<!-- MHonArc v2.4.4 -->
<!--X-Subject: Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ?? -->
<!--X-From-R13: Hnqvz Fxnpuraxb <igNserrubyq.pebpbqvyr.bet> -->
<!--X-Date: Wed, 25 Mar 1998 05:23:38 +0000 -->
<!--X-Message-Id: 35185D49.6E6B1B72#freehold,crocodile.org -->
<!--X-Content-Type: text/plain -->
<!--X-Reference: Pine.PMDF.3.95.980323144315.543526539A-100000#nova,wright.edu -->
<!--X-Head-End-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<html>
<head>
<title>MUD-Dev message, Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</title>
<!-- meta name="robots" content="noindex,nofollow" -->
<link rev="made" href="mailto:vt#freehold,crocodile.org">
</head>
<body background="/backgrounds/paperback.gif" bgcolor="#ffffff"
text="#000000" link="#0000FF" alink="#FF0000" vlink="#006000">
<font size="+4" color="#804040">
<strong><em>MUD-Dev<br>mailing list archive</em></strong>
</font>
<br>
[ <a href="../">Other Periods</a>
| <a href="../../">Other mailing lists</a>
| <a href="/search.php3">Search</a>
]
<br clear=all><hr>
<!--X-Body-Begin-->
<!--X-User-Header-->
<!--X-User-Header-End-->
<!--X-TopPNI-->
Date:
[ <a href="msg00883.html">Previous</a>
| <a href="msg00885.html">Next</a>
]
Thread:
[ <a href="msg00852.html">Previous</a>
| <a href="msg00885.html">Next</a>
]
Index:
[ <A HREF="author.html#00884">Author</A>
| <A HREF="#00884">Date</A>
| <A HREF="thread.html#00884">Thread</A>
]
<!--X-TopPNI-End-->
<!--X-MsgBody-->
<!--X-Subject-Header-Begin-->
<H1>Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</H1>
<HR>
<!--X-Subject-Header-End-->
<!--X-Head-of-Message-->
<UL>
<LI><em>To</em>: <A HREF="mailto:mud-dev#null,net">mud-dev#null,net</A></LI>
<LI><em>Subject</em>: Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</LI>
<LI><em>From</em>: Vadim Tkachenko <<A HREF="mailto:vt#freehold,crocodile.org">vt#freehold,crocodile.org</A>></LI>
<LI><em>Date</em>: Tue, 24 Mar 1998 19:26:33 -0600</LI>
<LI><em>Sender</em>: <A HREF="mailto:vt#freehold,crocodile.org">vt#freehold,crocodile.org</A></LI>
</UL>
<!--X-Head-of-Message-End-->
<!--X-Head-Body-Sep-Begin-->
<HR>
<!--X-Head-Body-Sep-End-->
<!--X-Body-of-Message-->
<PRE>
s001gmu#nova,wright.edu wrote:
>
> On Sun, 22 Mar 1998, Matt Chatterley wrote:
>
> > On Sun, 22 Mar 1998, Chris Gray wrote:
> > > [Ben Greear:]
> >
> > [Snip]
> >
> > > :Also, as a java server, I don't think I can do a select on incomming
> > > :data. I think a thread for every player is a bit much...any suggestions
> > > :here?
> > >
> > > I have just started into the socket programming stuff of the current Java
> > > book I'm reading, but I just went and did some scanning. The technique
> > > he suggests for a server is to create some fixed number of threads, and
> > > re-use those threads throughout the lifetime of the server. He says that
> > > some Java implementations do not garbage collect threads at all, so having
> > > one per connection can result in an eventual crash due to lack of memory.
> > > Ick. Given the lack of a 'select' or 'poll' method in Java, the choices
> > > are quite limited. Double ick.
>
> [...]
>
> > Reusing threads is probably desirable, by the way, especially if less work
> > will be done to re-use an existant thread than to create a new one, and
> > not hard to do.
>
> As I understand it, it is usualy a LOT less work to reuse a thread that to
> destroy/create a new one.
>
> > Consider a model where you have a resizeable array (see the Vector class)
> > of Threads. You also maintain a list of available threads so you do not
> > have to recalulate it, and follow a procedure akin to:
> >
> > New connection is made to the server:
> > Check list of available threads.
> > If null: extend the Vector and add a new thread to handle the
> > connection.
> > If not null: take the 'top' thread and re-assign it.
> >
> > A connection closes:
> > Add that thread to the list of available threads.
> > Suspend and 'reset' the thread.
> >
> > Seems interesting anyway. :)
>
> This is very similar to a discussion we had about multi-threading event
> drivers. You might also consider, to reduce the number of creates and/or
> unused threads at the end of your array, a pool approach, with a min/max
> available setting. Something like so:
>
> You create the pool (array, call it what you will), with min/max avail set
> to 2/5. It starts with 5 avail (all unused). One person connects. no
> problem. Then 3 more connect. Now we have 4 in use, 1 avail, so the pool
> adds a new thread, taking the total count up to 6, 4 in use, 2 avail.
> lets say everyone then logs out. The pool has 6 avail, so it deletes
> one, to maintain the max avail at 5. This scheme works well, as long as
> you don't change the number of threads in use too radically. Constant,
> radical changes in number will prolly just add overhead to a simpler
> scheme, but as long as it fluctuates within the range you specify, it
> shan't create or destroy any threads.
>
> I liked the model, but haven't adopted it for my event driver. I want to
> run some tests with a static pool first, and see if I really do need a
> dynamic pool.
Once again, for those interested there is the implementation of two
pairs:
Packet/PacketSwitcher
Channel/ChannelSwitcher.
Implement the minSpare/maxSpare concept, with the addition: maxRunning -
I run into it when I needed to support the evaluation copy with a limit
of 2 concurrent connections :-))
Packet and Channel are the resources to share, just as an example -
database connection with autocommit is a Packet, database connection
which you need to commit/rollback manually is a Channel.
Switcher, respectively, is an object which maintains the proper number
of available resources in according to guidelines.
> -Greg
--
Still alive and smile stays on,
Vadim Tkachenko <vt#freehold,crocodile.org>
--
UNIX _is_ user friendly, he's just very picky about who his friends are
</PRE>
<!--X-Body-of-Message-End-->
<!--X-MsgBody-End-->
<!--X-Follow-Ups-->
<HR>
<!--X-Follow-Ups-End-->
<!--X-References-->
<UL><LI><STRONG>References</STRONG>:
<UL>
<LI><STRONG><A NAME="00852" HREF="msg00852.html">World Persistence, flat files v/s DB v/s ??</A></STRONG>
<UL><LI><EM>From:</EM> s001gmu#nova,wright.edu</LI></UL></LI>
</UL></LI></UL>
<!--X-References-End-->
<!--X-BotPNI-->
<UL>
<LI>Prev by Date:
<STRONG><A HREF="msg00883.html">Re: [MUD-Dev] Describe Concept</A></STRONG>
</LI>
<LI>Next by Date:
<STRONG><A HREF="msg00885.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></STRONG>
</LI>
<LI>Prev by thread:
<STRONG><A HREF="msg00852.html">World Persistence, flat files v/s DB v/s ??</A></STRONG>
</LI>
<LI>Next by thread:
<STRONG><A HREF="msg00885.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></STRONG>
</LI>
<LI>Index(es):
<UL>
<LI><A HREF="index.html#00884"><STRONG>Date</STRONG></A></LI>
<LI><A HREF="thread.html#00884"><STRONG>Thread</STRONG></A></LI>
</UL>
</LI>
</UL>
<!--X-BotPNI-End-->
<!--X-User-Footer-->
<!--X-User-Footer-End-->
<ul><li>Thread context:
<BLOCKQUOTE><UL>
<LI><strong><A NAME="00819" HREF="msg00819.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Chris Gray <a href="mailto:cg#ami-cg,GraySage.Edmonton.AB.CA">cg#ami-cg,GraySage.Edmonton.AB.CA</a>, Sun 22 Mar 1998, 18:21 GMT
<UL>
<LI><strong><A NAME="00822" HREF="msg00822.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Greg Munt <a href="mailto:greg#uni-corn,demon.co.uk">greg#uni-corn,demon.co.uk</a>, Sun 22 Mar 1998, 19:02 GMT
</LI>
<LI><strong><A NAME="00823" HREF="msg00823.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Matt Chatterley <a href="mailto:matt#mpc,dyn.ml.org">matt#mpc,dyn.ml.org</a>, Sun 22 Mar 1998, 19:19 GMT
<UL>
<LI><strong><A NAME="00852" HREF="msg00852.html">World Persistence, flat files v/s DB v/s ??</A></strong>,
s001gmu <a href="mailto:s001gmu#nova,wright.edu">s001gmu#nova,wright.edu</a>, Mon 23 Mar 1998, 19:51 GMT
<UL>
<LI><strong><A NAME="00884" HREF="msg00884.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Vadim Tkachenko <a href="mailto:vt#freehold,crocodile.org">vt#freehold,crocodile.org</a>, Wed 25 Mar 1998, 05:23 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00885" HREF="msg00885.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Vadim Tkachenko <a href="mailto:vt#freehold,crocodile.org">vt#freehold,crocodile.org</a>, Wed 25 Mar 1998, 05:26 GMT
<UL>
<LI><strong><A NAME="00894" HREF="msg00894.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Matt Chatterley <a href="mailto:matt#mpc,dyn.ml.org">matt#mpc,dyn.ml.org</a>, Wed 25 Mar 1998, 08:47 GMT
<UL>
<LI><strong><A NAME="00899" HREF="msg00899.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Vadim Tkachenko <a href="mailto:vt#freehold,crocodile.org">vt#freehold,crocodile.org</a>, Thu 26 Mar 1998, 01:59 GMT
<UL>
<LI><strong><A NAME="00904" HREF="msg00904.html">Re: [MUD-Dev] World Persistence, flat files v/s DB v/s ??</A></strong>,
Joel Dillon <a href="mailto:emily#cornholio,new.ox.ac.uk">emily#cornholio,new.ox.ac.uk</a>, Thu 26 Mar 1998, 15:52 GMT
</LI>
</UL>
</LI>
</UL>
</LI>
</UL>
</LI>
</UL>
</LI>
</UL>
</LI>
</UL></BLOCKQUOTE>
</ul>
<hr>
<center>
[ <a href="../">Other Periods</a>
| <a href="../../">Other mailing lists</a>
| <a href="/search.php3">Search</a>
]
</center>
<hr>
</body>
</html>
