In previous versions of MySQL, the dictionary data was partially stored in the metadata file type. Frequently encountered problems of storage related to these files, based on the type metadata, included scans of very expensive files. Thus, vulnerability to bugs related to the filesystem, complex code to handle failures for data replication and disaster recovery, and a lack of scalability made it difficult to add metadata to new features and relational objects.
Remember, in our previous section on the MySQL data dictionary structure in MySQL 8.0, we saw a graph of the data dictionary before MySQL 8.0, where the data dictionary was surrounded by auxiliary files. Now, with MySQL 8.0, the following list of files will be removed and replaced with tables:
- .frm
- .par
- .trn
- .trg
- .isl
- db.opt
It is better to have metadata managed from tables than files...