Hi,

Which version are you using?

During the 0.89 development series we got a bunch of new work in trunk
(mostly thanks to Facebook and TrendMicro) for wide rows. Maybe one of the
FB guys can comment, but I believe they have some very wide rows in their
application.

Thanks
-Todd

On Mon, Nov 22, 2010 at 2:01 AM, fnord 99 <[email protected]> wrote:

> Hi all,
>
> I recently filled an hbase table with many millions of columns in each row
> (!). The problem that now occured was that I always get a Heap Space Error
> from the JVM with a subsequent shutdown of all regionservers in which the
> error occurs. Since the error isn't thrown in any of my own classes, I
> think
> that the problem is the following:
>
> * a row is always completely read into memory upon access (at least all
> column families that I'm interested in)
> * the Result object holds the complete family-qualifier-value pairs in a
> KeyValue[]
> * this is sometimes too much to be handled by the physical memory each map
> can get, therefore a heap space error is thrown
>
> My question is now: is there any lazy fetching technique implemented within
> the single key-values within one row? In my opinion it should be but I
> couldn't find anything in the source code or wiki that hints to that.
>
> Any ideas on how to go around this problem? I had the idea to rebuild the
> table schema to store more data in the row key and less data in the column
> families which would make the tables "thinner" and "longer". It would work
> in the current setup, however, it wouldn't solve the original problem...
>
> Thanks already in advance for any input on that,
>
> fnord999
>



-- 
Todd Lipcon
Software Engineer, Cloudera

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