Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase >> mail # dev >> short scans in one RPC


Copy link to this message
-
Re: short scans in one RPC
Interesting idea.
On Thu, Aug 22, 2013 at 9:53 AM, Dave Latham <[EMAIL PROTECTED]> wrote:

> I was recently dealing with a situation of the META table being slammed
> with queries for a long time.  While evaluating the problem I saw the IPCs
> being in a cycle like the following:
>
> HRegionInterface#getClosestRowBefore queueTime=200 processingTime=1 ... 444
> bytes.
> HRegionInterface#openScanner queueTime=191 processingTime=0 ... 22 bytes.
> HRegionInterface#next queueTime=154 processingTime=1 ...  4551 bytes.
> HRegionInterface#close queueTime=216 processingTime=0 ... 16 bytes.
> (rinse, repeat)
>
> I'm bumping our prefetching from 10 rows to 50 rows to help cut down on the
> number of cycles, but it also occurs to me that it's a bit painful to
> require 3 RPCs to do a short scan.
>
> What would people think about adding method for short scans which
> encapsulates (openScanner / next / close) in a single RPC?
>
> Dave
>