PgConf.Russia 2020

A brief story how MySQL → PG migration could increase company efficiency tenfold times:

1. Program code has been reduced 50 times, with optimization of backend team (from 15 to 3 engineers)
2. Software development of new features has become measuring in days, not in months
3. Infrastructure costs per 1M users have been reduced 20 times
4. Database structure and technical documentation were simplified significantly, from 100K high-dependent tables to just 20 simple tables
5. New security level because of total forbidden on external SQL commands to the database
6. Quick analytics aggregation on multiple parameters, without external analytics systems
7. The last, but not the least: the main business was keeping alive during migration

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.

We would like to share our test results (including performance testing) of PostgreSQL/Citrus and MongoDB for our company's data. It has been a very exciting process with unexpected turns and a somewhat controversial outcome.

Odyssey is a new PostgreSQL connection pooler designed for the high-load environment. It can significantly scale processing performance by specifying the number of additional worker threads. This allows to increase SSL/TLS performance and provide more balanced pooling control using by sharing global server connection pools. In this talk I will answer 4 questions: 1. When you should use connection pooler? When Odyssey is the most optimal choice? 2. How to set up a cluster with Odyssey? 3. How to sleep well and be sure that everything works? 4. How does the architecture of Odyssey look like? How to implement or propose feature that you want?