[infinispan-issues] [Red Hat JIRA] (ISPN-12011) Investigate CompactionFilter for purging expired entries in RocksDB

Investigate CompactionFilter for purging expired entries in RocksDB ------------------------------------------------------------------- Key: ISPN-12011 URL: https://issues.redhat.com/browse/ISPN-12011 Project: Infinispan Issue Type: Sub-task Components: Loaders and Stores Reporter: Dan Berindei Priority: Major Fix For: 12.1.0.Final RocksDB allows the application to process/delete entries during compaction, and we could use this [CompactionFilter|https://github.com/facebook/rocksdb/blob/master/include/...] callback to implement the purging of expired entries. It's not straightforward, through: {{CompactionFilter}} must be implemented in a native (C++) library. {{rocksdb-jni}} allows using a native implementation from Java, but it does not allow defining it in Java (like it does for comparators). Potential solutions: # Write a native library implementing {{CompactionFilter}} for our current storage format # Change the value format to match the Cassandra storage format and use the predefined {{CassandraCompactionFilter}} # Revive the now-removed [LuaCompactionFilter|https://github.com/facebook/rocksdb/wiki/Lua-Compacti...] and write our filter implementation in Lua # Contribute an adapter for Java CompactionFilter implementations to the RocksDB project, inspired by the existing AbstractComparator