[HBASE-28217] PrefetchExecutor should not run for files from CFs that have disabled BLOCKCACHE

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6.0, 3.0.0-alpha-4, 2.4.17, 2.5.6, 4.0.0-alpha-1
• Fix Version/s: 2.6.0, 2.4.18, 3.0.0-beta-1, 2.5.7
• Assignee: Wellington Chevreuil
• Reporter: Wellington Chevreuil
• Created: 22/Nov/23 17:36
• Updated: 26/Dec/23 10:04
• Resolved: 28/Nov/23 14:56

Description

HFilePReadReader relies on the return of CacheConfig.shouldPrefetchOnOpen return to decide if it should run the PrefetchExecutor for the files.

Currently, CacheConfig.shouldPrefetchOnOpen returns true if "hbase.rs.prefetchblocksonopen" is set to true at the config, OR PREFETCH_BLOCKS_ON_OPEN is set to true at CF level.

There's also the CacheConfig.shouldCacheDataOnRead, which returns true if both hbase.block.data.cacheonread is set to true at the config AND BLOCKCACHE is set to true at CF level.

If BLOCKCACHE is set to false at CF level, HFilePReadReader will still run the PrefetchExecutor to read all the file's blocks from the FileSystem, but then would find out the given block shouldn't be cached.

I believe we should change CacheConfig.shouldPrefetchOnOpen to return true only if CacheConfig.shouldCacheDataOnRead is also true.

Issue Links

• links to: GitHub Pull Request #5535