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

Switch to Threaded View
HBase, mail # user - Coprocessor / threading model


Copy link to this message
-
Re: Coprocessor / threading model
Michel Segel 2013-01-13, 13:25
There are a couple of different designs that you can use to perform the write to the secondary index.

I wouldn't call this an anti-pattern... (AP's comment)

Using htablepool wouldn't be my first choice, unless you are writing to a durable queue first which then uses the pool to write to the table.  This could work as part of a more general solution to handle indexing at a more general level. But that is a longer discussion.
Sent from a remote device. Please excuse any typos...

Mike Segel

On Jan 12, 2013, at 6:06 PM, Adrien Mogenet <[EMAIL PROTECTED]> wrote:

> Hi there,
>
> I'm experiencing some issues with CP. I'm trying to implement an indexing
> solution (inspired by Annop's slides). In pre-put, I trigger another Put()
> in an external table (to build the secondary index). It works perfect for
> one client, but when I'm inserting data from 2 separate clients, I met
> issues with HTable object (the one used in pre-Put()), because it's not
> thread-safe. I decided to move on TablePool and that fixed my issue.
>
> But if I increase the write-load (and concurrency) HBase is throwing a OOM
> exception because it can't create new native threads. Looking at HBase
> metrics "threads count", I see that roughly 3500 threads are created.
>
> I'm looking for documentation about how CPs are working with threads :
> what/when should I protect against concurrency issues ? How may I solve my
> issue ?
>
> Help is welcome :-)
>
> --
> Adrien Mogenet
> 06.59.16.64.22
> http://www.mogenet.me