Transaction Isolation Levels in PostgreSQL

Everyone has heard something about transaction isolation levels, but oddly enough, almost no one can clearly explain what it is any why it is important. At the same time, for many operations, it is critical to have a clear understanding of isolation levels and how they can affect the result. Indeed, if a customer has been paid twice and the developer has to pay back the losses, it won't seem unimportant. We'll discuss how to avoid such unpleasant situations.

Writing a User-defined datatype

Walk-through of extending PostgreSQL with a user-defined type. The journey begins from the basics, from creating simple domain types over existing types, and continues to implementing a full-blown datatype from scratch in C.

PostgreSQL's advanced index types, GiST, GIN, and SP-GiST, are covered in enough detail to give an understanding of what each of them is good for. Support functions for each of them are shown for the example 'color' datatype.

Migration from Oracle to PostgreSQL using an automatic converter

In the report, we want to talk about the experience of migrating one large system from Oracle to PostgreSQL. The system itself was built on the PHP + Oracle stack; its distinguishing feature was that all business logic was implemented in PL / SQL code. In a DBMS, there are more than 3000 packages with 4-10 functions (procedures) in each. In PHP - more than 10,000 forms with inserts of anonymous blocks used to receive data, process and save results in Oracle.

To solve this extremely voluminous work, we took ANTLR4 (a powerful parser generator for reading, processing, executing, or translating structured text), PL/SQL grammar, and created an automatic converter that allows you to convert all objects in the schema and our system from Oracle to working code for PostgreSQL.

Database backup with pg_probackup

pg_probackup is a flexible tool that allows choosing the backup strategy depending on the write load of the PostgreSQL cluster, as well as offers a number of other features that can facilitate this vital aspect of database maintenance. In this tutorial, we will see how to apply this tool in practice.