In the InnoDB storage engine, the tables are stored in order according to the primary key. This storage method is called the index organization table.
InnoDB logical storage structure
InnoDB from the logical structure storage perspective, from large to small dimensions are: table space, segment (segment), area (extent), page (page).
Table space
InnoDB's top-level logical structure, all data is stored in the table space.
Innodb_file_per_table parameter, you can set the data in each table to be stored in a separate table space. However, only data, indexes, and inserted buffer bitmap pages are stored. Other types of data, rollback information, insert buffer index pages, system transaction information, secondary write buffer, etc. are still stored in the shared table space.
segment
Common segments include data segments, index segments, and rollback segments. The data segment is the leaf node of the B + tree, and the index segment is the non-index node of the B + tree,
Area
The area is a space composed of consecutive pages. In order to ensure the continuity of the pages in the area, the InnoDB storage engine applies for 4 to 5 areas from the disk at a time.
page
The smallest unit of InnoDB disk management, the default size of each page is 16KB.
Common page types in the InnoDB storage engine are:
- Data Page (B-tree Node)
- undo page (undo Log Page)
- System Page
- Transaction data page (Transaction system Page)
- Insert Buffer Bitmap page (Insert Buffer Bitmap)
- Insert Buffer Free List page (Insert Buffer Free List)
- Uncompressed binary large object page (Uncompressed BLOB Page)
- Compressed binary large object page (compressed BLOB page)
Row
InnoDB is column-oriented, which means that the data is stored in rows.