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https://issues.apache.org/jira/browse/HBASE-15594?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15227909#comment-15227909
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Yu Li commented on HBASE-15594:
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Yes, YCSB-651 is indeed a pain to find since lots of changes from 0.98.12 to
1.1.2 and we have to debug from server to client side to locate the problem...
Checking the code, I'm afraid with {{hbase.client.ipc.pool.size}} set to 100
there would still be separate connection created for the same ConnectionId, so
the setting would cause the same problem as the YCSB-651 bug.
In our testing (i.e. 4 clients, each with 8*100 YCSB threads, 3 RS), there
would be 3200 (4*8*100) socket connections to each RS, and the total read ops
degraded from 750K/s to 580k/s (only 1 field with 128B cell, lrucache 100%
hit). And our analysis is that with such high thread number on client side,
plenty of connections would cause more context switch thus affect performance.
I'd suggest to remove the {{hbase.client.ipc.pool.size}} setting and give it
another try.
> [YCSB] Improvements
> -------------------
>
> Key: HBASE-15594
> URL: https://issues.apache.org/jira/browse/HBASE-15594
> Project: HBase
> Issue Type: Umbrella
> Reporter: stack
> Priority: Critical
>
> Running YCSB and getting good results is an arcane art. For example, in my
> testing, a few handlers (100) with as many readers as I had CPUs (48), and
> upping connections on clients to same as #cpus made for 2-3x the throughput.
> The above config changes came of lore; which configurations need tweaking is
> not obvious going by their names, there were no indications from the app on
> where/why we were blocked or on which metrics are important to consider. Nor
> was any of this stuff written down in docs.
> Even still, I am stuck trying to make use of all of the machine. I am unable
> to overrun a server though 8 client nodes trying to beat up a single node
> (workloadc, all random-read, with no data returned -p readallfields=false).
> There is also a strange phenomenon where if I add a few machines, rather than
> 3x the YCSB throughput when 3 nodes in cluster, each machine instead is doing
> about 1/3rd.
> This umbrella issue is to host items that improve our defaults and noting how
> to get good numbers running YCSB. In particular, I want to be able to
> saturate a machine.
> Here are the configs I'm currently working with. I've not done the work to
> figure client-side if they are optimal (weird is how big a difference
> client-side changes can make -- need to fix this). On my 48 cpu machine, I
> can do about 370k random reads a second from data totally cached in
> bucketcache. If I short-circuit the user gets so they don't do any work but
> return immediately, I can do 600k ops a second but the CPUs are at 60-70%
> only. I cannot get them to go above this. Working on it.
> {code}
> <property>
> <name>
> hbase.ipc.server.read.threadpool.size
> </name>
> <value>48</value>
> </property>
> <property>
> <name>
> hbase.regionserver.handler.count
> </name>
> <value>100</value>
> </property>
> <property>
> <name>
> hbase.client.ipc.pool.size
> </name>
> <value>100</value>
> </property>
> <property>
> <name>
> hbase.htable.threads.max
> </name>
> <value>48</value>
> </property>
> {code}
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