Migration errors
Fix: ERROR 1118 — Row size too large when creating tables
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type … is 65535.When it happens
Creating MySQL tables with many VARCHAR columns — often after converting a PostgreSQL schema with wide text columns.
Why it happens
MySQL limits a row (excluding TEXT/BLOB) to 65,535 bytes. With utf8mb4, VARCHAR(n) reserves up to 4n bytes, so a few VARCHAR(4096) columns already blow the limit.
How to fix it
1. Move wide columns to TEXT
ALTER TABLE t MODIFY long_field TEXT;TEXT/BLOB columns count only ~12 bytes toward the row limit.
2. Audit the widest columns
SELECT column_name, character_maximum_length
FROM information_schema.columns
WHERE table_name='t' ORDER BY 2 DESC;3. Converting from PostgreSQL with us?
Long varchars are widened to LONGTEXT automatically, so generated schemas stay under the row-size limit.
Migrating between MySQL and PostgreSQL?
Our converter handles this and dozens of other gotchas automatically — upload a dump, download working SQL.
Try the converter free