Data storage

The database server uses physical units of storage to allocate disk space. It stores data in logical units. Unlike the logical units of storage whose size fluctuates, each of the physical units has a fixed or assigned size that is determined by the disk architecture.

The following topics define terms and explain concepts that you must understand to manage disk space. These topics cover the following areas:

The database server uses the following physical units to manage disk space:
Chunks
Pages
Blobpages
Sbpages
Extents
The database server stores data in the following logical units:
Dbspaces
Temporary dbspaces
Blobspaces
Sbspaces
Temporary sbspaces
Plogspace
Extspaces
Databases
Tables
Tblspaces
Partitions and offsets
The database server maintains the following storage structures to ensure physical and logical consistency of data:
Logical log
Physical log
Reserved pages

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