Re: [WebMacro-user

Hi Lane,

Lane Sharman wrote:

Hi Nikolaos.

This is most disturbing to hear about.

Thank you for replying.

First, there is a known concurrency issue with WM in 2.0 and possibly
in prior releases. If you look at the mail thread dating back for 45
days, you will definitely see it.

I will take a look at that thread.

My concern is that the webmacro instance, shared, and the context, not
shared, is improperly orchestrated for concurrency. The webmacro
instance is local to WMServlet. You might consider synchronizing access
to this variable as a trial fix in your local calls below. This will
introduce some serialization of web processing but it might help to
verify the solution.

I will try this tip

One thing you might consider trying is to use a different
cache
handler. A few years ago, I wrote one and it is a part of the distro. I
have never had a problem using this cache handler.

Lane

Thank you !

--- Nikolaos Papadakis <[email protected]> wrote:

From: Nikolaos Papadakis <[email protected]>

Date: Sat, 18 Feb 2006 10:50:33 +0200

To: [email protected]

Subject: [WebMacro-user] [WebMacro-user

Hi all,

I am using webmacro to develop a web-based application.

Things seemed to work fine till yesterday. A customer complained that
he

managed to “see” the account of another customer when he logged-in
using

his own credentials (he send me a screen shot of the “view”).

By inspecting the log file I found that both users have been logged-in

at the same time (the second customer logged in 3 sec after the first

customer).

The system has more than 1000 customers but this inconvenience happened

for the first time yesterday (?).

It seems that different sessions have been mixed up.

The servlet includes a handle method and uses several other methods

(methods that write and read from a database).

All methods are defined in the same class (that extends WMServlet).

As far as I know servlets must not have instance variables (only local

variables -inside methods- to prevent data corruption and

inconsistencies). However in my servlet I use only one non local

variable (a Logger) and I don't think this is the cause of the problem.

As an attached file I send you a fragment of the before mentioned
servlet.

Can instance variables be defined in the case of a servlet that extends

WMServlet? (I mean is it safe? or its not a good practice without

keeping precautions?)

Do you have any idea what can have caused this inconvenience ?

Is the use of methods inside the servlet thread-safe ?

Please help!!!

Nikolaos Papadakis

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