[
https://issues.apache.org/jira/browse/HBASE-12790?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Andrew Purtell updated HBASE-12790:
-----------------------------------
Attachment: PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip
In the interest of moving this forward we asked the perf guys on our Phoenix
team to test HBase 0.98.16-SNAPSHOT plus HBASE-12790 and Phoenix 4.5.3-SNAPSHOT
with a small patch that allows it to take advantage of the new
Scan#getGroupingId API. The server side configuration was updated to specify
RoundRobinRPCScheduler for RPC scheduling. The comparison results are attached
as "PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip"
It's an indirect result in that we are viewing perf through the Phoenix lens,
but I'm happy to report there are no perf regressions found, only improvements.
Therefore I have no concerns in that regard about getting this committed.
I put up some comments on https://reviews.apache.org/r/32447. Getting there.
/cc [~jamestaylor]
> Support fairness across parallelized scans
> ------------------------------------------
>
> Key: HBASE-12790
> URL: https://issues.apache.org/jira/browse/HBASE-12790
> Project: HBase
> Issue Type: New Feature
> Reporter: James Taylor
> Assignee: ramkrishna.s.vasudevan
> Labels: Phoenix
> Attachments: AbstractRoundRobinQueue.java, HBASE-12790.patch,
> HBASE-12790_1.patch, HBASE-12790_5.patch, HBASE-12790_callwrapper.patch,
> HBASE-12790_trunk_1.patch, PHOENIX_4.5.3-HBase-0.98-2317-SNAPSHOT.zip
>
>
> Some HBase clients parallelize the execution of a scan to reduce latency in
> getting back results. This can lead to starvation with a loaded cluster and
> interleaved scans, since the RPC queue will be ordered and processed on a
> FIFO basis. For example, if there are two clients, A & B that submit largish
> scans at the same time. Say each scan is broken down into 100 scans by the
> client (broken down into equal depth chunks along the row key), and the 100
> scans of client A are queued first, followed immediately by the 100 scans of
> client B. In this case, client B will be starved out of getting any results
> back until the scans for client A complete.
> One solution to this is to use the attached AbstractRoundRobinQueue instead
> of the standard FIFO queue. The queue to be used could be (maybe it already
> is) configurable based on a new config parameter. Using this queue would
> require the client to have the same identifier for all of the 100 parallel
> scans that represent a single logical scan from the clients point of view.
> With this information, the round robin queue would pick off a task from the
> queue in a round robin fashion (instead of a strictly FIFO manner) to prevent
> starvation over interleaved parallelized scans.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
