binaries and postgres

Can you just store binaries in postgres?

May 18, 2026 · 2 min read · tech, programming

Postgres is awesome, but can You get away with it being a filesystem or stash space for your application. here are some calculations I did.

there are a few types, depending on your application,

bytea (byte Array) - basically a dumb byte array. good for stash once and forget. updates are tricky because you’d have to read the whole thing and update, leading to write amplification. size limit of 1GB.
Binary Large Objects (BLOB) - can stream data to the same row. basically cheap append only binary. size limit of 1GB.
JSONB - can store JSON text in a custom binary format, allowing for quick key look up over the binary.

a note on TOAST

postgres default page size is 8KB. a single table tuple cannot span multiple pages in postgres.

when a field exceeds 2KB, Postgres offloads the data to TOAST (The Oversized-Attribute Storage Technique)

There is a separate TOAST table where postgres stores this data automatically.

backups become complex.
Failover and recovery takes too long.
DB dump take longer (because of the large database size).
Difficult to handle exponential scaling.
In managed services, cost grows massively. (because typically they’re charge per GB stored)

the operational complexity is a little too high in my opinion even though immediately consistent