DBIx/HA version 1.00

DBIx::HA is a High Availability module for DBI. It is implemented by overloading the DBI connect, prepare and execute methods and can be seamlessly used without code modification except for initialization.

DBIx::HA also works seamlessly with Apache::DBI when available, and ensures that cached database handles in the Apache::DBI module are properly released when failing over.

Features of DBIx::HA are:

multiple failovers Should a datasource become unavailable, queries are automatically sent to the next available datasource in a user-configured datasource stack. All subsequent queries continue to hit the failover server until reinitialized. This ensures that a failed datasource can be properly brought back online before it is put back in service.
timeouts Database calls are wrapped in user-configurable timeouts. Connect and execute timeouts are handled independently.
configurable retries Queries can be retried n times before a datasource is considered failed.
callback function A user-defined callback function can be called upon abnormal failure and disconnection from a datasource in order to clean locally cached handles and perform other housekeeping tasks.
inter-process automatic failover under mod_perl Failover can be triggered for a single process or a set of processes at the application level. Specifically designed for Apache's multi-process model, if one mod_perl process triggers a failover, it is propagated to all other mod_perl processes using the same database handle.

DBIx::HA was designed primarily for reliability and speed. Functionality that would compromise speed was not considered. This module has been tested extensively at very high loads in the Apache/mod_perl/Sybase environment.

INSTALLATION

To install this module type the following:

perl Makefile.PL
make
make install

DEPENDENCIES

This modules requires Perl >= 5.6.0.
It also requires DBI >= 1.49
Apache::DBI is recommended when using mod_perl (v1 only). If using Apache::DBI, version 0.89 or above is required.

WEBSITE AND SVN REPOSITORY

The DBIx::HA sourcecode is hosted on Google Code: http://code.google.com/p/perl-dbix-ha/

Please submit bug reports or feature improvements in at the site above. The SVN repository can likewise be accessed at: http://perl-dbix-ha.googlecode.com/svn/

COPYRIGHT AND LICENCE