# Page Not Found

The URL `ref/mdb/error-codes/ER_COMPRESSED_COLUMN_USED_AS_KEY` does not exist.

You might be looking for one of these pages:
- [MariaDB Error Code Reference](https://mariadb.com/docs/server/reference/error-codes/mariadb-error-code-reference.md)
- [COM_RESET_CONNECTION](https://mariadb.com/docs/server/reference/clientserver-protocol/2-text-protocol/com_reset_connection.md)
- [Information Schema KEY_COLUMN_USAGE Table](https://mariadb.com/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-key_column_usage-table.md)
- [Performance Schema Status Variables](https://mariadb.com/docs/server/reference/system-tables/performance-schema/performance-schema-status-variables.md)
- [mysql.column_stats Table](https://mariadb.com/docs/server/reference/system-tables/the-mysql-database-tables/mysql-column_stats-table.md)

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2. **View the full content**: [/llms-full.txt](https://mariadb.com/docs/llms-full.txt) - Full content export

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