[SOLR-10104] BlockDirectoryCache release hooks do not work with multiple directories

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 6.4
• Fix Version/s: 6.5, 7.0
• Component/s: hdfs
• Assignee: Mark Miller
• Reporter: Mike Drob
• Created: 08/Feb/17 20:16
• Updated: 08/Jun/19 15:32
• Resolved: 14/Feb/17 17:31

Description

https://github.com/apache/lucene-solr/blob/5738c293f0c3f346b3e3e52c937183060d59cba1/solr/core/src/java/org/apache/solr/store/blockcache/BlockDirectoryCache.java#L53

    if (releaseBlocks) {
      keysToRelease = Collections.newSetFromMap(new ConcurrentHashMap<BlockCacheKey,Boolean>(1024, 0.75f, 512));
      blockCache.setOnRelease(new OnRelease() {
        
        @Override
        public void release(BlockCacheKey key) {
          keysToRelease.remove(key);
        }
      });
    }

If we're using the global block cache option and create multiple directories using the same factory, we will lose the release hook for the first directory. I think we can verify that by creating a server with multiple cores.

Issue Links

• relates to: SOLR-9284 The HDFS BlockDirectoryCache should not let it's keysToRelease or names maps grow indefinitely.