You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@tomcat.apache.org by "Caldarale, Charles R" <Ch...@unisys.com> on 2008/09/18 05:26:16 UTC
RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
keepincreasing....
> From: sinoea kaabi [mailto:sinoea@msn.com]
> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active
> connections keepincreasing....
>
> I could accept the fact that we should create new objects of Dao's,
> but for getting a datasource or connection it should make sense
> to have a utility class with static methods.
Absolutely - Johnny K's suggestion of doing a new every time is utter nonsense.
> So is a connection a thread-safe object or not?
No, a connection is not thread-safe: it is designed to be be used by only one thread at a time. If you have multiple threads accessing a connection object *simultaneously*, you will have problems. On the other hand, connection managers (e.g., the commons-dbcp code) are thread-safe; multiple threads may call one simultaneously to acquire connection objects, and each thread is guaranteed to be given a separate object.
- Chuck
THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
Posted by Johnny Kewl <jo...@kewlstuff.co.za>.
----- Original Message -----
From: "sinoea kaabi" <si...@msn.com>
To: "Tomcat Users List" <us...@tomcat.apache.org>
Sent: Thursday, September 18, 2008 1:24 PM
Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
keepincreasing....
Struts datasource usage is deprecated, they encourage users not to try their
datasource configuration in the xml.
Instead I was advised to manually configure JNDI connection pooling with
Struts.
------------
Ah... the thlot pickens....
---------------------------------------------------------------------------
HARBOR : http://www.kewlstuff.co.za/index.htm
The most powerful application server on earth.
The only real POJO Application Server.
See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm
---------------------------------------------------------------------------
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
keepincreasing....
Posted by sinoea kaabi <si...@msn.com>.
Struts datasource usage is deprecated, they encourage users not to try their
datasource configuration in the xml.
Instead I was advised to manually configure JNDI connection pooling with Struts.
> From: john@kewlstuff.co.za
> To: users@tomcat.apache.org
> Subject: Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
> Date: Thu, 18 Sep 2008 12:04:11 +0200
>
>
> ----- Original Message -----
> From: "Caldarale, Charles R" <Ch...@unisys.com>
> To: "Tomcat Users List" <us...@tomcat.apache.org>
> Sent: Thursday, September 18, 2008 5:26 AM
> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
> keepincreasing....
>
>
> > From: sinoea kaabi [mailto:sinoea@msn.com]
> > Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active
> > connections keepincreasing....
> >
> > I could accept the fact that we should create new objects of Dao's,
> > but for getting a datasource or connection it should make sense
> > to have a utility class with static methods.
>
> Absolutely - Johnny K's suggestion of doing a new every time is utter
> nonsense.
>
> ---------------
>
> I eat humble pie.... you right... completely off track...
>
> One of the problems is that I'm not thinking framework... and sinoea is in
> one.
> Also not having used DBCP I'm at a disadvantage here... maybe should just
> shut the hell up...
>
> As I see it... sinoea is creating a singleton... to hold that data source...
> he has to because the control servlet is inside a framework, so he is
> "holding" a pool from the fridge of the framework...
>
> So... struts people... just help this guy...
> Does struts have a better built in way to manage the pool... so he can just
> get the reference to it?
> If not... what is standard practice for using a "third party" pool in the
> struts framework...
>
> He's into holding stuff in statics... because he is trying to keep a single
> instance of the pool available to all the rest of his action objects...
>
> Thats what he's asking... what is the right way to do that in struts....
> like maybe its standard practice to hold DHCP in a servlet context
> attribute... or maybe struts has a really clever way of doing that for
> you... thats the question?
>
> ... my suggestions do suck... what is the right way in struts to hold that
> 3rd party pool dish out references where they needed ?
>
> ---------------------------------------------------------------------------
> HARBOR : http://www.kewlstuff.co.za/index.htm
> The most powerful application server on earth.
> The only real POJO Application Server.
> See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm
> ---------------------------------------------------------------------------
>
>
> ---------------------------------------------------------------------
> To start a new topic, e-mail: users@tomcat.apache.org
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
_________________________________________________________________
Make a mini you and download it into Windows Live Messenger
http://clk.atdmt.com/UKM/go/111354029/direct/01/
Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
Posted by Johnny Kewl <jo...@kewlstuff.co.za>.
----- Original Message -----
From: "Caldarale, Charles R" <Ch...@unisys.com>
To: "Tomcat Users List" <us...@tomcat.apache.org>
Sent: Thursday, September 18, 2008 5:26 AM
Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
keepincreasing....
> From: sinoea kaabi [mailto:sinoea@msn.com]
> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active
> connections keepincreasing....
>
> I could accept the fact that we should create new objects of Dao's,
> but for getting a datasource or connection it should make sense
> to have a utility class with static methods.
Absolutely - Johnny K's suggestion of doing a new every time is utter
nonsense.
---------------
I eat humble pie.... you right... completely off track...
One of the problems is that I'm not thinking framework... and sinoea is in
one.
Also not having used DBCP I'm at a disadvantage here... maybe should just
shut the hell up...
As I see it... sinoea is creating a singleton... to hold that data source...
he has to because the control servlet is inside a framework, so he is
"holding" a pool from the fridge of the framework...
So... struts people... just help this guy...
Does struts have a better built in way to manage the pool... so he can just
get the reference to it?
If not... what is standard practice for using a "third party" pool in the
struts framework...
He's into holding stuff in statics... because he is trying to keep a single
instance of the pool available to all the rest of his action objects...
Thats what he's asking... what is the right way to do that in struts....
like maybe its standard practice to hold DHCP in a servlet context
attribute... or maybe struts has a really clever way of doing that for
you... thats the question?
... my suggestions do suck... what is the right way in struts to hold that
3rd party pool dish out references where they needed ?
---------------------------------------------------------------------------
HARBOR : http://www.kewlstuff.co.za/index.htm
The most powerful application server on earth.
The only real POJO Application Server.
See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm
---------------------------------------------------------------------------
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
Posted by David Smith <dn...@cornell.edu>.
The datasource object is threadsafe and a prime example of the factory
pattern. In my designs, I tend to retrieve a reference to it early on
and then store it somewhere convenient for the life of the request.
Then each db access method get's a connection, uses it and closes it
before returning. I'm also a fan of the architecture Chris Shultz
posted (only one try catch w/ try/catches in the finally block for each
db object):
try {
// get connection
// do something
} catch ( exception e ) {
// log or otherwise handle the error
// I tend to wrap the exception and rethrow it in a higher level
exception
} finally {
try { resultset.close() ; } catch (exception e1) {}
try { statement.close() ; } catch (exception e2) {}
try { connection.close() ; } catch (exception e3) {}
}
return ...
Obviously I'm being really terse here, but I think you see the general
idea. As an overall pattern, I tend to encapsulate db access in a small
number of methods like the one above, leaving the remainder of the
project free to work with beans/arrays/hashtables/whatever.
I also like Chris' ideas regarding how to diagnose the issue -- drop the
pool size down really small and see if the pool get's exhausted. What
you are seeing may be some wierd artifact of how DBCP manages it's
connection pool.
--David
sinoea kaabi wrote:
> Right, since I seem to be the only alien having this problem I would
> be happy to know how you write jdbc classes and (if any) a datasource manager.
>
> Do you create a separate class for retrieving connections or datasources.
> Are the methods static.
>
> How do your dao's code look like?
> For example when using a connection, statement, resultset. How and where do you close them, and do you return values afterwards.
>
> Do you use the factory pattern?
>
> Any code examples, step by step guide of something that
> works would be very helpful.
>
>
> Basically, a great step by step tutorial would be more helpful than trying to spot my problem as
> everyone seems to have a different opinion from the other.
> Frankly speaking, I believe there is no sufficient and a spot-on-clear documentation
> of what thread safe servlet containers really mean and the usage of static methods
> on these servlet containers.
> The current documentation can be understood in many different ways.
>
> What interests me more about this thread is that many people suggested to avoid using
> static methods in web applications.
>
> Avoiding static methods for DAO's is understandable, but avoiding static methods for retrieving a datasource
> seems strange.
>
> I have seen millions (if not zillions) code examples on the net where static methods are used for retrieving
> datasources.
>
> So I would be happy to see how others write code without static methods.
>
>
> Thanks,
> Sinoea
>
>
>> From: Chuck.Caldarale@unisys.com
>> To: users@tomcat.apache.org
>> Date: Wed, 17 Sep 2008 22:26:16 -0500
>> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
>>
>>
>>> From: sinoea kaabi [mailto:sinoea@msn.com]
>>> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active
>>> connections keepincreasing....
>>>
>>> I could accept the fact that we should create new objects of Dao's,
>>> but for getting a datasource or connection it should make sense
>>> to have a utility class with static methods.
>>>
>> Absolutely - Johnny K's suggestion of doing a new every time is utter nonsense.
>>
>>
>>> So is a connection a thread-safe object or not?
>>>
>> No, a connection is not thread-safe: it is designed to be be used by only one thread at a time. If you have multiple threads accessing a connection object *simultaneously*, you will have problems. On the other hand, connection managers (e.g., the commons-dbcp code) are thread-safe; multiple threads may call one simultaneously to acquire connection objects, and each thread is guaranteed to be given a separate object.
>>
>> - Chuck
>>
>>
>> THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.
>>
>> ---------------------------------------------------------------------
>> To start a new topic, e-mail: users@tomcat.apache.org
>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>>
>
> _________________________________________________________________
> Make a mini you and download it into Windows Live Messenger
> http://clk.atdmt.com/UKM/go/111354029/direct/01/
> ---------------------------------------------------------------------
> To start a new topic, e-mail: users@tomcat.apache.org
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
RE: Tomcat 5.5, JNDI Connection Pooling, Active connections
keepincreasing....
Posted by sinoea kaabi <si...@msn.com>.
Right, since I seem to be the only alien having this problem I would
be happy to know how you write jdbc classes and (if any) a datasource manager.
Do you create a separate class for retrieving connections or datasources.
Are the methods static.
How do your dao's code look like?
For example when using a connection, statement, resultset. How and where do you close them, and do you return values afterwards.
Do you use the factory pattern?
Any code examples, step by step guide of something that
works would be very helpful.
Basically, a great step by step tutorial would be more helpful than trying to spot my problem as
everyone seems to have a different opinion from the other.
Frankly speaking, I believe there is no sufficient and a spot-on-clear documentation
of what thread safe servlet containers really mean and the usage of static methods
on these servlet containers.
The current documentation can be understood in many different ways.
What interests me more about this thread is that many people suggested to avoid using
static methods in web applications.
Avoiding static methods for DAO's is understandable, but avoiding static methods for retrieving a datasource
seems strange.
I have seen millions (if not zillions) code examples on the net where static methods are used for retrieving
datasources.
So I would be happy to see how others write code without static methods.
Thanks,
Sinoea
> From: Chuck.Caldarale@unisys.com
> To: users@tomcat.apache.org
> Date: Wed, 17 Sep 2008 22:26:16 -0500
> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections keepincreasing....
>
>> From: sinoea kaabi [mailto:sinoea@msn.com]
>> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active
>> connections keepincreasing....
>>
>> I could accept the fact that we should create new objects of Dao's,
>> but for getting a datasource or connection it should make sense
>> to have a utility class with static methods.
>
> Absolutely - Johnny K's suggestion of doing a new every time is utter nonsense.
>
>> So is a connection a thread-safe object or not?
>
> No, a connection is not thread-safe: it is designed to be be used by only one thread at a time. If you have multiple threads accessing a connection object *simultaneously*, you will have problems. On the other hand, connection managers (e.g., the commons-dbcp code) are thread-safe; multiple threads may call one simultaneously to acquire connection objects, and each thread is guaranteed to be given a separate object.
>
> - Chuck
>
>
> THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.
>
> ---------------------------------------------------------------------
> To start a new topic, e-mail: users@tomcat.apache.org
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
_________________________________________________________________
Make a mini you and download it into Windows Live Messenger
http://clk.atdmt.com/UKM/go/111354029/direct/01/
---------------------------------------------------------------------
To start a new topic, e-mail: users@tomcat.apache.org
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org