Book Image

PostgreSQL Server Programming

Book Image

PostgreSQL Server Programming

Overview of this book

Learn how to work with PostgreSQL as if you spent the last decade working on it. PostgreSQL is capable of providing you with all of the options that you have in your favourite development language and then extending that right on to the database server. With this knowledge in hand, you will be able to respond to the current demand for advanced PostgreSQL skills in a lucrative and booming market."PostgreSQL Server Programming" will show you that PostgreSQL is so much more than a database server. In fact, it could even be seen as an application development framework, with the added bonuses of transaction support, massive data storage, journaling, recovery and a host of other features that the PostgreSQL engine provides. This book will take you from learning the basic parts of a PostgreSQL function, then writing them in languages other than the built-in PL/PgSQL. You will see how to create libraries of useful code, group them into even more useful components, and distribute them to the community. You will see how to extract data from a multitude of foreign data sources, and then extend PostgreSQL to do it natively. And you can do all of this in a nifty debugging interface that will allow you to do it efficiently and with reliability.
Table of Contents (17 chapters)
PostgreSQL Server Programming
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Basic guidelines for writing C code


After having written our first function, let's look at some of the basic coding guidelines for PostgreSQL backend coding.

Memory allocation

One of the places you have to be extra careful when writing C code in general is memory management. For any non-trivial C program you have to carefully design and implement your programs so that all your allocated memory is freed when you are done with it, or else you will "leak memory" and will probably run out of memory at some point.

As this is also a common concern for PostgreSQL it has it's own solution for it—Memory Contexts. Let's take a deeper dive into them.

Use palloc() and pfree()

Most PostgreSQL memory allocations are done using PostgreSQL's memory allocation function palloc() and not standard C malloc(). What makes palloc() special, is that it allocates the memory in current context and the whole memory is freed in one go when the context is destroyed. For example, the transaction context—which is the current...