Nikolay and Michael discuss PostgreSQL subtransactions — what they are, and four issues they can cause at scale. 
 
Here are some links to things they mentioned:

• Subtransactions (docs) https://www.postgresql.org/docs/current/subxacts.html  
• SAVEPOINT (docs) https://www.postgresql.org/docs/current/sql-savepoint.html  
• PostgreSQL Subtransactions Considered Harmful (blog post by Nikolay) https://postgres.ai/blog/20210831-postgresql-subtransactions-considered-harmful  
• Subtransactions and performance in PostgreSQL (blog post by Laurenz at Cybertec) https://www.cybertec-postgresql.com/en/subtransactions-and-performance-in-postgresql/  
• Notes on some PostgreSQL implementation details (blog post by Nelson Elhage) https://buttondown.email/nelhage/archive/notes-on-some-postgresql-implementation-details/ 
• Why we spent the last month eliminating PostgreSQL subtransactions (GitLab blog post) https://about.gitlab.com/blog/2021/09/29/why-we-spent-the-last-month-eliminating-postgresql-subtransactions/  

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What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!

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Postgres FM is brought to you by:

• Nikolay Samokhvalov, founder of Postgres.ai
• Michael Christofides, founder of pgMustard

With special thanks to:

• Jessie Draws for the amazing artwork