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https://issues.apache.org/jira/browse/HBASE-13142?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14351690#comment-14351690
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Andrew Purtell commented on HBASE-13142:
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With this patch applied TestMetaScanner times out consistently.
{noformat}
Tests run: 2, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 92.72 sec <<<
FAILURE! - in org.apache.hadoop.hbase.client.TestMetaScanner
testConcurrentMetaScannerAndCatalogJanitor(org.apache.hadoop.hbase.client.TestMetaScanner)
Time elapsed: 85.416 sec <<< ERROR!
org.apache.hadoop.hbase.client.ScannerTimeoutException: 60334ms passed since
the last invocation, timeout is currently set to 60000
Caused by: org.apache.hadoop.hbase.ipc.RemoteWithExtrasException:
org.apache.hadoop.hbase.UnknownScannerException: Name: 372, already closed?
{noformat}
Odd, but there it is.
> [PERF] Reuse the IPCUtil#buildCellBlock buffer
> ----------------------------------------------
>
> Key: HBASE-13142
> URL: https://issues.apache.org/jira/browse/HBASE-13142
> Project: HBase
> Issue Type: Improvement
> Components: Performance
> Reporter: stack
> Assignee: stack
> Labels: beginner
> Fix For: 2.0.0, 1.1.0
>
> Attachments: 13142.txt, 13142v2.txt, 13142v3.txt, 13142v5.0.98.txt,
> 13142v5.txt, 13142v5.txt, buffers.svg, clean.svg, gc.png, gc_time_spent.png,
> hits.png, net.png, traces.2.svg, traces.svg
>
>
> Running some scan profiling, flight recorder was mildly fingering resize of
> the buffer allocated in IPCUtil#buildCellBlock as a point of contention. It
> was half-hearted blaming it for a few hundreds of ms over a five minute
> sampling with a few tens of instances showing.
> I tried then w/ flamegraph/lightweight profiler and this reported the buffer
> allocations taking 22% of our total CPU. See attachment trace.svg.
> I enabled TRACE-level logging on org.apache.hadoop.hbase.ipc.IPCUtil and
> indeed every allocation was doing a resize from initial allocation of 16k --
> the default up to 220k (this test returns ten randomly sized rows zipfian
> sized between 0 and 8k).
> Upping the allocation to 220k meant we now avoided the resize but the initial
> allocation was now blamed for 10% of allocations (see trace.2.svg attached).
> Lets do buffer reuse. Will save a bunch of allocation and CPU.
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