Re: [fpc-devel] FCL Thread-safety

[Nikolai Zhubr]

27.01.2010 15:30, Leonardo M. Ramé:
I can confirm FCL-XML is thread safe, at least in FPC 2.5.1, also
Zeos as far as you create a new connection to the database inside
each thread.

I'm using both libraries in a multithreaded daemon that receives an
XML file via socket, then connects to a Postgres database using
Zeos.
Thank you very much! That is very similar to what I'll be doing, except 
that I just dont use XML. Yes, I'll create 1 connector per thread of course.
The only concern then is how to ensure that thread-safety is not 
(ocasionally) destroyed with some future FCL and/or zeoslib versions. It 
somehow seems quite uneasy to design a simple and yet reliable 
regression-test for automated testing. On the other hand, verifying it 
all by hand is also not what I'd be dreaming of.

Thank you!

Nikolai

While developing this, the first issue was many database deadlocks,
and transaction problems caused because I was sharing a global
database connection, the solution was creating an instance of the
database connector in the Thread constructor, and destroy it in the
Thread destructror. Regarding the FCL-XML, I was using an old version
based on AVLTree, and found it have many problems when working within
threads, all of them solved after upgrading to the latest version.


Leonardo M. Ramé http://leonardorame.blogspot.com

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