Location

Easing into PostgreSQL Hacking

User-defined functions are one of the easiest ways to get started hacking on the PostgreSQL codebase and produce something useful in a short time. Watch a whole new trivial feature get added with one, and learn how to step over some of the more common confusing parts of the codebase along the way.

PostgreSQL's user-defined function (UDF) mechanism is useful for all sorts of things. You can add your own custom C code to the database, for performance or extensibility reasons. You can expose database internals that you wouldn't otherwise be able to access. And it's a great way to get started hacking on PostgreSQL with quick results.

This talk leads you through a quick tour of creating a UDF that exposes a useful bit of information about how you're using the shared_buffers cache on your system. Consider it a "hello, world" for writing a PostgreSQL patch that adds a tiny feature as a function. You'll learn some tricks for how to find useful code to borrow too. Knowing where some simple examples are at is most of the battle when getting started here.

The material is based on several conversations about the most confusing PostgreSQL hacking basics with those completely new to that area, in hopes that you won't have to get stuck on the same things they did. You'll need a basic understanding of coding in C or similar languages to follow the examples, but not any previous exposure to the PostgreSQL code.

Location

We propose to add hypothetical (or virtual) indexes in order to offer both what-if querying and automatic index tuning.

Hypothetical indexes are simulated index structures created solely in the database catalog. This type of index has no physical extension and, therefore, cannot be used to answer actual queries. The main benefit is to provide a means for simulating how query execution plans would change if the hypothetical indexes were actually created in the database. This feature is quite useful for database tuners and DBAs.

Index selection tools, such as Microsoft's SQL Server Index Tuning Wizard, make use of hypothetical (or virtual) indexes in the database server to evaluate candidate index configurations.

We have made some server extensions to PostgreSQL 8.* to include the notion of hypothetical indexes in the system. We have introduced three new commands: create hypothetical index, drop hypothetical index and explain hypothetical.

After implementing the server extensions for hypothetical indexes, we could use it for future automatic indexing with PostgreSQL besides simples, yet useful, what-if queries.

Location

Case study of PostgreSQL in the Multicanal project of the brazilian bank Caixa Economica Federal

Case study of PostgreSQL in the project "Multicanal" of the brazilian government bank Caixa Economica Federal - the day-to-day activities, challenges, solutions proposed and approved, high availability and high performance in the world's unique Free Software case in this type of public institution.

Introduction to the "Multicanal" project, how it works, what it does and the importance for Caixa and the brazilian people. The inclusion of PostgreSQL and other Free and Open-Source Software on the project and Caixa at all. The role of 4Linux and Caixa in the project. Day-to-day challenges in the database administration. Database production and maintenance challenges. PostgreSQL tuning techniques involved in the systems. Tested and approved high availability techniques for PostgreSQL. Today's and future needs. Planned and achieved objectives.