[lucene-solr] 07/09: @1431 std lazy fetch again.

[ma...@apache.org]

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markrmiller pushed a commit to branch reference_impl_dev
in repository https://gitbox.apache.org/repos/asf/lucene-solr.git

commit 3ed5d3b657a595b662f7d1d38cbb4c66a3dcc581
Author: markrmiller@gmail.com <ma...@gmail.com>
AuthorDate: Sat Mar 6 18:08:10 2021 -0600

    @1431 std lazy fetch again.
    
    Took 19 minutes
    
    Took 5 minutes
---
 .../apache/solr/common/cloud/ZkStateReader.java    | 45 ++++++++++------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java b/solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java
index d65c10f..4d13f11 100644
--- a/solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java
+++ b/solr/solrj/src/java/org/apache/solr/common/cloud/ZkStateReader.java
@@ -87,7 +87,7 @@ import static java.util.Collections.emptySortedSet;
 import static org.apache.solr.common.util.Utils.fromJSON;
 
 public class ZkStateReader implements SolrCloseable, Replica.NodeNameToBaseUrl {
- // public static final int STATE_UPDATE_DELAY = Integer.getInteger("solr.OverseerStateUpdateDelay", 2000);  // delay between cloud state updates
+  public static final int STATE_UPDATE_DELAY = Integer.getInteger("solr.OverseerStateUpdateDelay", 2000);  // delay between cloud state updates
   public static final String STRUCTURE_CHANGE_NOTIFIER = "_scn";
   public static final String STATE_UPDATES = "_statupdates";
 
@@ -234,6 +234,8 @@ public class ZkStateReader implements SolrCloseable, Replica.NodeNameToBaseUrl {
 
   private final Set<ClusterPropertiesListener> clusterPropertiesListeners = ConcurrentHashMap.newKeySet();
 
+  private static final long LAZY_CACHE_TIME = TimeUnit.NANOSECONDS.convert(STATE_UPDATE_DELAY, TimeUnit.MILLISECONDS);
+
   private volatile Future<?> collectionPropsCacheCleaner; // only kept to identify if the cleaner has already been started.
   private volatile String node = null;
   private volatile LiveNodeWatcher liveNodesWatcher;
@@ -662,7 +664,7 @@ public class ZkStateReader implements SolrCloseable, Replica.NodeNameToBaseUrl {
   private void refreshCollectionList() throws KeeperException, InterruptedException {
     List<String> children = null;
     try {
-      children = zkClient.getChildren(COLLECTIONS_ZKNODE, null, null,true, false);
+      children = zkClient.getChildren(COLLECTIONS_ZKNODE, null, null, true, true);
     } catch (KeeperException.NoNodeException e) {
       log.warn("Error fetching collection names: [{}]", e.getMessage());
       // fall through
@@ -745,40 +747,35 @@ public class ZkStateReader implements SolrCloseable, Replica.NodeNameToBaseUrl {
 
   private class LazyCollectionRef extends ClusterState.CollectionRef {
     private final String collName;
-    private volatile DocCollection cachedDocCollection;
+    private long lastUpdateTime;
+    private DocCollection cachedDocCollection;
 
     public LazyCollectionRef(String collName) {
       super(null);
       this.collName = collName;
+      this.lastUpdateTime = -1;
     }
 
     @Override
     public DocCollection get(boolean allowCached) {
       gets.incrementAndGet();
-
-      boolean shouldFetch = true;
-      DocCollection cached = cachedDocCollection;
-      if (cached != null) {
-        Stat exists = null;
-        try {
-          exists = zkClient.exists(getCollectionPath(collName), null, true);
-        } catch (Exception e) {
-          ParWork.propagateInterrupt(e);
-          throw new SolrException(ErrorCode.SERVER_ERROR, e);
+      if (!allowCached || lastUpdateTime < 0 || System.nanoTime() - lastUpdateTime > LAZY_CACHE_TIME) {
+        boolean shouldFetch = true;
+        if (cachedDocCollection != null) {
+          Stat exists = null;
+          try {
+            exists = zkClient.exists(getCollectionPath(collName), null, true);
+          } catch (Exception e) {
+          }
+          if (exists != null && exists.getVersion() == cachedDocCollection.getZNodeVersion()) {
+            shouldFetch = false;
+          }
         }
-        if (exists != null && exists.getVersion() == cached.getZNodeVersion()) {
-          shouldFetch = false;
+        if (shouldFetch) {
+          cachedDocCollection = getCollectionLive(ZkStateReader.this, collName);
+          lastUpdateTime = System.nanoTime();
         }
       }
-      if (shouldFetch) {
-        cached = getCollectionLive(ZkStateReader.this, collName);
-        cachedDocCollection = cached;
-        return cached;
-      }
-
-      if (log.isDebugEnabled() && cachedDocCollection == null) {
-        log.debug("cached collection is null");
-      }
       return cachedDocCollection;
     }