Thread Safety

From KallestadWiki

The big question of whether to create a database connection pool based on POE or based on Perl threads comes down to one question:

1. Will end users be able to use it easily?

Certainly POE will require POE to be installed. POE is a module though, and enabling Perl threading requires that Perl be compiled in such a manner that it will support threads. Score 1 for POE. It's easier at this point.

Another deciding factor is MySQL. Quoting from the DBD::mysql POD

 The multithreading capabilities of DBD::mysql depend completely on the underlying C libraries: The modules are working with handle
 data only, no global variables are accessed or (to the best of my knowledge) thread unsafe functions are called. Thus DBD::mysql is
 believed to be completely thread safe, if the C libraries are thread safe and you don't share handles among threads.

 The obvious question is: Are the C libraries thread safe? In the case of MySQL the answer is "mostly" and, in theory, you should be
 able to get a "yes", if the C library is compiled for being thread safe (By default it isn't.) by passing the option 
 -with-thread-safe-client to configure. See the section on How to make a threadsafe client in the manual.

This is another score for a POE based solution. Most people do not compile their own MySQL version, and requiring custom compile options for both Perl and MySQL for basic KDF functionality is not something I want to do.

Database Connection Pooling Topics

• Database Pool
• Development Concerns
  • Thread Safety
  • POE
  • POE DB Modules
• Design Overview

Kallestad Development Framework Topics

• KDF Home
• Project Overview
  • Peripheral Objectives
• Technical Information
  • Back End
    • Complex Objects
    • Abstract Elements
    • SQL API
  • Front End
  • Database Pool
• Licensing