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https://issues.apache.org/jira/browse/HBASE-24915?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pankaj Kumar updated HBASE-24915:
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Fix Version/s: 3.0.0-alpha-1
> Improve BlockCache read performance by specifying BlockType
> -----------------------------------------------------------
>
> Key: HBASE-24915
> URL: https://issues.apache.org/jira/browse/HBASE-24915
> Project: HBase
> Issue Type: Improvement
> Components: BlockCache, Performance
> Reporter: fanrui
> Assignee: fanrui
> Priority: Major
> Fix For: 3.0.0-alpha-1
>
>
> CombinedBlockCache contains l1Cache and l2Cache. l1Cache stores MetaBlock and
> l2Cache stores DataBlock. Because getBlock does not know the BlockType, the
> getBlock of CombinedBlockCache queries l1Cache first, and then l2Cache. But
> actually querying DataBlock is not necessary to query l1Cache.
> Therefore, in some cases where BlockType is known, BlockCache read
> performance can be improved.
> h2. Codeļ¼
> BlockCache: default call old getBlock
> {code:java}
> default Cacheable getBlock(BlockCacheKey cacheKey, boolean caching, boolean
> repeat,
> boolean updateCacheMetrics, BlockType blockType) {
> return getBlock(cacheKey, caching, repeat, updateCacheMetrics);
> }
> {code}
> CombinedBlockCache:
> {code:java}
> @Override
> public Cacheable getBlock(BlockCacheKey cacheKey, boolean caching, boolean
> repeat,
> boolean updateCacheMetrics, BlockType blockType) {
> if (blockType == null) {
> return getBlock(cacheKey, caching, repeat, updateCacheMetrics);
> }
> boolean metaBlock = isMetaBlock(blockType);
> if (metaBlock) {
> return l1Cache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
> } else {
> return l2Cache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
> }
> }private boolean isMetaBlock(BlockType blockType) {
> return blockType.getCategory() != BlockCategory.DATA;
> }
> {code}
> HFileReaderImpl#getCachedBlock call BlockCache#getBlock(XXX,
> expectedBlockType)
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