db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Raymond Kroeker" <raym...@thinkparity.com>
Subject Re: Binary Stream Cleanup
Date Thu, 09 Aug 2007 23:25:05 GMT
Hi Mike,
  Thanks for the reply.  I will look into tuning to more closely meet my
needs.

Raymond

On 8/9/07, Mike Matrigali <mikem_app@sbcglobal.net> wrote:
>
> I can't be sure but this sounds like the expected memory usage for the
> default configuration of the database server.  The default page cache
> size is 1000 pages and with a blob table it is likely you have 32k page.
> Normal operation will be for derby to fill up all 1000 pages as soon
> as 1000 different pages are accessed either by reads or writes.  In your
> case your 500mb blob created more than 10,000 pages.  At that
> point it will maintain the pages in memory uses a page replacement
> algorithm to optimize hits.
>
> If you don't expect to use the db again then you can shut down the
> database and the memory should go away.  If you do not want the cache
> this big you can alter the page cache size, probably best not to set it
> smaller than ~50 pages.
>
> Raymond Kroeker wrote:
> > Hi All,
> >   Is there something special/specific I have to do after writing a large
> > binary stream to my database in order to reclaim memory resources?
> >
> >   My use-case is:
> >   1.  Create a new row containing a name, content and content size.
> > (500MB file)
> >   2.  Commit via the connection.  (autocommit is turned off)
> >
> >   What I'm noticing is that the memory usage jumps from 1.2 MB (after
> > the driver is loaded) to 41.9MB after the insertion.  After numerous
> > manual GCs the memory remains at 34MB.
> >
> >   I've made not attempt to tune page/cache sizes; is this what I'm
> missing?
> >
> > I'm using:
> >   Derby 10.2.2.0 <http://10.2.2.0>
> >   Java 1.6.0-b105
> >   Ubuntu 6.06.1 LTS
> >
> > --
> >
> --------------------------------------------------------------------------------
> > Raymond Kroeker
> > thinkParity Solutions Inc.
>



-- 
--------------------------------------------------------------------------------
Raymond Kroeker
thinkParity Solutions Inc.

Mime
View raw message