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https://issues.apache.org/jira/browse/HBASE-30454?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Chandra Sutadi reassigned HBASE-30454:
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Assignee: Julian Chandra Sutadi
> BucketCache persistence recovery downgrades MULTI blocks to SINGLE
> ------------------------------------------------------------------
>
> Key: HBASE-30454
> URL: https://issues.apache.org/jira/browse/HBASE-30454
> Project: HBase
> Issue Type: Bug
> Reporter: Julian Chandra Sutadi
> Assignee: Julian Chandra Sutadi
> Priority: Major
>
> HBASE-29667 reported that blocks written into the BucketCache were
> initialized with MULTI priority instead of SINGLE, so the SINGLE to MULTI
> promotion on re-access never took effect. The issue was fixed by initializing
> non-memory blocks as SINGLE in the BucketEntry constructor.
> However, when the cache is restored from its persistence file
> (BucketProtoUtils.fromPB), the BucketEntry is rebuilt from its boolean
> inMemory instead of the saved priority. The constructor sets MEMORY if
> inMemory is true and SINGLE otherwise, so a persisted MULTI block comes back
> as SINGLE. After a restart, frequently accessed blocks silently lose their
> MULTI status and are more likely to be evicted until they are read again.
> {code:java}
> // BucketProtoUtils.toPB(BucketEntry): saves all three priorities
> .setPriority(toPB(entry.getPriority()))
> // BucketProtoUtils.fromPB: reduces the priority to a boolean
> new BucketEntry(..., protoValue.getCachedTime(),
> protoValue.getPriority() == BucketCacheProtos.BlockPriority.memory, //
> inMemory
> createRecycler, ByteBuffAllocator.HEAP);
> // BucketEntry constructor (fixed by HBASE-29667)
> this.priority = inMemory ? BlockPriority.MEMORY : BlockPriority.SINGLE;
> {code}
> The suggested fix is to restore the enum directly, mirroring the existing
> toPB(BlockPriority). We will submit the fix proposal soon.
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