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https://issues.apache.org/jira/browse/HBASE-5973?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon updated HBASE-5973:
-------------------------------
Attachment: hbase-5973.txt
Attached patch removes the unused method that Ted noticed.
I checked for a performance degradation by running the following in shell:
4.times { count 'usertable', INTERVAL => 100000, CACHE => 1000 }
on a 4-million row table generated by ycsb, after major compaction.
I measured the elapsed User CPU on the server, and the wall clock on the client.
with patch:
client side: 149.8 wall clock
server side: 1m52.03 user table
without patch:
client side: 153.3 wall clock
server side: 1m51.4 user time
These results seem to indicate there's no appreciable performance difference -
just noise. Makes sense since ThreadLocal lookups and uncontended
synchronization are both very cheap.
> Add ability for potentially long-running IPC calls to abort if client
> disconnects
> ---------------------------------------------------------------------------------
>
> Key: HBASE-5973
> URL: https://issues.apache.org/jira/browse/HBASE-5973
> Project: HBase
> Issue Type: Improvement
> Components: ipc
> Affects Versions: 0.90.7, 0.92.1, 0.94.0, 0.96.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: hbase-5973.txt, hbase-5973.txt
>
>
> We recently had a cluster issue where a user was submitting scanners with a
> very restrictive filter, and then calling next() with a high scanner caching
> value. The clients would generally time out the next() call and disconnect,
> but the IPC kept running looking to fill the requested number of rows. Since
> this was in the context of MR, the tasks making the calls would retry, and
> the retries wuld be more likely to time out due to contention with the
> previous still-running scanner next() call. Eventually, the system spiraled
> out of control.
> We should add a hook to the IPC system so that RPC calls can check if the
> client has already disconnected. In such a case, the next() call could abort
> processing, given any further work is wasted. I imagine coprocessor
> endpoints, etc, could make good use of this as well.
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