CXXXVIII. PostgreSQL Session Save Handler

Introduction

Note: This extension is not available on Windows platforms.

This module provides an additional session save handler for the session module using PostgreSQL as a storage system. A user-level session storage function may also be used - session_set_save_handler(), but this module is written in C and therefore could be twice as fast, compared to a session save handler written in PHP.

Session PgSQL is designed to scale any size of web sites and offers some advanced features:

session tables are created automatically

automatic session table vacuum

better garbage collection

multiple PostgreSQL servers support

automatic database server failover (switching)

automatic database server load balancing if there are multiple PostgreSQL servers.

short circuit UPDATE

Requirements

You need at least PHP >= 4.3.0, and PostgreSQL >=7.2.0 as database server. libpq that comes with PostgreSQL 7.2.0 or later (and header files to build) and libmm (and header files).

Installation

Short installation note:

Untar the tar.gz archive into php4/ext (Latest official releases can be found at SourceForge PHP Form Extension Project)
If the new directory is now called something like session_pgsql. You should name it to session_pgsql (except you only want to build it as self-contained php-module).
Run ./buildconf in php4
Run configure --with-session-pgsql (and your other options)
make; make install

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

PostgreSQL session save handler is still under development. Refer to the README file in the source distribution for configuration details.

Table definitions

Session table definition
CREATE TABLE php_session ( sess_id text, sess_name text, sess_data text, sess_created integer, sess_modified integer, sess_expire integer, sess_addr_created text, sess_addr_modified text, sess_counter integer, sess_error integer, sess_warning integer, sess_notice integer, sess_err_message text, sess_custom text ); CREATE INDEX php_session_idx ON php_session USING BTREE (sess_id);

Warning

If you use HASH for INDEX, you'll have a deadlock problem when the server load is very high. Even if it's unlikely to have a deadlock under normal operation, it can occur. Do not use HASH for INDEX.

You may change the session table as long as all fields are defined.

Application variables table definition
CREATE TABLE php_app_vars ( app_modified integer, app_name text, app_vars text );

Contact Information

I have at the moment not very much time to further develop this extension. I will implement more and more features in the near future.

If you have comments, bug fixes, enhancements or want to help developing this, you can drop me a mail at yohgaki@php.net. Any help is very welcome.

Table of Contents
session_pgsql_add_error -- Increments error counts and sets last error message
session_pgsql_get_error -- Returns number of errors and last error message
session_pgsql_get_field -- Get custom field value
session_pgsql_reset -- Reset connection to session database servers
session_pgsql_set_field -- Set custom field value
session_pgsql_status -- Get current save handler status