PgConf.Russia 2019

Stop paying for Larry’s boat!

PostgreSQL is a fully-featured, enterprise-grade and open source database, named two years in a row database of the year! And it’s also the best candidate to migrate off of Oracle, supporting very advanced SQL, easy administration and pl/pgsql, a replacement for Oracle’s PL/SQL. Stop spending hundreds of thousands or millions of $ on database licenses and reinvest them in your team, infrastructure and software.

Join this half-day tutorial to learn the best practices, tricks and tools to perform a successful Oracle to PostgreSQL migration. Learn from the team that performed 150M users Blackberry migration to PostgreSQL on GCP with near-zero downtime, and the key author behind orafce, a set of Oracle compatible functions on top of PostgreSQL.

PostgreSQL + PostGIS + TimescaleDB is a ready-to-use symbiosis from a reliable RDBMS, a powerful set of geographical objects and calculations, and work with time-series data. This bundle perfectly solves the problem of storing telemetry, while leaving the whole PostgreSQL ecosystem in your hands.

In my talk I'll tell you about practices of working with Postgres in the Go-services. I’ll describe general advantages and disadvantages of the basic tools that are commonly used when working with Postgres using Go. Of course, we will touch on the nuances that need to be taken into account when your services are running inside the Kubernetes. I will also talk about Avito’s experience in providing a database of product’s developers. This presentation will be of interest to developers who want to avoid problems when working with Postgres, and will be useful to DBA who want to know what difficulties customers face in their database.

As is often seen in OLAP and batch processing workloads, the more complex a query (containing many joins, filters, aggregates), the more there is a possibility of row count estimation errors, which leads to planner choosing an inefficient execution plan.

To address that problem, I developed a tool called pg_plan_advsr as a PostgreSQL extension, which corrects the estimation errors by repeatedly feeding back the information collected during query execution to the planner.

The tool has three features:

1. Automatic plan tuning by repeatedly feeding execution information to planner
2. Preserve all plans generated during plan tuning in a history table
3. Create and store optimizer hints to be able to reproduce plans generated during tuning process

I verified the effectiveness of pg_plan_advsr by enabling it when running the join order benchmark (JOB) against PG 10.4 and observed its execution time shortening to 50% of the original. Therefore, it is useful for user who would like to do plan tuning for OLAP and batch processing.

I will talk about the following things in this presentation:

• Principles behind pg_plan_advsr and its architecture
• Detailed information about the measurements done with JOB
• Possible future enhancements
• Using aqo and pg_plan_advsr together (experimental)