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Posted to modperl@perl.apache.org by DeWitt Clinton <de...@unto.net> on 2001/03/10 19:03:27 UTC
[ANNOUNCE] Cache-Cache-0.03
Summary:
Perl Cache is the successor to the popular File::Cache and
IPC::Cache perl libraries. This project unifies those modules under
the generic Cache::Cache interface and implements Cache::FileCache,
Cache::MemoryCache, Cache::SharedMemoryCache, and
Cache::SizeAwareFileCache.
Release Notes:
This release offers performance enhancements, expiration and size
reduction bug fixes, an improved expiration string syntax, much
better documentation, and a new cache API method.
Project Homepage:
http://sourceforge.net/projects/perl-cache/
Tar/GZ:
http://ftp1.sourceforge.net/perl-cache/Cache-Cache-0.03.tar.gz
Changelog:
http://sourceforge.net/project/shownotes.php?release_id=26779
CVS tree (cvsweb):
http://cvs.sourceforge.net/cgi-bin/cvsweb.cgi?cvsroot=perl-cache
The following is the Cache-Cache-0.03 README file:
Copyright (C) 2001 DeWitt Clinton All Rights Reserved
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
NAME
Cache::Cache
DESCRIPTION
The Perl Cache package provides Cache::Cache, a generic interface
for creating persistent data stores. This interface is implemented
by the Cache::FileCache, Cache::SizeAwareFileCache,
Cache::MemoryCache, and Cache::SharedMemoryCache classes. This work
replaces File::Cache and IPC::Cache.
REQUIREMENTS
Data::Dumper
Digest::MD5
File::Spec
File::Path
IPC::Shareable
INSTALLATION
perl Makefile.PL
make
make test
make install
USAGE
First, choose the best type of cache implementation for your needs.
The simplest cache is the MemoryCache, which is suitable for
applications that are serving multiple sequential requests, and
which to avoid making redundant expensive queries, such as an
Apache/mod_perl application talking to a database. If you wish to
share that data between processes, then perhaps the
SharedMemoryCache is appropriate, although its behavior is tightly
bound to the underlying IPC mechanism, which varies from system to
system, and is unsuitable for large objects or large numbers of
objects. When the SharedMemoryCache is not acceptable, then
FileCache offers all of the same functionality with similar
performance metrics, and it is not limited in terms of the number of
objects or their size. If you wish to maintain a strict limit on
the size of a file system based cache, then the SizeAwareFileCache
is the way to go.
Using a cache is simple. Here is some sample code for instantiating
and using a MemoryCache:
use Cache::Cache qw( $EXPIRES_NEVER $EXPIRES_NOW );
use Cache::MemoryCache;
my $options_hash_ref = { 'default_expires_in' => '10 seconds' };
my $cache = new Cache::MemoryCache( $options_hash_ref );
my $expires_in = '10 minutes';
$cache->set( 'Key', 'Value', $expires_in );
# if the next line is called within 10 minutes, then this
# will return the cache value
my $value = $cache->get( 'Key' );
Please refer to the perldoc for Cache::Cache and the related
implementations for complete documention.
SEE ALSO
File::Cache and IPC::Cache
AUTHOR
Original author: DeWitt Clinton <de...@unto.net>
Last author: $Author: dclinton $
Copyright (C) 2001 DeWitt Clinton
Re: [ANNOUNCE] Cache-Cache-0.03
Posted by DeWitt Clinton <de...@unto.net>.
On Sat, Mar 10, 2001 at 02:00:34PM -0600, Daniel Little (Metrex) wrote:
> Along the same lines, how about making SizeAwareMemoryCache as well
> so that you can specify just how much data you want stored in the
> cache.
Good idea. I'll add that to the 0.04 feature list as well.
Thanks!
-DeWitt
Re: [ANNOUNCE] Cache-Cache-0.03
Posted by DeWitt Clinton <de...@unto.net>.
On Sat, Mar 10, 2001 at 12:10:35PM -0800, Perrin Harkins wrote:
> "Daniel Little (Metrex)" wrote:
> > Along the same lines, how about making SizeAwareMemoryCache as well so that
> > you can specify just how much data you want stored in the cache.
>
> Sounds like Joshua Chamas' Tie::Cache module. It provides a
> size-limited LRU cache.
Note that Cache::SizeAwareFileCache does both a "next expiration" and
a LRU algorithm for limiting the size. I'll use the same logic for
the SizeAwareMemoryCache.
Thanks,
-DeWitt
RE: [ANNOUNCE] Cache-Cache-0.03
Posted by "Daniel Little (Metrex)" <da...@metrex.net>.
Perrin,
> "Daniel Little (Metrex)" wrote:
> > Along the same lines, how about making SizeAwareMemoryCache as
> well so that
> > you can specify just how much data you want stored in the cache.
>
> Sounds like Joshua Chamas' Tie::Cache module. It provides a
> size-limited LRU cache.
Indeed! Thanks for the tip! Just installed it and it looks like it fits the
bill perfectly.
Daniel.
Re: [ANNOUNCE] Cache-Cache-0.03
Posted by Perrin Harkins <pe...@primenet.com>.
"Daniel Little (Metrex)" wrote:
> Along the same lines, how about making SizeAwareMemoryCache as well so that
> you can specify just how much data you want stored in the cache.
Sounds like Joshua Chamas' Tie::Cache module. It provides a
size-limited LRU cache.
- Perrin
RE: [ANNOUNCE] Cache-Cache-0.03
Posted by "Daniel Little (Metrex)" <da...@metrex.net>.
DeWitt,
> > Have you though about making SharedMemoryCache flush to disk if it
> > becomes full but before it's time to expire the data?
>
> I've done a lot of thinking about a multi-layered cache
> implementation. The API would be the same, but it would be clever
> about using MemoryCache -> SharedMemoryCache -> FileCache to make read
> access to data super efficient, and only persist outward on writes.
Along the same lines, how about making SizeAwareMemoryCache as well so that
you can specify just how much data you want stored in the cache. I haven't
really thought about the implications of this but it seems to me that it
would be a useful extension. Memory's normally tighter than disk space. And
being in a mod_perl server environment where you have large chunks of memory
already used for the web server, it would be good to keep a handle on the
cache growing too large.
I suppose you get a similar effect from just keeping the timeout short but
I'm thinking of a scenario where it's valuable to keep the data for a very
long time, so long as I know that I'm not using all available memory in the
process.
Daniel.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Daniel Little Metrex Systems Consulting Inc. danl@metrex.net
210-294 William Ave. Tel: (204) 940-4553
Winnipeg, MB., Cel: (204) 955-0300
Canada, R3B 0R1 Fax: (204) 487-6680
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Re: [ANNOUNCE] Cache-Cache-0.03
Posted by DeWitt Clinton <de...@unto.net>.
On Sat, Mar 10, 2001 at 11:17:21AM -0800, Bill Moseley wrote:
> When you say successor to File::Cache does that means File::Cache
> will not be maintained as a separate module anymore?
There are no features in File::Cache that will not exist in
Cache::FileCache and Cache::SizeAwareFileCache. Actually, as far as I
know, the only old feature missing at all from the new code is the
ability to tell the cache not to physically remove expired objects.
There is a backdoor around this in 0.03, however, so if you need that
functionality, it is already possible.
I'm hoping to retire File::Cache soon unless I get another maintainer.
But it seems silly to have redundant efforts. The new code is much,
much, better.
> Have you though about making SharedMemoryCache flush to disk if it
> becomes full but before it's time to expire the data?
I've done a lot of thinking about a multi-layered cache
implementation. The API would be the same, but it would be clever
about using MemoryCache -> SharedMemoryCache -> FileCache to make read
access to data super efficient, and only persist outward on writes.
I'll mark that down as a potential 0.04 feature. Thanks, Bill!
-DeWitt
Re: [ANNOUNCE] Cache-Cache-0.03
Posted by Bill Moseley <mo...@hank.org>.
At 01:03 PM 03/10/01 -0500, DeWitt Clinton wrote:
>Summary:
>
> Perl Cache is the successor to the popular File::Cache and
> IPC::Cache perl libraries. This project unifies those modules under
> the generic Cache::Cache interface and implements Cache::FileCache,
> Cache::MemoryCache, Cache::SharedMemoryCache, and
> Cache::SizeAwareFileCache.
When you say successor to File::Cache does that means File::Cache will not
be maintained as a separate module anymore?
Have you though about making SharedMemoryCache flush to disk if it becomes
full but before it's time to expire the data?
Bill Moseley
mailto:moseley@hank.org