At the current pace of media content creation, Reddit expects their media metadata to be roughly 50 terabytes. This means they need to implement sharding and partition their tables across multiple Postgres instances.

Reddit shards their tables based on post_id where they use range-based partitioning. All posts with a post_id in a certain range will ... See more

Data bases have gotten so good at this, that the term is almost misleading now. “Base” suggests something rigid, without which the data would slip away. But the data is always there, just bits on a nameless hard disk. The structure and the accessibility that a modern database provides exist completely independently from that hard disk. That’s right... See more