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https://issues.apache.org/jira/browse/HBASE-11425?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ramkrishna.s.vasudevan updated HBASE-11425:
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Attachment: GC pics with evictions_4G heap.png
Tried out the experiments in a new cluster with single node.
Loaded around 15G of data with 10 regions.
Initially configured 4G as heap space, offheap space as 5G and the bucket cache
size as 4G.
Ran a pure read workload c for 30 mins. With 50 threads. I am not running
into OOME and also the block eviction part is fine. The bigger GCs are around
450ms to 500ms. Repeated the same experiment with 10 G of heap space also.
With this configuration we are sure that evictions are happening from the
bucket cache. Attaching a GC snapshot for 5 mins captured during the workload
test.
Stack,
Also in your experiment I think your data does not fit into the bucket cache
and hence it is trying to evict. Or if it is fitting into the bucket cache,
probably that was a file that was trying to get compacted and there was a
reader referencing to it and due to the OOME the ref count decrement did not
happen and the forceful eviction was failing. Will keep checking this. Any
logs can you attach when this happened? Easier to debug (hopefully).
> Cell/DBB end-to-end on the read-path
> ------------------------------------
>
> Key: HBASE-11425
> URL: https://issues.apache.org/jira/browse/HBASE-11425
> Project: HBase
> Issue Type: Umbrella
> Components: regionserver, Scanners
> Affects Versions: 0.99.0
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Attachments: BenchmarkTestCode.zip, Benchmarks_Tests.docx, GC pics
> with evictions_4G heap.png, HBASE-11425-E2E-NotComplete.patch,
> HBASE-11425.patch, Offheap reads in HBase using BBs_V2.pdf, Offheap reads in
> HBase using BBs_final.pdf, gc.png, gets.png, heap.png, load.png, median.png
>
>
> Umbrella jira to make sure we can have blocks cached in offheap backed cache.
> In the entire read path, we can refer to this offheap buffer and avoid onheap
> copying.
> The high level items I can identify as of now are
> 1. Avoid the array() call on BB in read path.. (This is there in many
> classes. We can handle class by class)
> 2. Support Buffer based getter APIs in cell. In read path we will create a
> new Cell with backed by BB. Will need in CellComparator, Filter (like SCVF),
> CPs etc.
> 3. Avoid KeyValue.ensureKeyValue() calls in read path - This make byte copy.
> 4. Remove all CP hooks (which are already deprecated) which deal with KVs.
> (In read path)
> Will add subtasks under this.
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