From 353f9226c3ba2637ddf365e53a9eb6862c7cb3af Mon Sep 17 00:00:00 2001
From: zhangduo <zhangduo@apache.org>
Date: Sat, 20 Apr 2019 07:55:34 +0800
Subject: [PATCH] HBASE-22236 AsyncNonMetaRegionLocator should not cache
 HRegionLocation with null location

---
 .../apache/hadoop/hbase/RegionLocations.java    | 17 ++++++++++++++++-
 .../hbase/client/AsyncNonMetaRegionLocator.java |  4 ++++
 .../hbase/client/AsyncRegionLocatorHelper.java  |  3 ++-
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
index f98bf03b7926..e119ebbb2fcf 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/RegionLocations.java
@@ -19,7 +19,6 @@
 package org.apache.hadoop.hbase;
 
 import java.util.Collection;
-
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.RegionReplicaUtil;
 import org.apache.hadoop.hbase.util.Bytes;
@@ -185,6 +184,22 @@ public RegionLocations remove(int replicaId) {
     return new RegionLocations(newLocations);
   }
 
+  /**
+   * Set the element to null if its getServerName method returns null. Returns null if all the
+   * elements are removed.
+   */
+  public RegionLocations removeElementsWithNullLocation() {
+    HRegionLocation[] newLocations = new HRegionLocation[locations.length];
+    boolean hasNonNullElement = false;
+    for (int i = 0; i < locations.length; i++) {
+      if (locations[i] != null && locations[i].getServerName() != null) {
+        hasNonNullElement = true;
+        newLocations[i] = locations[i];
+      }
+    }
+    return hasNonNullElement ? new RegionLocations(newLocations) : null;
+  }
+
   /**
    * Merges this RegionLocations list with the given list assuming
    * same range, and keeping the most up to date version of the
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncNonMetaRegionLocator.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncNonMetaRegionLocator.java
index bbb84d04f3a9..069a324fa949 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncNonMetaRegionLocator.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncNonMetaRegionLocator.java
@@ -314,6 +314,10 @@ private boolean onScanNext(TableName tableName, LocateRequest req, Result result
       LOG.debug("The fetched location of '{}', row='{}', locateType={} is {}", tableName,
         Bytes.toStringBinary(req.row), req.locateType, locs);
     }
+    // remove HRegionLocation with null location, i.e, getServerName returns null.
+    if (locs != null) {
+      locs = locs.removeElementsWithNullLocation();
+    }
 
     // the default region location should always be presented when fetching from meta, otherwise
     // let's fail the request.
diff --git a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegionLocatorHelper.java b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegionLocatorHelper.java
index 2836e4b11e86..5f4bc9f999fa 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegionLocatorHelper.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncRegionLocatorHelper.java
@@ -76,7 +76,8 @@ static void updateCachedLocationOnError(HRegionLocation loc, Throwable exception
       RegionMovedException rme = (RegionMovedException) cause;
       HRegionLocation newLoc =
         new HRegionLocation(loc.getRegion(), rme.getServerName(), rme.getLocationSeqNum());
-      LOG.debug("Try updating {} with the new location {} constructed by {}", loc, newLoc, rme);
+      LOG.debug("Try updating {} with the new location {} constructed by {}", loc, newLoc,
+        rme.toString());
       addToCache.accept(newLoc);
     } else {
       LOG.debug("Try removing {} from cache", loc);