PgConf.Russia 2019

Wide usage of Common Table Expression queries considered as a core paradigm for implementing the Business Logic for high loaded web applications development based on PostgreSQL functions.

IIn the world of programming, the creation of source code for databases "procedural extensions" is something solitary. Most DBMS offers procedural languages and "stored procedures" to create procedural extensions. In Postgres the number of supported procedural languages has already exceeded a dozen.

Traditionally, stored procedures have many applications: it is difficult to resist the attraction to perform a data operation directly in the storage, especially in the Enterprise development. This approach quickly leads to the spreading of the business logic and dramatically increases the cost of support and development of the system as a whole.

The life cycle of stored procedures makes it difficult to use standard Change Management tools and practices. It is necessary to adapt the operations upon the stored procedures to the standards of Change Management, yet staying within the comfortable development practices.

We'll look at the typical tasks of the procedural extensions development and discuss the solutions we are implementing in the Xobot IDE.

Software applications working on PostgreSQL is a very typical case in my practice. Some of them manage to work well, some of them do not. In the talk I will focus on errors and problems of the last ones.

Gallery

The dark age for PostgreSQL started at 2GIS after transitioning to the microservice architecture. Every team tried to cook database on their own — by installing instances, juggling versions, trying to code deployments with numerous tools or using manual operations. It was the right time to develop a “silver bullet” — a common set of tools to solve all the problems at once. We created our own cluster solution based on well-known PostgreSQL, repmgr, pgbouncer and Barman. Despite of the complexity of our final solution, we developed a repeatable flexible deployment to accelerate postgresql cluster deployment and management. Also we deployed the our own cluster to consolidate all databases. It helped to eliminate team efforts for database management and focus on their main goals. Failover works, we tried it :-)