PGConf.Russia 2022

As opposed to in-memory DBMSs, traditional disc database management systems have an inherent physical limitation. It's their storage system which is by several orders of magnitude slower than CPU operation memory, even in the case of All-Flash NVM. It becomes especially critical for the development of business analytics apps and OLAP scenarios on disc DBMS. We will consider a number how-tos for improving the performance of traditional DBMSs, and then offer a new storage-centric approach to hardware-based speed-up for disc DBMSs.

In June 2020, AlfaStrakhovaniye was obliged to use RSA 2.0 government services along with other insurance companies. It was the only way to sell car insurance in Russia. AlfaStrakhovaniye is a leader in car insurance, and its applications degraded under the pressure of calls. It wasn't planned. Postgres used a huge amount of CPU and memory. Nobody could tell what was going on. Degradation started and stopped for no reason. Dev Team and Postgres Pro experts solved that problem. MyBatis in Java services was the killer. Our story is about the development of applications for heavy workloads and technical ignorance while using frameworks.

PostgreSQL has a number of peculiarities that you need to take into account not only while maintaining your database but also when designing your database schema. Experienced PostgreSQL are well aware of vacuuming process. On the web one can find tons of materials covering its internals, configurations and monitoring. Many valuable talks about vacuum were given at numerous conferences. However, we still face the common wraparound problem when the maximum possible number of transactions (xid) is reached. It happens even on databases that are relatively small in size. In my presentation, I will share a customer case that looks interesting to me. A chain of mistakes made at different stages of the database's life cycle once caused a disaster. The database fully stopped for one week, we detected a wraparound and spotted corrupted blocks. Maintenance was problematical, and we spent sleepless nights in search of a solution. We managed to achieve a local win as we finally restored the database, but it's not the end of this story, which makes it even more interesting.

The talk covers the use of PostgreSQL, LUI and LUI4ORA2PG for building an analytical reporting system.

The talk tackles the following topics:

• migration from an Oracle environment;
• application of JSON functions;
• how the temporary tables helped us;
• our own means for load testing and bottlenecks detection;
• how to make beautiful GeoJSON format maps to display diagrams on them;
• installation and testing of the system on an "Elbrus" computer;
• what became an obstacle or was missing when using PostgreSQL.

The history of growth of the Live Universal Interface (LUI) web application development tool and the LUI4ORA2PG migration tool can be found in our previous presentations at PGConf conferences:

https://pgconf.ru/2019/118109 ;

https://pgconf.ru/201911/264095 ;

https://pgconf.ru/2020/262456 ;

https://pgconf.ru/2021/288310 .