Database file partitioning provides:
Easier management of large amounts of historical data, particularly for bulk data operations such as backups and deletions
Cost savings through the use of tiered disk storage, which enables you to split database files into partitions, with different partitions then being able to be stored on different media devices, tiered disk storage, or both different media devices and tiered disk storage
The ability to move objects between partitions programmatically, which enables you to avoid accessing historical information if it is not required, thereby improving performance of online and batch operations
A logical database file can be split into several parts, or partitions, where each partition corresponds to a physical file at the file system level. A logical database file is identified by its schema-defined name and is addressable by its name or number. A file partition is addressable by a
When the
A prerequisite for partitioning a database file is that a single class is mapped to the file.
Partitioning a class enables you to locate instances in different partitions of a database file. A file partition is therefore a part of a database file containing a subset of instances of a single class.
When a database file has been partitioned, the set of partitions associated with a schema-defined map file is referred to as a partition set.
The external file name assigned to a file partition is derived from the schema-defined file name and incorporating the partition number as a qualifier, with the following format.
<map_file_name>_part<partition-number>.dat
For details about replicating partitioned file structures and most meta data on SDS secondary databases, see "
The
The partition is converted to a read-only state, allowing its relocation to read-only media
Objects read from the partition are marked as frozen, overriding individual object volatility state
When a partition is thawed:
The read-only status is removed, allowing updates to objects residing in the partition
Volatility reverts to transparent, removing the frozen override