From 3e4df13d30a470c8b7c0542296810bdd5550e10a Mon Sep 17 00:00:00 2001
From: Bharat Viswanadham <bharat@apache.org>
Date: Tue, 1 Oct 2019 10:36:04 -0700
Subject: [PATCH] HDDS-2224. Fix loadup cache for cache cleanup policy NEVER.

---
 .../java/org/apache/hadoop/hdds/utils/db/TypedTable.java | 2 +-
 .../apache/hadoop/hdds/utils/db/cache/TableCache.java    | 9 +++++++++
 .../hadoop/hdds/utils/db/cache/TableCacheImpl.java       | 7 +++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/TypedTable.java b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/TypedTable.java
index c5f23bbf9da84..597eff1f658fe 100644
--- a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/TypedTable.java
+++ b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/TypedTable.java
@@ -104,7 +104,7 @@ public TypedTable(
           // We should build cache after OM restart when clean up policy is
           // NEVER. Setting epoch value -1, so that when it is marked for
           // delete, this will be considered for cleanup.
-          cache.put(new CacheKey<>(kv.getKey()),
+          cache.loadInitial(new CacheKey<>(kv.getKey()),
               new CacheValue<>(Optional.of(kv.getValue()), EPOCH_DEFAULT));
         }
       }
diff --git a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCache.java b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCache.java
index 1f16969a3ba1a..de5a07978f51e 100644
--- a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCache.java
+++ b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCache.java
@@ -43,6 +43,15 @@ public interface TableCache<CACHEKEY extends CacheKey,
    */
   CACHEVALUE get(CACHEKEY cacheKey);
 
+  /**
+   * This method should be called for tables with cache cleanup policy
+   * {@link TableCacheImpl.CacheCleanupPolicy#NEVER} after system restart to
+   * fill up the cache.
+   * @param cacheKey
+   * @param cacheValue
+   */
+  void loadInitial(CACHEKEY cacheKey, CACHEVALUE cacheValue);
+
   /**
    * Add an entry to the cache, if the key already exists it overrides.
    * @param cacheKey
diff --git a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCacheImpl.java b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCacheImpl.java
index f33136bdba8e9..c3215c475eb9b 100644
--- a/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCacheImpl.java
+++ b/hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/utils/db/cache/TableCacheImpl.java
@@ -70,6 +70,13 @@ public CACHEVALUE get(CACHEKEY cachekey) {
     return cache.get(cachekey);
   }
 
+  @Override
+  public void loadInitial(CACHEKEY cacheKey, CACHEVALUE cacheValue) {
+    // No need to add entry to epochEntries. Adding to cache is required during
+    // normal put operation.
+    cache.put(cacheKey, cacheValue);
+  }
+
   @Override
   public void put(CACHEKEY cacheKey, CACHEVALUE value) {
     cache.put(cacheKey, value);