[java] fix bug in getClosestServerInfo code

When client handles tablet not found error, it removes the tablet server from the RemoteTablet's locations. If all tablet servers are removed, the code in getClosestServerInfo will throw a division by zero exception. This patch fixed it and added a test to verify getClosestServerInfo returns null when all locations of a tablet are invalid. Change-Id: Ib4dc471b5044ea4b5bd6202ccd2a707d6e229ea0 Reviewed-on: http://gerrit.cloudera.org:8080/15444 Reviewed-by: Adar Dembo <[email protected]> Tested-by: Kudu Jenkins
wnch · Mar 16, 2020 · acabee5 · acabee5
1 parent c4e2561
commit acabee5
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diff --git a/java/kudu-client/src/main/java/org/apache/kudu/client/RemoteTablet.java b/java/kudu-client/src/main/java/org/apache/kudu/client/RemoteTablet.java
@@ -196,6 +196,9 @@ ServerInfo getClosestServerInfo(String location) {
     // TODO(wdberkeley): Eventually, the client might use the hierarchical
     // structure of a location to determine proximity.
     synchronized (tabletServers) {
+      if (tabletServers.isEmpty()) {
+        return null;
+      }
       ServerInfo result = null;
       List<ServerInfo> localServers = new ArrayList<>();
       List<ServerInfo> serversInSameLocation = new ArrayList<>();

diff --git a/java/kudu-client/src/test/java/org/apache/kudu/client/TestRemoteTablet.java b/java/kudu-client/src/test/java/org/apache/kudu/client/TestRemoteTablet.java
@@ -146,6 +146,19 @@ public void testNoLocalOrSameLocationReplica() {
     assertNotNull(tablet.getClosestServerInfo(kClientLocation).getUuid());
   }
 
+  @Test
+  public void testReplicaWithNoValidLocation() {
+    RemoteTablet tablet = getTablet(0, 1, 2);
+
+    // Test removing all tablet servers doesn't break.
+    for (String uuid : kUuids) {
+      assertTrue(tablet.removeTabletClient(uuid));
+    }
+    assertNull(tablet.getLeaderServerInfo());
+    assertNull(tablet.getClosestServerInfo(kNoLocation));
+    assertNull(tablet.getClosestServerInfo(kClientLocation));
+  }
+
   @Test
   public void testReplicaSelection() {
     {