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Databases & Data

The most popular blog posts about databases & data on Hacker News. 314 posts.

2021
271

Why query planning for streaming systems is hard

Many groups are working on running sql queries in incremental/streaming systems . Query planning in this context is not a well understood problem. This post is a quick pointer towards the many open problems. It's not intended to be complete or authoritative, because I haven't engaged with the problem much beyond…

277

PostgreSQL Subtransactions Considered Harmful

PostgreSQL subtransactions (nested transactions) may cause multiple performance and scalability issues: higher rates of XID growth and higher risks of transaction ID wraparound, performance degradation when more than PGPROC_MAX_CACHED_SUBXIDS (64) are used in a session, drastic performance slowdowns when…

281

SQL vs. NoSQL Is the Wrong Distinction

A misconception that I held for a really long time was that systems that use SQL (Structured Query Language) are by definition relational databases, and systems that don’t (e.g., MongoDB, Cassandra) are non-relational. It’s easy to understand whether a database uses SQL or not, but what does it mean when we say a…

297

The 74,000 numbers of Barclays Bank

The UK faces an epidemic of telephone scams. Fraudsters are constantly calling people up pretending to be their bank. But how can you be sure the number displayed on your screen in genuine? You can't. The telecom system is hopelessly insecure and shouldn't be trusted for anything more complicated than dialling the…