saintstack commented on a change in pull request #1200: HBASE 23887 BlockCache
performance improve
URL: https://github.com/apache/hbase/pull/1200#discussion_r383669830
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File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java
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@@ -400,16 +413,24 @@ private Cacheable asReferencedHeapBlock(Cacheable buf) {
*/
@Override
public void cacheBlock(BlockCacheKey cacheKey, Cacheable buf, boolean
inMemory) {
+ if (cacheDataBlockPercent != 100 && buf.getBlockType().isData()) {
+ // Don't cache this DATA block if we have limit on BlockCache,
+ // good for performance (HBASE-23887)
+ if (cacheKey.getOffset() % 100 >= cacheDataBlockPercent) {
Review comment:
What is offset here? Bytes into a block? What is this modulus on offset
doing? We might cache only some of the data blocks?
I don't understand how this gets you the graphs you show in the JIRA. How do
you explain it?
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