SOLR-14850: Fix ExactStatsCache NullPointerException when shards.tolerant=true.

solr/CHANGES.txt

@@ -248,6 +248,9 @@ Bug Fixes
 * SOLR-14503: Use specified waitForZk value as connection timeout for zookeeper in SolrDispatcherFilter.
   Also, consume specified SOLR_WAIT_FOR_ZK in bin/solr.cmd (Colvin Cowie via Munendra S N)
 
+* SOLR-14850: Fix ExactStatsCache NullPointerException when shards.tolerant=true.
+  (Eugene Tenkaev via ab)
+
 Other Changes
 ---------------------
 

solr/core/src/java/org/apache/solr/search/stats/ExactStatsCache.java

@@ -94,6 +94,12 @@ public class ExactStatsCache extends StatsCache {
   protected void doMergeToGlobalStats(SolrQueryRequest req, List<ShardResponse> responses) {
     Set<Term> allTerms = new HashSet<>();
     for (ShardResponse r : responses) {
+      if ("true".equalsIgnoreCase(req.getParams().get(ShardParams.SHARDS_TOLERANT)) && r.getException() != null) {
+        // Can't expect stats if there was an exception for this request on any shard
+        // this should only happen when using shards.tolerant=true
+        log.debug("Exception shard response={}", r);
+        continue;
+      }
       if (log.isDebugEnabled()) {
         log.debug("Merging to global stats, shard={}, response={}", r.getShard(), r.getSolrResponse().getResponse());
       }

solr/core/src/test/org/apache/solr/search/stats/TestExactStatsCache.java

@@ -16,9 +16,81 @@
  */
 package org.apache.solr.search.stats;
 
+import org.apache.solr.client.solrj.SolrClient;
+import org.apache.solr.client.solrj.response.QueryResponse;
+import org.apache.solr.common.SolrDocumentList;
+import org.apache.solr.common.params.ModifiableSolrParams;
+import org.apache.solr.common.params.ShardParams;
+import org.junit.Test;
+
 public class TestExactStatsCache extends TestBaseStatsCache {
+  private int docId = 0;
+
   @Override
   protected String getStatsCacheClassName() {
     return ExactStatsCache.class.getName();
   }
-}
+
+  @Test
+  @ShardsFixed(num = 3)
+  public void testShardsTolerant() throws Exception {
+    del("*:*");
+    commit();
+    for (int i = 0; i < clients.size(); i++) {
+      int shard = i + 1;
+      index_specific(i, id, docId++, "a_t", "one two three",
+              "shard_i", shard);
+      index_specific(i, id, docId++, "a_t", "one two three four five",
+              "shard_i", shard);
+    }
+    commit();
+    int expectedResults = 2 * (clients.size() - 1);
+
+    checkShardsTolerantQuery(expectedResults, "q", "a_t:one", "fl", "*,score");
+  }
+
+  protected void checkShardsTolerantQuery(int expectedResults, Object... q) throws Exception {
+    final ModifiableSolrParams params = new ModifiableSolrParams();
+    for (int i = 0; i < q.length; i += 2) {
+      params.add(q[i].toString(), q[i + 1].toString());
+    }
+
+    // query a random server
+    params.set(ShardParams.SHARDS, getShardsStringWithOneDeadShard());
+    params.set(ShardParams.SHARDS_TOLERANT, "true");
+    int which = r.nextInt(clients.size());
+    SolrClient client = clients.get(which);
+    QueryResponse rsp = client.query(params);
+    checkPartialResponse(rsp, expectedResults);
+  }
+
+  protected String getShardsStringWithOneDeadShard() {
+    assertNotNull("this test requires deadServers to be non-null", deadServers);
+    assertTrue("this test requires at least 2 shards", shardsArr.length > 1);
+
+    StringBuilder sb = new StringBuilder();
+    // copy over the real shard names except for the last one,
+    // replace it with a dead server
+    for (int shardN = 0; shardN < shardsArr.length; shardN++) {
+      if (sb.length() > 0) sb.append(',');
+
+      String shard;
+      if (shardN != shardsArr.length - 1) {
+        shard = shardsArr[shardN];
+      } else {
+        if (deadServers[0].endsWith("/")) shard = deadServers[0] + DEFAULT_TEST_COLLECTION_NAME;
+        else shard = deadServers[0] + "/" + DEFAULT_TEST_CORENAME;
+      }
+      sb.append(shard);
+    }
+
+    return sb.toString();
+  }
+
+  protected void checkPartialResponse(QueryResponse response, int expectedResults) {
+    assertTrue("should have 'partialResults' in header", (Boolean)response.getHeader().get("partialResults"));
+    SolrDocumentList docList = response.getResults();
+    assertEquals(expectedResults, docList.size());
+    assertEquals(expectedResults, docList.getNumFound());
+  }
+}