[HDFS-8892] ShortCircuitCache.CacheCleaner can add Slot.isInvalid() check too

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.7.1
• Component/s: hdfs-client
• Assignee: Kanaka Kumar Avvaru
• Reporter: Ravikumar
• Created: 13/Aug/15 11:42
• Updated: 29/Sep/20 18:15

Description

Currently CacheCleaner thread checks only for cache-expiry times. It would be nice if it handles an invalid-slot too in an extra-pass of evictable map…

for(ShortCircuitReplica replica:evictable.values()) {
if(!scr.getSlot().isValid())

{ purge(replica); }

}
//Existing code...
int numDemoted = demoteOldEvictableMmaped(curMs);
int numPurged = 0;
Long evictionTimeNs = Long.valueOf(0);
….
…..

Apps like HBase can tweak the expiry/staleness/cache-size params in DFS-Client, so that ShortCircuitReplica will never be closed except when Slot is declared invalid.

I assume slot-invalidation will happen during block-invalidation/deletes

{Primarily triggered by compaction/shard-takeover etc..}