Storage hierarchy in Oracle databases

The Storage Level System database in the Oracle database consists of one or more tablespaces. A table space is a logical storage container in Oracle. It is located at the top of the storage hierarchy and contains one or more data files. First, understand what is a table space, what is a segment, what is a partition, and what is a block ), these are the allocation units used to store objects in Oracle databases. Segment 1 of www.2cto.com, which is the main organizational structure in the tablespace. Segments are the database objects that occupy storage space, such as tables, indexes, and rollback segments. Section 2 consists of one or more sections. A partition is a logical continuous allocated space in a file. (In general, the file itself is not continuous on the disk ). Traditionally, each segment has at least one segment, and some objects may need multiple segments (two segments are required for rollback ), these segments may not be allocated in the same file, but the space in the segments is always a logical continuous space of a file. The three segments are further composed of blocks. A block is the smallest space allocation unit in Oracle. For data rows, index entries or temporary sorting results are stored in blocks. Common Oracle block sizes include 2 kb, 4 kb, 8 KB, or 16 kb. www.2cto.com a CIDR block consists of one or more CIDR blocks, which are consecutively allocated. In all given tablespaces, the block size is the same, which means that all the blocks in a tablespace are the same size. 4. A tablespace is a container, including segments. Each segment belongs to only one tablespace. A tablespace may have multiple segments. All regions of a given segment are in the tablespace associated with the segment. It will never span the tablespace boundary. The tablespace itself can have one or more related files. A region of a given segment in a tablespace is completely contained in a data file. However, the segment can come from different data files. The storage hierarchy summary database consists of one or more tablespaces. A tablespace consists of one or more data files. A cidr block consists of one or more CIDR blocks. Segments are in the tablespace, but can contain data in multiple data files in the tablespace. The www.2cto.com block is a logical continuous block on the disk. The partition is only in one tablespace and is always in one file in the tablespace. A block is the smallest allocation unit in the database and the smallest I/O unit used by the database.