Company
Date Published
Author
Ben Darnell
Word count
820
Language
English
Hacker News points
None

Summary

CockroachDB's integration with SQLAlchemy is currently in beta, with ongoing enhancements to improve compatibility. The integration allows developers to build applications using Python, SQLAlchemy, and Flask, with a few necessary adaptations due to CockroachDB's unique features. Key differences include the use of the `SHOW TABLES` command instead of `pg_tables`, the preference for `INT DEFAULT unique_rowid()` over `SERIAL` for automatic ID columns, and the lack of support for foreign keys. A notable aspect of CockroachDB is its use of optimistic concurrency control, which requires handling transaction retries efficiently using the `SAVEPOINT` statement. The tutorial illustrates how to modify a Flask-SQLAlchemy app to accommodate these features, emphasizing the importance of correctly managing restarted transactions with the `cockroachdb.sqlalchemy.run_transaction` function. The example provided demonstrates how CockroachDB's approach enables retry mechanisms by preserving information about transaction attempts, which differs from traditional databases' locking mechanisms.