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Posted to dev@hbase.apache.org by "Andrew Purtell (JIRA)" <ji...@apache.org> on 2015/11/04 04:05:27 UTC
[jira] [Created] (HBASE-14757) Reduce allocation pressure imposed
by block encoding
Andrew Purtell created HBASE-14757:
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Summary: Reduce allocation pressure imposed by block encoding
Key: HBASE-14757
URL: https://issues.apache.org/jira/browse/HBASE-14757
Project: HBase
Issue Type: Improvement
Reporter: Andrew Purtell
Assignee: Andrew Purtell
Fix For: 2.0.0, 1.2.0, 1.3.0, 0.98.17
Using Flight Recorder to look at the object allocation profiles of regionservers processing the various YCSB workloads when block encoding is enabled (specifically, FAST_DIFF, but this applies to any), we can see:
- Allocations of byte[] for block encoding contribute 40-70% of all allocation pressure in TLABs.
- Of that subset of allocation pressure, ~50-70% is byte[] for SeekerState
- Greater than 99% of allocation of byte[] outside of TLABs are for read buffers for HFileBlock#readBlockDataInternal.
This issue is for investigation of strategy for and impact of reducing that allocation pressure. Reducing allocation pressure reduces demand for GC, which reduces GC activity overall, which reduces a source of system latency.
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