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https://issues.apache.org/jira/browse/HBASE-20542?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16516186#comment-16516186
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Eshcar Hillel commented on HBASE-20542:
---------------------------------------
Attaching the ycsb scripts used for benchmarking.
Two sets of runs [^run.sh] .
First, write-only zipfian [^workloadx] with 10 region pre-split, followed by
a read-only zipfian [^workloady] reading only one column.
Second is the standard uniform load (a), mixed read-write [^workloada] ,
read-only [^workloadc] reading all columns.
This is a comparison of the average throughput and lift vs no-IMC:
||comp || index || workloadx || workloady || load || workloada ||
workloadc ||
| NONE | - | 49,369 | 17,682 | 11,010 | 10,468 | 7,779 |
| BASIC | CAM | 57965 | 17,132 | 11,854 | 10,318 | 7,552 |
| | | +17.41% | -3.11% | +7.67% | -1.44% | -2.91% |
|BASIC| CCM | 52,296 | 16,644 | 12,140 | 9,705 | 7,465 |
| | | +6% | -6% | +10% | -7% | -4%|
> Better heap utilization for IMC with MSLABs
> -------------------------------------------
>
> Key: HBASE-20542
> URL: https://issues.apache.org/jira/browse/HBASE-20542
> Project: HBase
> Issue Type: Sub-task
> Reporter: Eshcar Hillel
> Assignee: Eshcar Hillel
> Priority: Major
> Attachments: HBASE-20542.branch-2.001.patch, run.sh, workloada,
> workloadc, workloadx, workloady
>
>
> Following HBASE-20188 we realized in-memory compaction combined with MSLABs
> may suffer from heap under-utilization due to internal fragmentation. This
> jira presents a solution to circumvent this problem. The main idea is to have
> each update operation check if it will cause overflow in the active segment
> *before* it is writing the new value (instead of checking the size after the
> write is completed), and if it is then the active segment is atomically
> swapped with a new empty segment, and is pushed (full-yet-not-overflowed) to
> the compaction pipeline. Later on the IMC deamon will run its compaction
> operation (flatten index/merge indices/data compaction) in the background.
> Some subtle concurrency issues should be handled with care. We next elaborate
> on them.
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