Data Block Manager

The Data Block Manager brings data blocks into memory, writes them out to data files, handles data compression, and writes data files to disk. The Data Block Manager controls four components. The following table describes each component:

Table 151 lists the components that Data Block Manager controls:

Table 151. Data Block Manager Components

Component

Description

Data file

A file that contains data blocks. Essbase generates the data file upon data load and stores it on disk. Essbase names data files incrementally—essxxxxx.pag, where xxxxx is a number, starting with 00001.

Data block

The primary storage unit within Essbase. A data block is a multidimensional array that represents cells of the dense dimensions for a given intersection of sparse dimensions.

Data cache

A buffer in memory that holds uncompressed data blocks.

Data file cache

A buffer in memory that holds compressed data files (.pag).

The size of the data file cache determines how much of the data within the data files can fit into memory simultaneously. The data cache size and the data block size determine how many data blocks can fit into memory simultaneously. Data files for a single database can span multiple volumes; multiple databases can reside on the same volume. See Sizing the Data File Cache and Sizing the Data Cache. Also see Specifying Disk Volumes.