PGConf.SPB 2023

A talk on how regular™ indexes work in PostgreSQL. The talk will be extremely useful for those who are starting to work with databases, and for those who have worked with them but have forgotten. If the talk hits the golden picks of "must-see onboarding developer", then the goal is achieved.
We will tackle the following subtopics:
- How an index can speed up search;
- Should we index WHERE conditions;
- Should we index ORDER BY statements;
- Should we index foreign keys;
- What to do if search pre-assumes multiple conditions;
- Which column order should be specified in an index;
- Cases when index causes a slow-down and how to reduce its impact on the app.

As you probably know, PostgreSQL has a number of distinct features compared to other DBMSs. For example, Postgres can process and store many different types of data. However, you need to know something about them before using them. In this talk, we will find the reason why queries to the table begin to slow down (and autovacuum / vacuum has nothing to do with it) and try to speed up such queries. I will tell you how integer data types work in PostgreSQL and touch on the topic of speeding up such queries. And finally, let's talk about how to make your data in tables take up less space while increasing the speed of queries to this data.

Backup is still a stumbling block when migrating to PostgreSQL from other DBMSs. Its size directly depends on your experience and knowledge about the types of backups in PostgreSQL. In this talk, I will tell you about different types of backups, their pros and cons, and scenarios for using each type.

Recently, one of the most common migration methods has become migration using the free ora2pg tool. However, many note the extremely low performance of this tool, especially when it comes to databases of 1 Terabyte and above. This presentation describes how to significantly speed up database migration using oracle_fdw alone or in combination with ora2pg.