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Posted to solr-user@lucene.apache.org by Jay Hill <ja...@gmail.com> on 2010/02/12 23:23:46 UTC
For caches, any reason to not set initialSize and size to the same
value?
If I've done a lot of research and have a very good idea of where my cache
sizes are having monitored the stats right before commits, is there any
reason why I wouldn't just set the initialSize and size counts to the same
values? Is there any reason to set a smaller initialSize if I know reliably
that where my limit will almost always be?
-Jay
RE: For caches, any reason to not set initialSize and size to the same value?
Posted by Fuad Efendi <fu...@efendi.ca>.
Funny, Arrays.copy() for HashMap... but something similar...
Anyway, I use same values for initial size and max size, to be safe... and
to have OOP at startup :)
> -----Original Message-----
> From: Fuad Efendi [mailto:fuad@efendi.ca]
> Sent: February-12-10 6:55 PM
> To: solr-user@lucene.apache.org; yonik@lucidimagination.com
> Subject: RE: For caches, any reason to not set initialSize and size to
> the same value?
>
> I always use initial size = max size,
> just to avoid Arrays.copyOf()...
>
> Initial (default) capacity for HashMap is 16, when it is not enough -
> array
> copy to new 32-element array, then to 64, ...
> - too much wasted space! (same for ConcurrentHashMap)
>
> Excuse me if I didn't understand the question...
>
> -Fuad
> http://www.tokenizer.ca
>
>
>
> > -----Original Message-----
> > From: yseeley@gmail.com [mailto:yseeley@gmail.com] On Behalf Of Yonik
> > Seeley
> > Sent: February-12-10 6:30 PM
> > To: solr-user@lucene.apache.org
> > Subject: Re: For caches, any reason to not set initialSize and size to
> > the same value?
> >
> > On Fri, Feb 12, 2010 at 5:23 PM, Jay Hill <ja...@gmail.com>
> > wrote:
> > > If I've done a lot of research and have a very good idea of where my
> > cache
> > > sizes are having monitored the stats right before commits, is there
> > any
> > > reason why I wouldn't just set the initialSize and size counts to
> the
> > same
> > > values? Is there any reason to set a smaller initialSize if I know
> > reliably
> > > that where my limit will almost always be?
> >
> > Probably not much...
> > The only savings will be the 8 bytes (on a 64 bit proc) per unused
> > array slot (in the HashMap).
> > Maybe we should consider removing the initialSize param from the
> > example config to reduce the amount of stuff a user needs to think
> > about.
> >
> > -Yonik
> > http://www.lucidimagination.com
>
RE: For caches, any reason to not set initialSize and size to the same value?
Posted by Fuad Efendi <fu...@efendi.ca>.
I always use initial size = max size,
just to avoid Arrays.copyOf()...
Initial (default) capacity for HashMap is 16, when it is not enough - array
copy to new 32-element array, then to 64, ...
- too much wasted space! (same for ConcurrentHashMap)
Excuse me if I didn't understand the question...
-Fuad
http://www.tokenizer.ca
> -----Original Message-----
> From: yseeley@gmail.com [mailto:yseeley@gmail.com] On Behalf Of Yonik
> Seeley
> Sent: February-12-10 6:30 PM
> To: solr-user@lucene.apache.org
> Subject: Re: For caches, any reason to not set initialSize and size to
> the same value?
>
> On Fri, Feb 12, 2010 at 5:23 PM, Jay Hill <ja...@gmail.com>
> wrote:
> > If I've done a lot of research and have a very good idea of where my
> cache
> > sizes are having monitored the stats right before commits, is there
> any
> > reason why I wouldn't just set the initialSize and size counts to the
> same
> > values? Is there any reason to set a smaller initialSize if I know
> reliably
> > that where my limit will almost always be?
>
> Probably not much...
> The only savings will be the 8 bytes (on a 64 bit proc) per unused
> array slot (in the HashMap).
> Maybe we should consider removing the initialSize param from the
> example config to reduce the amount of stuff a user needs to think
> about.
>
> -Yonik
> http://www.lucidimagination.com
Re: For caches, any reason to not set initialSize and size to the
same value?
Posted by Yonik Seeley <yo...@lucidimagination.com>.
On Fri, Feb 12, 2010 at 5:23 PM, Jay Hill <ja...@gmail.com> wrote:
> If I've done a lot of research and have a very good idea of where my cache
> sizes are having monitored the stats right before commits, is there any
> reason why I wouldn't just set the initialSize and size counts to the same
> values? Is there any reason to set a smaller initialSize if I know reliably
> that where my limit will almost always be?
Probably not much...
The only savings will be the 8 bytes (on a 64 bit proc) per unused
array slot (in the HashMap).
Maybe we should consider removing the initialSize param from the
example config to reduce the amount of stuff a user needs to think
about.
-Yonik
http://www.lucidimagination.com