Re: [basedb-devel] intermittent hibernate errors when using BASE API

2008-08-05 Thread Bob MacCallum

Hi Nicklas,

I'll double check but I think we're sharing one DbControl across the whole
webapp, so that will be the first place to look.

Thanks for the hint.  Will post back when I have a solution.

cheers,
Bob.


Nicklas Nordborg writes:
  Bob MacCallum wrote:
   Quick follow up to:
   http://www.mail-archive.com/basedb-devel@lists.sourceforge.net/msg00316.html
   
   The problem seems to be triggered by concurrent access to our BASE-based 
   web
   application (for example, me and googlebot).
   
   That doesn't bring me any closer to understanding what exactly is going on,
   but I thought I would share.
   
   I wonder if similar stacktraces occur on a busy multi-user BASE server?
   
  
  Are you sharing objects (eg. an ItemQuery, DbControl, etc.) between 
  different threads? I think the problem can be caused by multiple threads 
  that are accessing the same non-threadsafe object at the same time.
  
  /Nicklas
  
  
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-- 
Bob MacCallum | VectorBase Developer | Kafatos/Christophides Groups |
Division of Cell and Molecular Biology | Imperial College London |
Phone +442075941945 | Email [EMAIL PROTECTED]

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Re: [basedb-devel] intermittent hibernate errors when using BASE API

2008-08-05 Thread Nicklas Nordborg
Bob MacCallum wrote:
 Hi Nicklas,
 
 I'll double check but I think we're sharing one DbControl across the whole
 webapp, so that will be the first place to look.

This will definitely give you a lot of problems since a DbControl is not 
thread-safe. You may also run into memory problems since every item that 
  has been loaded from the database will be stored in a cache. If you 
use one DbControl for everything you will end up with the entire 
database as  Java objects in memory.

In other words, every request to the web application needs it's own 
DbControl.

/Nicklas


 
 Thanks for the hint.  Will post back when I have a solution.
 
 cheers,
 Bob.
 
 
 Nicklas Nordborg writes:
   Bob MacCallum wrote:
Quick follow up to:

 http://www.mail-archive.com/basedb-devel@lists.sourceforge.net/msg00316.html

The problem seems to be triggered by concurrent access to our BASE-based 
 web
application (for example, me and googlebot).

That doesn't bring me any closer to understanding what exactly is going 
 on,
but I thought I would share.

I wonder if similar stacktraces occur on a busy multi-user BASE server?

   
   Are you sharing objects (eg. an ItemQuery, DbControl, etc.) between 
   different threads? I think the problem can be caused by multiple threads 
   that are accessing the same non-threadsafe object at the same time.
   
   /Nicklas
   
   
   -
   This SF.Net email is sponsored by the Moblin Your Move Developer's 
 challenge
   Build the coolest Linux based applications with Moblin SDK  win great 
 prizes
   Grand prize is a trip for two to an Open Source event anywhere in the world
   http://moblin-contest.org/redirect.php?banner_id=100url=/
   ___
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   https://lists.sourceforge.net/lists/listinfo/basedb-devel
 


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Re: [basedb-devel] intermittent hibernate errors when using BASE API

2008-08-04 Thread Nicklas Nordborg
Bob MacCallum wrote:
 Quick follow up to:
 http://www.mail-archive.com/basedb-devel@lists.sourceforge.net/msg00316.html
 
 The problem seems to be triggered by concurrent access to our BASE-based web
 application (for example, me and googlebot).
 
 That doesn't bring me any closer to understanding what exactly is going on,
 but I thought I would share.
 
 I wonder if similar stacktraces occur on a busy multi-user BASE server?
 

Are you sharing objects (eg. an ItemQuery, DbControl, etc.) between 
different threads? I think the problem can be caused by multiple threads 
that are accessing the same non-threadsafe object at the same time.

/Nicklas


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Build the coolest Linux based applications with Moblin SDK  win great prizes
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