Todd Lipcon created KUDU-1465:
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Summary: Large allocations for scanner result buffers harm
allocator thread caching
Key: KUDU-1465
URL: https://issues.apache.org/jira/browse/KUDU-1465
Project: Kudu
Issue Type: Bug
Components: perf
Affects Versions: 0.8.0
Reporter: Todd Lipcon
Assignee: Todd Lipcon
I was looking at the performance of a random-read stress test on a 70 node
cluster and found that threads were often spending time in allocator
contention, particularly when deallocating RpcSidecar objects. After a bit of
analysis, I determined this is because we always preallocate buffers of 1MB
(the default batch size) even if the response is only going to be a single row.
As a simple test, I used the set_flag command to drop the default batch size to
4KB, and the read throughput (reads/second) increased substantially.
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