final int minVersions;
 
+  /**
+   * The number of KVs seen by the scanner. Includes explicitly skipped KVs, but not
+   * KVs skipped via seeking to next row/column. TODO: estimate them?
+   */
+  private long kvsScanned = 0;
+
   /** We don't ever expect to change this, the constant is just for clarity. */
   static final boolean LAZY_SEEK_ENABLED_BY_DEFAULT = true;
   public static final String STORESCANNER_PARALLEL_SEEK_ENABLE =
@@ -390,6 +396,7 @@ public class StoreScanner extends NonLazyKeyValueScanner
 
     int count = 0;
     LOOP: while((kv = this.heap.peek()) != null) {
+      ++kvsScanned;
       // Check that the heap gives us KVs in an increasing order.
       assert prevKV == null || comparator == null || comparator.compare(prevKV, kv) <= 0 :
         "Key " + prevKV + " followed by a " + "smaller key " + kv + " in cf " + store;
@@ -649,5 +656,12 @@ public class StoreScanner extends NonLazyKeyValueScanner
   static void enableLazySeekGlobally(boolean enable) {
     lazySeekEnabledGlobally = enable;
   }
+
+  /**
+   * @return The estimated number of KVs seen by this scanner (includes some skipped KVs).
+   */
+  public long getEstimatedNumberOfKvsScanned() {
+    return this.kvsScanned;
+  }
 }