PgConf.Russia 2019

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)

When you are optimizing Postgres it is usually maintenance that goes by the wayside. How do we fix autovacuum? Where did all of this bloat come from? Why am I getting IO spikes? How do I get RDS to behave?! Why are commits so slow on replication? The answer to all of these questions is understanding the relationship between proper Postgres maintenance and performance. Join us for a 3 hour jaunt through the wily world of making Postgres Go!

Declarative partitioning was a long-awaited feature and has been enhanced since its introduction in PostgreSQL 10. However, for many users, finding optimal partitioning schemes to have the best benefits from partitioning is not an easy task. Therefore, we added in HypoPG a new hypothetical partitioning feature which helps users to design partitioning. In this presentation, I will provide a brief introduction of HypoPG and explain declarative partitioning, and then I'll show the usage of hypothetical partitioning feature and explain how the extension is working.

Python may not be the fastest programming language on the CPU, but its fast and easy development saves a lot of costs between the keyboard and the chair. Since database clients spend most of their time waiting for a response from the database server, Python's asynchronous functionality available in the recent versions (3.5+) may help to optimize the application's runtime considerably by working on something else while server's response is being prepared. The asynchronous interface between Python and PostgreSQL is called "asyncpg". In the workshop we'll explore this library and write a short application using some of its useful features.