Hello Arkin,
Thanks for your most helpful advice.
cheers,
Parikshit
_____________________________________________________________________________________________________________
Parikshit Pol
Systems Executive
KPIT System Ltd.
6,Mayur Colony,
Karve Road,
Pune-411029
e-mail :< [EMAIL PROTECTED] >
Phone : 91-020-5468654 ext. - 212
_______________________________________________________________________________________________
-----Original Message-----
From: Assaf Arkin [SMTP:[EMAIL PROTECTED]]
Sent: Tuesday, December 28, 1999 1:52 AM
To: [EMAIL PROTECTED]
Subject: Re: Number of connections in Connection pool.
Let's start with the 200 number. If your server cannot start with 200
connections, it can't grow to 200 connections over time.
I'm running the Linux JVM with PostgreSQL. Beyond 150 database
connections my machine simply dies from process overload. Of course your
number may vary, but there's an upper limit on how many open connections
your machine can keep. If you'r running the EJB server and database on
the same machine this might be a thread/process limitation. If you're
running on two separate machines, this might be a TCP/IP stack
limitation. 200 db connections means 200 open sockets, which might be
too much to handle.
Keep in mind, the whole point of TPM (transaction processing monitor),
is to get N beans talking to 1 database through M connections, where N >
M. I'm running tests with 1000 beans talking to 1 database over 20
connections.
If all your database can hold are 150 connections, you can still have
1000 beans talking to it.
> 2. I specify the inital capacity as 20(saving server's resources), max
as 500 and capacity increment as 20. But in turn I sacrifice performance
as I have to make connections more frequently.
Not really. Let's say you start with 20 connections and at peak time
your server requires between 400 to 500 connections. The server will
increase the pool size to 500 and will keep it at 500 as long as you
need so many connections. Once peak time is off, the server will start
gradually releasing connections until it goes back to 20. But you will
always have more connections in the pool than you actually need.
Think of the following parameters. Every connection is pooled, so it
gets used, then goes to the pool, then is reused. No new connection is
created if a pooled connection is available.
The pool size reflects the demand over a period of time (e.g. a minute,
five minutes), so if during that time demand is between 400 to 500
(changing every second) the pool will stay fixed at 500.
The pool starts at a given size but will grow dynamically. It will
shrink dynamically gradually only if connections are not used (e.g.
during the night).
Whether you start with 20 or 300, during peak performance you get the
same number of connection creations. But you place less load on the
server.
arkin
> What is the best way. Any comments/debate will be appreciated.
> Cheers,
> Parikshit
>
________________________________________________________________________
_____________________________________
> Parikshit Pol
> Systems Executive
> KPIT System Ltd.
> 6,Mayur Colony,
> Karve Road,
> Pune-411029
> e-mail :< [EMAIL PROTECTED] >
> Phone : 91-020-5468654 ext. - 212
>
________________________________________________________________________
_______________________
>
> -----Original Message-----
> From: Assaf Arkin [SMTP:[EMAIL PROTECTED]]
> Sent: Friday, December 24, 1999 1:33 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Number of connections in Connection pool.
>
> << File: ATT00000.txt; charset = windows-1252 >>
>
>
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