[hive] branch master updated: HIVE-19261: Avro SerDe's InstanceCache should not be synchronized on retrieve (Alexey Diomin via David Mollitor)

[dmollitor]

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dmollitor pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/hive.git


The following commit(s) were added to refs/heads/master by this push:
     new b846bbe  HIVE-19261: Avro SerDe's InstanceCache should not be 
synchronized on retrieve (Alexey Diomin via David Mollitor)
b846bbe is described below

commit b846bbe229b2225ff1122ec14b91ae910b73772c
Author: Alexey <xhuman...@gmail.com>
AuthorDate: Fri Jun 19 20:36:24 2020 +0700

    HIVE-19261: Avro SerDe's InstanceCache should not be synchronized on 
retrieve (Alexey Diomin via David Mollitor)
---
 .../apache/hadoop/hive/serde2/avro/InstanceCache.java | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git 
a/serde/src/java/org/apache/hadoop/hive/serde2/avro/InstanceCache.java 
b/serde/src/java/org/apache/hadoop/hive/serde2/avro/InstanceCache.java
index 2d52020..3e80576 100644
--- a/serde/src/java/org/apache/hadoop/hive/serde2/avro/InstanceCache.java
+++ b/serde/src/java/org/apache/hadoop/hive/serde2/avro/InstanceCache.java
@@ -17,9 +17,9 @@
  */
 package org.apache.hadoop.hive.serde2.avro;
 
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -35,7 +35,7 @@ import org.slf4j.LoggerFactory;
  */
 public abstract class InstanceCache<SeedObject, Instance> {
   private static final Logger LOG = 
LoggerFactory.getLogger(InstanceCache.class);
-  Map<SeedObject, Instance> cache = new HashMap<SeedObject, Instance>();
+  Map<SeedObject, Instance> cache = new ConcurrentHashMap<>();
   
   public InstanceCache() {}
 
@@ -51,20 +51,19 @@ public abstract class InstanceCache<SeedObject, Instance> {
    * Retrieve (or create if it doesn't exist) the correct Instance for this
    * SeedObject using 'seenSchemas' to resolve circular references
    */
-  public synchronized Instance retrieve(SeedObject hv,
-      Set<SeedObject> seenSchemas) throws AvroSerdeException {
+  public Instance retrieve(SeedObject hv, Set<SeedObject> seenSchemas)
+    throws AvroSerdeException {
     if(LOG.isDebugEnabled()) LOG.debug("Checking for hv: " + hv.toString());
 
     if(cache.containsKey(hv)) {
       if(LOG.isDebugEnabled()) LOG.debug("Returning cache result.");
       return cache.get(hv);
+    } else {
+      if(LOG.isDebugEnabled()) LOG.debug("Creating new instance and storing in 
cache");
+      Instance newInstance = makeInstance(hv, seenSchemas);
+      Instance cachedInstance = cache.putIfAbsent(hv, newInstance);
+      return cachedInstance == null ? newInstance : cachedInstance;
     }
-
-    if(LOG.isDebugEnabled()) LOG.debug("Creating new instance and storing in 
cache");
-
-    Instance instance = makeInstance(hv, seenSchemas);
-    cache.put(hv, instance);
-    return instance;
   }
 
   protected abstract Instance makeInstance(SeedObject hv,