# When JSONB columns create schema, consistency, and performance problems

DevFeed: [When JSONB columns create schema, consistency, and performance problems](<https://devfeed.tech/articles/your-jsonb-column-became-the-schemaless-disaster-you-migrated-away-from-39598.md>)

Original publisher: [Read original article](<https://ankit-rana.com/logs/46-jsonb-column-schemaless-disaster/>)

Author: hello@ankit-rana.com

Published: 2026-09-01T00:00:00Z

Content type: article

Language: en

Sources: [Ankit Rana | Mechanical Sympathy](<https://devfeed.tech/sources/ankit-rana-mechanical-sympathy.md>)

Topics: [data](<https://devfeed.tech/topics/data.md>), [Structured-data](<https://devfeed.tech/topics/structured-data.md>), [JSON](<https://devfeed.tech/topics/json.md>)

Tags: [data-modelling](<https://devfeed.tech/tags/data-modelling.md>), [indexing](<https://devfeed.tech/tags/indexing.md>), [jsonb](<https://devfeed.tech/tags/jsonb.md>), [migration](<https://devfeed.tech/tags/migration.md>), [outage](<https://devfeed.tech/tags/outage.md>), [postgres](<https://devfeed.tech/tags/postgres.md>), [postgresql](<https://devfeed.tech/tags/postgresql.md>), [query](<https://devfeed.tech/tags/query.md>), [schema](<https://devfeed.tech/tags/schema.md>), [schema-design](<https://devfeed.tech/tags/schema-design.md>), [toast](<https://devfeed.tech/tags/toast.md>)

## AI overview

The article explains why using JSONB to avoid recurring migrations can create hidden schema and data-consistency problems. It discusses runtime failures from inconsistent keys and types, difficulty identifying dependencies across consumers, and the storage and update costs of large PostgreSQL JSONB documents.

## Source excerpt

JSONB is a good fit for genuinely open-ended data and a poor one for schema you did not want to commit to yet. Without a schema there is no NOT NULL, no type, no foreign key and no way to know which keys are load bearing, so every read becomes a parse and a cast that can fail at runtime. Large documents are stored out of line and compressed, which means reading one key can require fetching and decompressing the whole document, and updating one key rewrites all of it.