SOLR-8869: Optionally disable printing field cache entries in SolrFieldCacheMBean

solr/CHANGES.txt

@@ -83,6 +83,8 @@ Other Changes
 * SOLR-5616: Simplifies grouping code to use ResponseBuilder.needDocList() to determine if it needs to
   generate a doc list for grouped results. (Steven Bower, Keith Laban, Dennis Gove)
 
+* SOLR-8869: Optionally disable printing field cache entries in SolrFieldCacheMBean (Gregory Chanan)
+
 ==================  6.0.0 ==================
 
 Consult the LUCENE_CHANGES.txt file for additional, low level, changes in this release

solr/core/src/java/org/apache/solr/search/SolrFieldCacheMBean.java

@@ -31,6 +31,8 @@ import org.apache.solr.core.SolrInfoMBean;
  */
 public class SolrFieldCacheMBean implements SolrInfoMBean {
 
+  private boolean disableEntryList = Boolean.getBoolean("disableSolrFieldCacheMBeanEntryList");
+
   @Override
   public String getName() { return this.getClass().getName(); }
   @Override
@@ -52,8 +54,10 @@ public class SolrFieldCacheMBean implements SolrInfoMBean {
     NamedList stats = new SimpleOrderedMap();
     String[] entries = UninvertingReader.getUninvertedStats();
     stats.add("entries_count", entries.length);
-    for (int i = 0; i < entries.length; i++) {
-      stats.add("entry#" + i, entries[i]);
+    if (!disableEntryList) {
+      for (int i = 0; i < entries.length; i++) {
+        stats.add("entry#" + i, entries[i]);
+      }
     }
     return stats;
   }

solr/core/src/test/org/apache/solr/search/TestSolrFieldCacheMBean.java

@@ -0,0 +1,61 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.solr.search;
+
+import org.apache.solr.SolrTestCaseJ4;
+import org.apache.solr.common.util.NamedList;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.invoke.MethodHandles;
+
+public class TestSolrFieldCacheMBean extends SolrTestCaseJ4 {
+
+  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  @BeforeClass
+  public static void beforeClass() throws Exception {
+    initCore("solrconfig.xml","schema-minimal.xml");
+  }
+
+  @Test
+  public void testEntryList() throws Exception {
+    // ensure entries to FieldCache
+    assertU(adoc("id", "id0"));
+    assertU(commit());
+    assertQ(req("q", "*:*", "sort", "id asc"), "//*[@numFound='1']");
+
+    SolrFieldCacheMBean mbean = new SolrFieldCacheMBean();
+    NamedList stats = mbean.getStatistics();
+    assert(new Integer(stats.get("entries_count").toString()) > 0);
+    assertNotNull(stats.get("entry#0"));
+
+    // Test again with entry list disabled
+    System.setProperty("disableSolrFieldCacheMBeanEntryList", "true");
+    try {
+      mbean = new SolrFieldCacheMBean();
+      stats = mbean.getStatistics();
+      assert(new Integer(stats.get("entries_count").toString()) > 0);
+      assertNull(stats.get("entry#0"));
+    } finally {
+      System.clearProperty("disableSolrFieldCacheMBeanEntryList");
+    }
+  }
+}