too_many_columns tables can have at most 1600 columns — 54011

Symptoms

A table definition exceeded PostgreSQL’s hard limit on the number of columns. PostgreSQL raises SQLSTATE 54011 (too_many_columns).

• A CREATE/ALTER TABLE pushed past the column cap.
• The effective limit is 1600 (often fewer for wide types).
• Common with extremely wide, denormalized tables.

What the server log shows

ERROR:  tables can have at most 1600 columns

Why PostgreSQL raises this — what the manual says

Appendix K PostgreSQL Limitations:

“Columns that have been dropped from the table also contribute to the maximum column limit.”

Each row must fit page/tuple constraints, capping columns at 1600 (fewer for wide types). A definition exceeding the cap can’t be stored, so PostgreSQL reports 54011.

Common causes

• An over-denormalized table with too many columns.
• Repeatedly adding columns to a very wide table.
• Generated/EAV-style schemas creating excessive columns.

How to fix it

1. Normalize: split the table into related tables.
2. Use JSONB or arrays for sparse/variable attributes instead of many columns.
3. Reconsider the schema design to stay well under the limit.

Related & next steps

• SQLSTATE 54011 — Too Many Columns (full reference)
• Message: index row size exceeds maximum
• Glossary: Normalization

Reference: PostgreSQL 18 Appendix K “Limits”.