# X_MIGRATION_PARTITION_CHANGE

## Means

an existing table gained or lost entity({ partitionBy })

## Typical cause

Postgres cannot partition a table in place, nor turn a partitioned one back into a plain table: both are a new table and a copy of every row

## Fix

`put partitionBy back as the table was created, or declare a new entity with partitionBy, backfill() its rows from the old one, then drop the old one in a later release (wiki/Migrations-And-Backfills.md#partitioned-tables)`

[Entity and database](/error-codes#entity-and-database)