Troubleshooting InnoDB Data Dictionary Operations 15.21.3 Troubleshooting InnoDB Data Dictionary Operations Cannot Open Datafile Restoring Orphan File-Per-Table ibd Files If a high  innodb_force_recovery  value is required to start  InnoDB , there may be corrupted data structures that could cause complex queries (queries containing  WHERE ,  ORDER BY , or other clauses) to fail. In this case, you may only be able to run basic  SELECT * FROM t  queries. Information about table definitions is stored in the InnoDB data dictionary. If you move data files around, dictionary data can become inconsistent. If a data dictionary corruption or consistency issue prevents you from starting  InnoDB , see Section 15.21.2, “Forcing InnoDB Recovery”  for information about manual recovery. With  innodb_file_per_table  enabled (the default), the following messages may appear at startup if a file-per-table tablespace file ( .ibd  file) is missing: To address these messages, issue  DROP TABLE  statement to remove data about the missing table from the data dictionary. This procedure describes how to restore orphan file-per-table  .ibd  files to another MySQL instance. You might use this procedure if the system tablespace is lost or unrecoverable and you want to restore  .ibd file backups on a new MySQL instance. The procedure assumes that you only have  .ibd  file backups, you are recovering to the same version of MySQL that initially created the orphan  .ibd  files, and that  .ibd  file backups are clean. See Section 15.6.1.4, “Moving or Copying InnoDB Tables”  for information about creating clean backups. The procedure is not supported for general tablespace  .ibd  files. Table import limitations outlined in Section 15.6.1.3, “Importing InnoDB Tables”  are applicable to this procedure. 1. On the new MySQL instance, recreate the table in a database of the same name. 2. Discard the tablespace of the newly created table. 3. Copy the orphan  .ibd  file from your backup directory to the new database directory. 3393 mysql>  CREATE DATABASE sakila; mysql>  USE sakila; mysql>  CREATE TABLE actor ( actor_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, first_name VARCHAR(45) NOT NULL, last_name VARCHAR(45) NOT NULL, last_update TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (actor_id), KEY idx_actor_last_name (last_name) )ENGINE=InnoDB DEFAULT CHARSET=utf8; mysql>  ALTER TABLE sakila.actor DISCARD TABLESPACE; [ERROR] InnoDB: Operating system error number 2 in a file operation. [ERROR] InnoDB: The error means the system cannot find the path specified. [ERROR] InnoDB: Cannot open datafile for read-only: ’./test/t1.ibd’ OS error: 71 [Warning] InnoDB: Ignoring tablespace ‘test/t1‘ because it could not be opened.