DATABASE

Selecting a Database:
=====================

Gold makes use of a database for transactions and data persistence.
Three databases have been tested for use with Gold thus far: PostgreSQL,
MySQL and SQLite. Postgres and MySQL are external databases which run in a
distinct (possibly remote) process and communicate over sockets. These
databases must be separately installed, configured and started.
SQLite is an embedded database bundled with the Gold source code with SQL
queries being performed within the goldd process itself through library calls.
The following information may help you make a choice of databases to use.
    
  o PostgreSQL
    ----------

    PostgreSQL is an open source database. Gold requires Postgres 7.2 or higher
    (7.1 can probably be used but generates warnings from the DBD::Pg module).
    The PostgreSQL database has been thoroughly tested in production with Gold
    and all Gold functionality is available since it was developed using the
    PostgreSQL database. Postgres supports multiple connections so Gold is
    configured to be a forking server when using PostgreSQL.

  o MySQL
    -----

    MySQL is an open source database. Gold requires MySQL 4.0.6 or higher.
    (Prior versions did not support UNION which is used by Gold in time travel.
    It is possible to use 4.0 with a minor code tweak to the OFFSET line in
    Database.pm)

    MySQL 4.1 is required in order to have support for the (undocumented)
    Transaction Undo and Redo functionality since subqueries were not supported
    until this version.

  o SQLite
    ------

    SQLite is an open source embedded database bundled with Gold. It does
    not require any configuration and reads and writes from a file.
    Initial testing has shown Gold to perform at least as fast as PostgreSQL
    for small databases. 

    Due to the lack of "ALTER TABLE" functionality, Gold objects cannot be
    customized after installation. It appears that this functionality is likely
    to be forthcoming in a future release of SQLite.

    Since SQLite supports only a single connection, Gold is not configured to
    be a forking server when using SQLite. This should probably not be an issue
    for small to medium sized clusters.

    Due to a lack of support for multi-column IN clauses, the (undocumented)
    Transaction Undo and Redo functions are not available.