SOLR-10742: SolrCores.getNamesForCore is quite inefficient and blocks other core operations

solr/CHANGES.txt

@@ -118,6 +118,8 @@ Other Changes
 
 * SOLR-14592: Upgrade Zookeeper to 3.6.1. NOTE: this required upgrading netty to 4.1.50 (Erick Erickson)
 
+* SOLR-10742: SolrCores.getNamesForCore is quite inefficient and blocks other core operations. 
+  NOTE: this experimental method has been removed (Erick Erickson)
 
 ==================  8.6.0 ==================
 

solr/core/src/java/org/apache/solr/core/CoreContainer.java

@@ -1526,15 +1526,6 @@ public class CoreContainer {
     return solrCores.getLoadedCoreNames();
   }
 
-  /**
-   * This method is currently experimental.
-   *
-   * @return a Collection of the names that a specific core object is mapped to, there are more than one.
-   */
-  public Collection<String> getNamesForCore(SolrCore core) {
-    return solrCores.getNamesForCore(core);
-  }
-
   /**
    * get a list of all the cores that are currently known, whether currently loaded or not
    *
@@ -1542,7 +1533,6 @@ public class CoreContainer {
    */
   public Collection<String> getAllCoreNames() {
     return solrCores.getAllCoreNames();
-
   }
 
   /**

solr/core/src/java/org/apache/solr/core/SolrCore.java

@@ -1190,7 +1190,6 @@ public final class SolrCore implements SolrInfoBean, Closeable {
     parentContext.gauge(() -> isClosed() ? 0 : getIndexSize(), true, "sizeInBytes", Category.INDEX.toString());
     parentContext.gauge(() -> isClosed() ? "(closed)" : NumberUtils.readableSize(getIndexSize()), true, "size", Category.INDEX.toString());
     if (coreContainer != null) {
-      parentContext.gauge(() -> coreContainer.getNamesForCore(this), true, "aliases", Category.CORE.toString());
       final CloudDescriptor cd = getCoreDescriptor().getCloudDescriptor();
       if (cd != null) {
         parentContext.gauge(() -> {

solr/core/src/java/org/apache/solr/core/SolrCores.java

@@ -17,7 +17,6 @@
 package org.apache.solr.core;
 
 import com.google.common.collect.Lists;
-import org.apache.http.annotation.Experimental;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.common.util.ExecutorUtil;
 import org.apache.solr.logging.MDCLoggingContext;
@@ -210,28 +209,6 @@ class SolrCores {
     }
     return set;
   }
-
-  /** This method is currently experimental.
-   *
-   * @return a Collection of the names that a specific core object is mapped to, there are more than one.
-   */
-  @Experimental
-  List<String> getNamesForCore(SolrCore core) {
-    List<String> lst = new ArrayList<>();
-
-    synchronized (modifyLock) {
-      for (Map.Entry<String, SolrCore> entry : cores.entrySet()) {
-        if (core == entry.getValue()) {
-          lst.add(entry.getKey());
-        }
-      }
-      if (getTransientCacheHandler() != null) {
-        lst.addAll(getTransientCacheHandler().getNamesForCore(core));
-      }
-    }
-    return lst;
-  }
-
   /**
    * Gets a list of all cores, loaded and unloaded 
    *

solr/core/src/java/org/apache/solr/core/TransientSolrCoreCache.java

@@ -19,12 +19,8 @@ package org.apache.solr.core;
 
 
 import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
 import java.util.Set;
 
-import org.apache.http.annotation.Experimental;
-
 /**
  * The base class for custom transient core maintenance. Any custom plugin that want's to take control of transient
  * caches (i.e. any core defined with transient=true) should override this class.
@@ -105,12 +101,6 @@ public abstract class TransientSolrCoreCache {
   // Remove the core descriptor from your list of transient descriptors.
   public abstract CoreDescriptor removeTransientDescriptor(String name);
 
-  // Find all the names a specific core is mapped to. Should not return null, return empty set instead.
-  @Experimental
-  public List<String> getNamesForCore(SolrCore core) {
-    return Collections.emptyList();
-  }
-  
   /**
    * Must be called in order to free resources!
    */

solr/core/src/java/org/apache/solr/core/TransientSolrCoreCacheDefault.java

@@ -171,17 +171,6 @@ public class TransientSolrCoreCacheDefault extends TransientSolrCoreCache {
     return transientDescriptors.remove(name);
   }
 
-  @Override
-  public List<String> getNamesForCore(SolrCore core) {
-    List<String> ret = new ArrayList<>();
-    for (Map.Entry<String, SolrCore> entry : transientCores.entrySet()) {
-      if (core == entry.getValue()) {
-        ret.add(entry.getKey());
-      }
-    }
-    return ret;
-  }
-
   // For custom implementations to communicate arbitrary information as necessary.
   @Override
   public int getStatus(String coreName) { return 0; } //no_op for default handler.

solr/core/src/java/org/apache/solr/handler/export/ExportWriterStream.java

@@ -66,7 +66,7 @@ public class ExportWriterStream extends TupleStream implements Expressible {
     @Override
     public EntryWriter put(CharSequence k, Object v) throws IOException {
       if (v instanceof IteratorWriter) {
-        List lst = new ArrayList();
+        List<Object> lst = new ArrayList<>();
         ((IteratorWriter)v).toList(lst);
         v = lst;
       } else if (v instanceof MapWriter) {