What is New in NDB Cluster or tablespace, the parent schema is  NULL .) In addition, the  ndb_sync_excluded_objects  table shows the reason for which the object has been excluded. These tables are present only if  NDBCLUSTER  storage engine support is enabled. For more information about these tables, see Section 27.12.12, “Performance Schema NDB Cluster Tables” . This metadata is accessible using the NDB API methods  getExtraMetadata()  and setExtraMetadata()  that were implemented in NDB 8.0.13. For more information, see Section 23.2.7, “Upgrading and Downgrading NDB Cluster” . Once a table’s structure has been modified in NDB 8.0, its metadata is stored using the data dictionary, and it can no longer be accessed by NDB 7.6 and earlier. This enhancement also makes it possible to restore an  NDB  backup made using an earlier version to a cluster running NDB 8.0 (or later). In addition, details of any mismatches in metadata properties are now written to the MySQL server error log. The formats used for the error log messages differ slightly depending on whether the discrepancy is found on the table level or on the level of a column, index, or foreign key. The format for a log error resulting from a table-level property mismatch is shown here, where  property • Changes in NDB table extra metadata.   In NDB 8.0.14 and later, the extra metadata property of an  NDB  table is used for storing serialized metadata from the MySQL data dictionary, rather than storing the binary representation of the table as in previous versions. (This was a  .frm  file, no longer used by the MySQL Server—see Chapter 14,  MySQL Data Dictionary .) As part of the work to support this change, the available size of the table’s extra metadata has been increased. This means that  NDB tables created in NDB Cluster 8.0.14 and later are not compatible with previous NDB Cluster releases. Tables created in previous releases can be used with NDB 8.0.14 and later, but cannot be opened afterwards by an earlier version. • On-the-fly upgrades of tables using .frm files.   A table created in NDB 7.6 and earlier contains metadata in the form of a compressed  .frm  file, which is no longer supported in MySQL 8.0. To facilitate online upgrades to NDB 8.0,  NDB  performs on-the-fly translation of this metadata and writes it into the MySQL Server’s data dictionary, which enables the  mysqld  in NDB Cluster 8.0 to work with the table without preventing subsequent use of the table by a previous version of the  NDB  software. Important • Metadata consistency check error logging.   As part of work previously done in NDB 8.0, the metadata check performed as part of auto-synchronization between the representation of an  NDB table in the NDB dictionary and its counterpart in the MySQL data dictionary includes the table’s name, storage engine, and internal ID. Beginning with NDB 8.0.23, the range of properties checked is expanded to include properties of the following data objects: •Columns •Indexes •Foreign keys 3937